TWI247815B - Low-carbon free cutting steel - Google Patents
Low-carbon free cutting steel Download PDFInfo
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- TWI247815B TWI247815B TW093119223A TW93119223A TWI247815B TW I247815 B TWI247815 B TW I247815B TW 093119223 A TW093119223 A TW 093119223A TW 93119223 A TW93119223 A TW 93119223A TW I247815 B TWI247815 B TW I247815B
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 42
- 229910000915 Free machining steel Inorganic materials 0.000 title abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 191
- 239000010959 steel Substances 0.000 claims abstract description 191
- 238000005096 rolling process Methods 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 14
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 14
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 239000001301 oxygen Substances 0.000 claims description 13
- 229910052718 tin Inorganic materials 0.000 claims description 11
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 9
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- -1 substituted Chemical class 0.000 claims description 4
- 229910052714 tellurium Inorganic materials 0.000 claims description 4
- 229910052797 bismuth Inorganic materials 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims 1
- 239000002131 composite material Substances 0.000 abstract description 12
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 2
- 238000005520 cutting process Methods 0.000 description 52
- 230000000694 effects Effects 0.000 description 51
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 41
- DXHPZXWIPWDXHJ-UHFFFAOYSA-N carbon monosulfide Chemical compound [S+]#[C-] DXHPZXWIPWDXHJ-UHFFFAOYSA-N 0.000 description 31
- 239000000463 material Substances 0.000 description 31
- 238000012360 testing method Methods 0.000 description 22
- 150000004767 nitrides Chemical class 0.000 description 19
- 150000001247 metal acetylides Chemical class 0.000 description 17
- 239000000203 mixture Substances 0.000 description 16
- 150000004763 sulfides Chemical class 0.000 description 16
- 238000005255 carburizing Methods 0.000 description 14
- 238000012545 processing Methods 0.000 description 14
- 230000015572 biosynthetic process Effects 0.000 description 12
- 239000000126 substance Substances 0.000 description 11
- 230000006872 improvement Effects 0.000 description 10
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 230000001050 lubricating effect Effects 0.000 description 8
- 229920006395 saturated elastomer Polymers 0.000 description 8
- 230000006866 deterioration Effects 0.000 description 7
- 239000010955 niobium Substances 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 229910052804 chromium Inorganic materials 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 6
- 230000003746 surface roughness Effects 0.000 description 6
- 238000009749 continuous casting Methods 0.000 description 5
- 238000005461 lubrication Methods 0.000 description 5
- 239000011159 matrix material Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 238000003754 machining Methods 0.000 description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 229910052726 zirconium Inorganic materials 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000003763 carbonization Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- QGJOPFRUJISHPQ-UHFFFAOYSA-N Carbon disulfide Chemical compound S=C=S QGJOPFRUJISHPQ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000012790 confirmation Methods 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000010191 image analysis Methods 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 229910052711 selenium Inorganic materials 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 229910001152 Bi alloy Inorganic materials 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 241001422033 Thestylus Species 0.000 description 1
- 229910052768 actinide Inorganic materials 0.000 description 1
- 150000001255 actinides Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000003703 image analysis method Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 230000019086 sulfide ion homeostasis Effects 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000005211 surface analysis Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
1247815 ⑴ 玖、發明說明 【發明所屬之技術領域】 本發明係有關於不含鉛（Pb )之低碳易割鋼。特別係 有關於，不僅不含鉛，較之習知鉛易割鋼及與鉛倂用其它 易割性改善元素之複合易割鋼，在用超硬工具切割時亦具 優異被割性，熱加工性及切割後之加工面性狀亦優，且能 廉價製造之低碳易割鋼。本發明並係有關於，連同上述諸 特性，滲碳特性亦優之低碳易割鋼。 【先前技術】 向來，於強度要求不甚高之軟質小零件，爲提升生產 力，係使用被割性優良之鋼材，所謂易割鋼。最爲所知的 易割鋼係大量添加S，以MnS改善被割性之硫易割鋼，及 含S及Pb二者之複合易割鋼。尤以含Pb之易割鋼具有， 可保工具壽命之延長，切屑離斷性優，加工後鋼材表面之 加工面粗細優之特性。更爲改善被割性，有含Te (碲） 、Bi (鉍）等之易割鋼。此等已大量使用於，汽車用之煞 車零件等小零件、個人電腦週邊機器零件，以至於電機零 件、模具等各種機械零件。 另一方面，近年來切割機械之性能提升，高速切割成 爲可能，隨之如上零件之材料鋼材，其於高速切割加工時 之被割性的提升受到強烈期待。 又再，上述零件經切割加工完成特定形狀後，爲確保 表面強度，有時施以滲碳處理。因此，用於此等零件之鋼 -5- (2) 1247815 材連同高被割性，有滲碳特性亦優之期待。 用作如上零件材料之鋼材有優良被割性之要求，該被 割性不僅於工具壽命之延長，於切屑之微細離斷之性質， 即「切屑處理性」優良亦屬重要。該切屑處理性係加工線 自動化所不可或缺，於生產力之提升亦屬必要。又，工具 壽命、切屑處理性以外，從加工精度之觀點，亦期待切割 後鋼材表面之加工面性狀優，亦即加工面之粗度低。上述 易割鋼之中，鉛易割鋼、連同Pb含有其它易割性改善元 素之複合易割鋼的此等諸特性優，乃現存鋼材之中被割性 最優者。 近年來，在對環境問題之關懷升高當中，對於不含 Pb之易割鋼有強烈需求。此不僅係含對人體、地球環境 有害之鉛的鋼材於製程須有大型排氣設備，從環保觀點， 抑制Pb之使用的功能亦日漸升高。 爲回應上述企盼，關於取代鉛易割鋼之不含Pb的低 碳硫易割鋼已有種種提議。但有助於工具壽命之延長，切 屑處理性優，加工面粗度小等含Pb易割鋼諸特徵能完全 滿足之易割鋼尙未見開發。 專利文獻1 (日本專利特開20 03 — 4924 0號公報）揭 示，使用Ti或/及Zr之碳硫化物系夾雜物存在，改善被 割性之易割鋼。該易割鋼因連同Mn S有Ti碳硫化物或Z 碳硫化物分散於鋼中，很難得到類似Mn S之潤滑效果， 工具與被割材料間之摩擦力上升。結果，切割阻力上升， 易於工具刀刃生成刀瘤。一產生刀瘤，則加工切割後之加 -6 - (3) 1247815 工面粗度大，有損於零件之加工精度。 0 . 1 %以下者。 i促使Ti碳硫 有Ti碳硫化物 3滿足工具壽命 二之鋼材的要求 J )揭示，於（ T i或 Z r之碳 ;孔加工時能提 丨係使鋼中生成 改善.。該技術 .碳硫化物的存 料間之摩擦力 生成刀瘤。一 加工精度劣化 發明所規定的 實施例。由此 細、切屑處理 明因連同 Μ n S 所欲之加工面 專利文獻1中，實施例未見有Ti含量 此表明專利文獻1之發明，係以大量含有^ 化物生成爲目的，並記載實際上連同Mn S 系夾雜物以粒狀分散於基質內。如此，無沒 、切屑處理性、加工面粗細等用於上述零伯 性能。 專利文獻2 (特開2003 — 4 924 1號公對1247815 (1) Description of the Invention [Technical Field of the Invention] The present invention relates to a low carbon easy-cut steel containing no lead (Pb). In particular, it is not only lead-free, but also has a good cut-off property when cutting with super-hard tools, compared with conventional lead-cut steel and other easy-cutting elements with lead-cutting improvement elements. Low-carbon easy-cut steel that is excellent in workability and after-cutting, and can be manufactured at low cost. The present invention is also related to a low carbon easily cut steel which is excellent in carburizing characteristics together with the above characteristics. [Prior Art] In the past, soft small parts with low strength requirements have been used to improve productivity, and steels with excellent cutability are used. The most well-known easy-cut steels are S with a large amount of S, improved sulphur-cut steel with MnS, and composite easy-cut steel with both S and Pb. In particular, the easy-cut steel with Pb has the property of prolonging the life of the tool, excellent chip breaking property, and excellent thickness of the machined surface on the surface after processing. It is more effective in improving the cutability, and there are easy-cut steels containing Te (碲) and Bi (铋). These have been widely used in small parts such as automobile parts for automobiles, machine parts around personal computers, and various mechanical parts such as motor parts and molds. On the other hand, in recent years, the performance of the cutting machine has been improved, and high-speed cutting has become possible. With the material steel of the above-mentioned parts, the improvement in the cutting property at the time of high-speed cutting processing is strongly expected. Further, after the above-mentioned parts are cut to a specific shape, in order to secure the surface strength, carburization treatment may be applied. Therefore, the steel used in these parts -5- (2) 1247815 is also expected to have high carburization properties. The steel used as the above-mentioned part material has a requirement of excellent cuttability, and this cuttability is important not only in the extension of the life of the tool but also in the finely-discharged nature of the chip, that is, the "chip handling property". This chip handling system is indispensable for the automation of processing lines, and it is necessary to improve productivity. Further, in addition to tool life and chip handling properties, from the viewpoint of processing accuracy, it is also expected that the surface property of the steel surface after cutting is excellent, that is, the thickness of the machined surface is low. Among the above-mentioned easy-cut steels, the lead-cut steel and the composite easy-cut steel in which Pb contains other susceptibility improving elements are excellent in the cut-off property among the existing steels. In recent years, there has been a strong demand for easy-cut steel without Pb in the rise of environmental concerns. This is not only a steel containing a lead that is harmful to the human body or the global environment, but also requires a large-scale exhaust equipment. From the viewpoint of environmental protection, the function of suppressing the use of Pb is also increasing. In response to these expectations, there have been proposals for replacing Pb-free low-carbon sulfur easy-cut steels that replace lead-cut steel. However, it has contributed to the development of the tool life, the excellent chip handling, the small thickness of the machined surface, and other features of the Pb-free cut steel that can be fully satisfied. Patent Document 1 (Japanese Laid-Open Patent Publication No. 20 03-4924 0) discloses the use of carbon or sulfide-based inclusions of Ti or/and Zr to improve the cutability of the easy-cut steel. The easy-cut steel is dispersed in steel together with Ti carbon sulfide or Z carbon sulfide in combination with Mn S, and it is difficult to obtain a lubricating effect similar to Mn S, and the friction between the tool and the material to be cut rises. As a result, the cutting resistance increases, making it easy for the tool blade to generate a knife blade. When a knife is produced, the machining after cutting is -6 - (3) 1247815 The thickness of the working face is large, which is detrimental to the machining accuracy of the part. 0. 1% or less. I promote the requirement that Ti carbon sulfur has Ti carbon sulfide 3 to meet the tool life of steel II. J) Reveal the carbon in (T i or Z r; the hole can be processed to improve the formation of steel.) The friction between the deposits of the carbon sulfide forms a knife. The processing accuracy deteriorates the embodiment specified by the invention. Therefore, the fineness and chip treatment are combined with the processing of the surface of the patent document 1 in which the Μ n S is desired. In the case of the Ti content, the invention of Patent Document 1 is intended to produce a large amount of a compound, and it is described that the Mn S-based inclusion is actually dispersed in the matrix in a granular form. Thus, no chipping, chip processing, processing The surface thickness and the like are used for the above-mentioned zero-shell performance. Patent Document 2 (Special Open 2003 - 4 924 1
Ti + 0.52Zr) /S<2之範圍含Ti或/及Zr，含 硫化物夾雜物之易割鋼，係於車削加工及點 高工具壽命之易割鋼。該專利文獻2之發明Ti + 0.52Zr) / S < 2 range containing Ti or / and Zr, easy-cut steel containing sulfide inclusions, is easy to cut steel for turning and high tool life. Invention of Patent Document 2
Ti碳硫化物，以謀車削加工時工具壽命之 確可某程度改善工具壽命，但因Ti或Zr之 在，難得MnS之潤滑效果，工具與被割材 上升。結果，切割阻力上升，工具刀刃容易 產生刀瘤，則切割後加工面之粗度大，結果 〇 專利文獻2中不見有，含如後敘之本 〇.21%以上之3，以量〇.1%以下的易割鋼之 可知，專利文獻2之發明並非針對加工面粗 性之提升的發明。亦即，專利文獻2之發 於基質內分散有Ti或Zr之碳硫化物，不得 粗度及切屑處理性。 專利文獻3 (特開2 0 0 0 — 3 1 9 7 5 3號公報）揭示含超 (4) 1247815 過0.4%之S以增加MnS，不添加Pb之低碳硫易割鋼。但 是，該鋼於超硬工具壽命之改善效果小。又，該鋼亦不在 於改善與工具壽命同屬重要之切屑處理性，並且於習知硫 快割鋼之性能未有多大改善。 專利文獻4(特開平〇9 - 53147號公報）揭示，含C :Ο · Ο 1 至 0.2 °/〇，S i ·· 0 · 1 〇 至 〇 · 6 0 %，Μ η ·· 0.5 至 1 · 7 5 %， Ρ: 0.005 至 0.15°/。，S: 0.15 至 0·40%，〇(氧）：0.001 至 0.010%，Ti : 0.0005 至 0.020%，Ν : 0.003 至 0.03%， 對於超硬工具之被割性，尤其是工具壽命優之易割鋼的發 明。該發明係連同T i必須含〇 . 1至〇 . 6 %之S i以謀超硬工 具的壽命之改善。又，該發明並非如本發明之不含Si而 亦使「內有Ti碳化物或/及Ti碳氮化物之實質上的MnS 」存在於鋼材中，不僅工具壽命，對謀取切屑處理性、加 工面粗細之提升。 專利文獻5 (專利第3 3 9 0 9 8 8號公報）揭示，含有C :0.02 至 0.15%’ Μη: 0.3 至 1.8°/。，S: 0.225 至 0.5%， Ti : 〇· 1 至 0.6%，Zr : 0· 1 至 0.6%，且滿足 Ti + Zr : 0.3 至 0.6%， （ Ti + Zr ) /S比：1」至1.5，機械各向異性獲改善 之低碳硫易割鋼之發明。該發明係利用上述組成，產生熱 變形抵抗力高之Ti、Zr硫化物，改善鋼材之機械各向異 性、被割性。但是由於變形抵抗力高之硫化物在切割時難 得硫化物之潤滑效果，切割阻力大，引起工具壽命之劣化 、加工面粗細之劣化。 專利文獻〗 特開2 0 0 3 — 4 9 2 4 0號公報 (5) 1247815 專利文獻2 特開2003— 49241號公報 專利文獻3 特開2 0 0 0 — 3 1 9 7 5 3號公報 專利文獻4 特開平0 9 - 5 3 1 4 7號公報 專利文獻5 專利第3 3 9 0 9 8 8號公報 【發明內容】 發明所欲解決之課題 本發明之課題在提供，不含有害環境之Pb，相較於 習知Pb易割鋼、連同Pb倂用其它易割性賦予元素之複合 易割鋼，特別是使用超硬工具切割時呈優秀被割性，熱加 工性優，且切割後表面性狀亦優，可廉價製造之低碳易割 鋼。又，上述諸特性以外亦具優秀之滲碳性的低碳易割鋼 之供給亦係本發明之課題。 用以解決課題之手段 硫化物等夾雜物之狀態於鋼之被割性大有影響已屬熟 知。含C、Ti、S、N、Ο之鋼所觀察到的夾雜物有多種。 有例如，Ti硫化物、Ti碳硫化物、Ti碳化物、Ti碳氮化 物、Ti氮化物、Ti氧化物。若更含Μη則亦有”MnS”之化 學式所表的Μη硫化物之存在。此等以外，含Al、Si則 亦有該等之氧化物存在。該等之存在形態有各種各樣，此 等夾雜物之組成、存在形態於鋼之被割性、其它機械特性 等大有影響。 本發明人等已於先前之專利申請2 002 - 2 63 6 8號就有 (6) 1247815 關不含Pb之低碳硫易割鋼的發明提出專利申請。該易割 鋼係其特徵爲：含C、Mn、S、Ti、Si、P、A1、0及N、 Ti及S之含量滿足下述之（A)式，Μη及S之原子比滿 足下述之（B )式，且含內有Ti硫化物或/及Ti碳硫化物 之MnS的低碳硫易割鋼。Ti-carbon sulfides can improve tool life to some extent in order to improve the tool life during turning. However, due to Ti or Zr, it is difficult to obtain the lubrication effect of MnS, and the tool and the material to be cut rise. As a result, the cutting resistance increases, and the blade edge of the tool blade is likely to be generated, and the thickness of the machined surface after cutting is large. As a result, it is not seen in Patent Document 2, and contains 2% of the above-mentioned 〇. 21% or more. As for the easy-cut steel of 1% or less, the invention of Patent Document 2 is not directed to the invention of the improvement of the roughness of the machined surface. That is, Patent Document 2 is a carbon sulfide in which Ti or Zr is dispersed in a matrix, and is not to be coarse or chip-treating. Patent Document 3 (Japanese Laid-Open Patent Publication No. Hei. No. Hei 2 0 0 0 - 3 1 9 7 3) discloses a low carbon sulfur easy-cut steel containing super (4) 1247815 over 0.4% S to increase MnS and no Pb. However, the steel has a small improvement in the life of the superhard tool. Moreover, the steel is not in the process of improving the chip handling properties that are important to the life of the tool, and the performance of the conventional sulfur-cut steel has not improved much. Patent Document 4 (Japanese Laid-Open Patent Publication No. Hei 9-53147) discloses that C: Ο · Ο 1 to 0.2 ° / 〇, S i · · 0 · 1 〇 to 〇 · 60 %, η η ·· 0.5 to 1 · 7 5 %, Ρ: 0.005 to 0.15°/. , S: 0.15 to 0.40%, 〇 (oxygen): 0.001 to 0.010%, Ti: 0.0005 to 0.020%, Ν: 0.003 to 0.03%, for the cuttability of super-hard tools, especially the tool life is easy The invention of cutting steel. The invention, together with T i , must contain 〇 1 to 〇 6 % of the S i in order to improve the life of the superhard tool. Further, this invention does not contain Si in the present invention, and "the substantially MnS containing Ti carbide or/and Ti carbonitride" is present in the steel material, and not only the tool life, but also the chip treatment property and processing. The increase in the thickness of the face. Patent Document 5 (Patent No. 3 3 9 0 8 8) discloses that C: 0.02 to 0.15%' Μη: 0.3 to 1.8 °/ is contained. , S: 0.225 to 0.5%, Ti: 〇·1 to 0.6%, Zr: 0·1 to 0.6%, and satisfy Ti + Zr : 0.3 to 0.6%, ( Ti + Zr ) / S ratio: 1" to 1.5 The invention of low carbon sulfur easy-cut steel with improved mechanical anisotropy. According to the invention, the Ti and Zr sulfides having high heat deformation resistance are generated by the above composition, and the mechanical anisotropy and the cut property of the steel material are improved. However, since the sulfide having high deformation resistance is difficult to obtain the lubricating effect of the sulfide at the time of cutting, the cutting resistance is large, causing deterioration of the life of the tool and deterioration of the thickness of the machined surface. CITATION LIST Patent Publication No. 2 0 0 3 - 4 9 2 4 0 (5) 1247815 Patent Document 2 JP-A-2003-49241 Patent Document 3 Special Open 2 0 0 0 — 3 1 9 7 5 [Problem to be solved by the present invention] The object of the present invention is to provide a harmful environment. Pb, compared with the conventional Pb easy-cut steel, together with Pb, other easy-cutting steel with other easy-cutting elements, especially when cut with super-hard tools, excellent cuttability, excellent hot workability, and after cutting Low-carbon easy-cut steel that is also excellent in surface properties and can be manufactured inexpensively. Further, the supply of low carbon easy-cut steel which also has excellent carburization properties in addition to the above characteristics is also a subject of the present invention. Means for Solving the Problem It is well known that the state of inclusions such as sulfides has a large influence on the cutability of steel. There are many inclusions observed in steels containing C, Ti, S, N, and niobium. For example, Ti sulfide, Ti carbon sulfide, Ti carbide, Ti carbonitride, Ti nitride, Ti oxide. If it contains more Μη, there is also the presence of Μη sulfides in the chemical formula of "MnS". In addition to these, Al and Si are also present in these oxides. There are various forms of such existence, and the composition and existence form of such inclusions have a great influence on the cuttability of steel and other mechanical properties. The present inventors have filed a patent application for the invention of (6) 1247815, a low carbon sulfur free cut steel which does not contain Pb, in the prior patent application No. 2 002 - 2 63 6 8 . The easy-cut steel is characterized in that the content of C, Mn, S, Ti, Si, P, A1, 0, and N, Ti, and S satisfies the following formula (A), and the atomic ratios of Μη and S satisfy The low carbon sulfur easy-cut steel of the formula (B) and containing MnS containing Ti sulfide or/and Ti carbon sulfide.
Ti (質量 ％) /S (質量 ％) <1 ......... ( A)Ti (mass %) / S (mass %) <1 ......... (A)
Mn/S ^ 1 ......... ( B ) 該前案發明之鋼，工具壽命遠優於Pb易割鋼，並具 優良之切屑處理性。但是，該鋼於切割後之表面性狀有若 干難處。亦即已知施以加工切割時，有時會有加工面粗度 大之問題。 基質中有實質上之Ti硫化物或/及Ti碳硫化物存在 ，應會很難得到類似MnS之潤滑效果，故切割阻力上升 ，於工具刀刃生成刀瘤，切割後鋼材表面不得光澤度，使 加工面粗細劣化。而上述之「實質上之Ti硫化物或/及Ti 碳硫化物」意指，一個夾雜物中Ti硫化物Ti碳硫化物所 占面積率合計占50%以上之夾雜物，後敘之第1圖（a) 中示其若干。 因而爲解決上述問題進行探討結果得知如下之新見解 〇 (1)切割有「實質上之Ti硫化物或/及Ti碳硫化物 」存在於基質中之鋼時，於工具刀刃生成刀瘤，加工表面 之粗細劣化。 (2 )盡量抑制「實質上之T i硫化物或/及τ i碳硫化 -10- (7) 1247815 物」之生成，且使鋼中多有MnS存在，即可抑制刀瘤之 生成，得良好之加工面粗細。 (3)但是，不含Ti僅有MnS存在之鋼，超硬工具 壽命劣化。爲提升超硬工具壽命，必須添加Ti，並使「 內有Ti硫化物或/及Ti碳氮化物的實質上之MnS」存在 〇 (4 ) 「內有Ti碳化物或/及Ti碳氮化物的實質上之 MnS」可提升工具壽命而無損於MnS之擬潤滑效果。 基於上述見解，更詳細探討化學組成與夾雜物形態之 關係。結果完成下示低碳易割鋼之發明。該低碳易割鋼具 有與Pb易割鋼、複合易割鋼同等以上之被割性。而，有 關成分含量之％係質量％。 含有 C: 0.05 至不及 0.20%，Μη: 0.4 至 2.0%，S: 0·21 至 1.0%，Ti: 0.002 至 0.10°/。，p: o.ooi 至 〇·3〇%， 八1:0.2%以下，〇(氧）：0.001 至 0.03%，N: 0.0005 至 0.02%，餘係Fe及雜質所成之鋼，其特徵爲：剛中含有之 夾雜物滿足下述（i )式及（Π )式之低碳硫易割鋼。 (A + B ) /C ^ 0.8 ......... ( i ) N A ^ 5 ......... ( ii ) 其中A、B、C及Na之意義如下。 A :平行於輥軋方向之剖面1 m m2中的圓相當直徑1 μ m以上的夾雜物之中，內有T i碳化物或/及τ丨碳氮化 物的實質上之Μ n S所占之總面積。 Β :平行於輥軋方向之剖面1 mm2中圓相當直徑1 # 1Ώ -11 - (8) 1247815 以上的夾雜物之中’內無Ti碳化物、Ti碳氮化物的實質 上之Μ n S所占的總面積。 C :平行於輥軋方向之剖面1 mm2中圓相當直徑1 // m 以上之全部夾雜物所占之總面積。Mn/S ^ 1 ......... (B) The steel of the prior invention has much longer tool life than Pb easy-cut steel and has excellent chip handling properties. However, the steel has some difficulty in surface properties after cutting. That is, when the cutting is known to be applied, there is a problem that the thickness of the processed surface is large. If there is a substantial Ti sulfide or/and Ti carbon sulfide in the matrix, it should be difficult to obtain a lubricating effect similar to MnS, so the cutting resistance increases, the knife blade is formed on the tool blade, and the surface of the steel after cutting is not glossy, so that The thickness of the machined surface is degraded. The above-mentioned "substantially Ti-sulfide or/and Ti-carbon sulfide" means an inclusion having a total area ratio of Ti sulfide Ti-carbon sulfide in an inclusion of 50% or more, and is referred to as the first one. A number of them are shown in Figure (a). Therefore, in order to solve the above problems, the following new findings are obtained. (1) When a steel having a "substantial Ti sulfide or/and a Ti carbon sulfide" is present in a matrix, a knife blade is formed on the tool blade. The thickness of the machined surface is degraded. (2) Try to suppress the formation of "substantially T i sulfide or / and τ i carbon vulcanization -10 (7) 1247815", and the presence of MnS in the steel can inhibit the formation of the knife. Good processing surface thickness. (3) However, steel containing no MnS in the presence of Ti, the life of the superhard tool deteriorates. In order to improve the life of superhard tools, it is necessary to add Ti and to present "substantial MnS with Ti sulfide or/and Ti carbonitride" in 〇(4) "with Ti carbide or/and Ti carbonitride The substantial MnS" improves tool life without compromising the intended lubrication of MnS. Based on the above findings, the relationship between chemical composition and inclusion morphology is discussed in more detail. The result is shown below as the invention of low carbon easy cut steel. The low-carbon easy-cut steel has the same cutability as Pb easy-cut steel and composite easy-cut steel. However, the % of the relevant component content is % by mass. Contains C: 0.05 to less than 0.20%, Μη: 0.4 to 2.0%, S: 0·21 to 1.0%, Ti: 0.002 to 0.10°/. , p: o.ooi to 〇·3〇%, 八1: 0.2% or less, 〇(oxygen): 0.001 to 0.03%, N: 0.0005 to 0.02%, the remainder of the steel formed by Fe and impurities, characterized by : The inclusions contained in the sample satisfy the low carbon sulfur easy-cut steel of the following formula (i) and (Π). (A + B ) /C ^ 0.8 ......... (i) N A ^ 5 ... ( ii ) where A, B, C and Na have the following meanings. A: Among the inclusions having a diameter of 1 m m or more in the section 1 m m2 parallel to the rolling direction, the substantially Μ n S of the T i carbide or/and the τ 丨 carbonitride The total area. Β: section parallel to the rolling direction 1 mm2 medium circle equivalent diameter 1 # 1Ώ -11 - (8) 1247815 Among the inclusions, there is no substantial amount of Ti carbide and Ti carbonitride in the inclusions. The total area occupied. C: The total area of all the inclusions with a diameter of 1 / 2 m or more in the section 1 mm2 parallel to the rolling direction.
Na :平行於輥軋方向之剖面1 mm2中圓相當直徑1 // m以上的夾雜物之中，內有Ti碳化物或/及Ti碳氮化 物的實質上之MnS的個數。 上述低碳易割鋼，可含選自下述第一群至第三群中之 至少一群的一種以上之成分。 第一群Na: The number of substantially MnS containing Ti carbide or/and Ti carbonitride among the inclusions having a diameter of 1 mm 2 and a diameter of 1 mm 2 parallel to the rolling direction. The low carbon cut-away steel may contain one or more components selected from at least one of the first to third groups described below. First group
Se ： 0.0005 至 0.10%、Te: 0.0005 至 0.10%、Bi: 〇 · 〇 1 至 〇 · 3 °/〇、S η : 0.0 1 至 〇 · 3 %、C a : 0 · 0 0 0 1 至 0.0 1 %、 Mg·· 0.0001 至 0.005 °/。、B: 0.0002 至 0.02%及稀 土元素 :0.0005 至 0.02 % 〇 第二群Se : 0.0005 to 0.10%, Te: 0.0005 to 0.10%, Bi: 〇· 〇1 to 〇· 3 °/〇, S η : 0.0 1 to 〇· 3 %, C a : 0 · 0 0 0 1 to 0.0 1 %, Mg·· 0.0001 to 0.005 °/. , B: 0.0002 to 0.02% and rare earth elements: 0.0005 to 0.02 % 〇 second group
Cu: 0.01 至 1.0%、Ni: 0.01 至 2·0°/。、Μο: 0·01 至 0.5%、V: 0.005 至 〇.5°/〇 及 Nb: 0·005 至 0.5%。 第三群 S i : 0 .〗至 2 . 〇 % 及 c r : 0 · 0 3 至 1 . 0 %。 在此’ 「內有Ti碳化物或/及Ti碳氮化物的實質上 之Μn S」如後詳敘，指一個夾雜物中Mn S所占面積率在 5 0 %以上’而內有（共存有）Ti碳化物或/及Ti碳氮化物 之夾雜物。另一方面，「內無Ti碳化物、Ti碳氮化物的 實質上之MnS」指一個夾雜物中MnS所占面積率在5〇% (9) 1247815 以上，而內無（共存之）Ti碳化物、Ti碳氮化物之夾雜 物。又，此等「內有Ti碳化物或/及Ti碳氮化物的實質 上之MnS」及「內無Ti碳化物、Ti碳氮化物的實質上之 MnS」皆可於其中有Ti碳化物、Ti碳氮化物以外之硫化 物、碳硫化物、碳化物、氮化物等。 上述本發明之低碳易割鋼的主要特徵如下。 (1 )使C自0.0 5 %至不及0.20%，含0.21至1.0%之 S，且使Ti之含量爲0.002至0.1%。 (2 ) Ti與C、S、N及Ο結合形成硫化物、碳硫化 物、碳化物、碳氮化物及氧化物。因Ti之硫化物形成傾 向強於Μ η，容易形成T i硫化物、T i碳硫化物。但是，若 審慎考慮Mn、Ti、S及N之含量平衡，可無「實質上之 Ti碳硫化物或/及Ti硫化物」之大量生成，使「內有Ti 碳化物或/及Ti碳氮化物的實質上之MnS」及「內無Ti 碳化物、Ti碳氮化物的實質上之MnS」多有存在。 (3 )成爲上述（1 )之化學組成，且可得如上述（2 )之夾雜物形態時，存在於基質中之夾雜物在切割中軟質 化，發揮潤滑效果之「實質上之MnS」占全部夾雜物之大 半，成爲幾無該「實質上之M nS」以外的硫化物，亦即， 「實質上之Ti碳化物或/及Ti碳硫化物」之形態。此時 ，爲得良好之加工面粗細，即必須於全部夾雜物的生成量 之中幾乎全由「實質上之MnS」的生成量所占。具體而言 ，輥軋方向剖面之觀察面I mm2中圓相當直徑1 // m以上 的「實質上之MnS」的總面積，必須占圓相當直徑]# m -13- (10) 1247815 以上的全部夾雜物之總面積的八成以上。僅只此時，「實 質上之Ti碳化物或/及Ti碳硫化物」之存在所引起的工 具刀刃之刀瘤的生成可予抑制，得良好之加工面粗細。 上述「實質上之MnS」係指一個夾雜物中MnS所占 面積率在50%以上之夾雜物，包括「內有Ti碳化物或/及 Ti碳氮化物的實質上之MnS」及「內無Ti碳化物、Ti碳 氮化物的實質上之MnS」。 如上述（i)式，「占八成以上」者乃（i)式之 ’’ A + B ’’。而A及B之定義係，平行於輕軋方向之剖面 1 m m2中圓相當直徑1 // m以上的硫化物之中，「內有T i 碳化物或/及Ti碳氮化物的實質上之MnS」所占面積及「 內無Ti碳化物、Ti碳氮化物的實質上之MnS」所占面積 〇 並且，「內有Ti碳化物或/及Ti碳氮化物的實質上 之MnS」、「內無Ti碳化物、Ti碳氮化物的實質之MnS 」、「實質上之Ti硫化物或/及Ti碳硫化物」及其以外 之硫化物、碳硫化物、碳化物、氮化物、氧化物、Al2〇3 、Si02等之總面積的合計即（i )式之C。 (4)含如上述（3)之夾雜物的鋼材，易言之，幾無 「實質上之Ti硫化物或/及Ti碳硫化物」存在，含於鋼 中的夾雜物之大半係「實質上之MnS」者，若有「內有 Ti碳化物或/及ΤΊ碳氮化物的實質上之MnS」存在，於切 割溫度高之高速範圍作切割時，工具表面亦可形成硬質之 TiN膜，保護工具而得優良之工具壽命。 -14- (11) 1247815 (5 )有「內有Ti碳化物或/及Ti碳氮化物的實質上 之MnS」存在之鋼，其「實質上之MnS」，比習知JIS SUM22L至24L之複合易割鋼所含之MnS微細，個數較 多。此時’此等微細的「實質上之Mn S」成爲切割中應力 集中之起點，容易助長龜裂傳播，故可得與複合易割鋼同 等以上之切屑處理性。 (6 )有「內有Ti碳化物或/及Ti碳氮化物的實質上 之MnS」存在之鋼因熱加工性全無問題，於被割性之改善 有效的S含量可予增多，此時以連續鑄造設備等製造，亦 不招致任何障礙。又，Ti添加量少亦可充分發揮效果， 製造所須成本低，適用作廉價鋼材。 如前敘，限定合金成分之範圍，調整夾雜物之形態， 可得優良之被割性。但是，用於汽車零件之鋼材有時除被 割性以外亦期待有優良之滲碳特性。因而可知，檢視Si 及C r對於鋼之特性的影響，調整S i量、C r量，即可無 損於夾雜物之形態，因此無鋼材的被割性之劣化而改善滲 碳特性。Cu: 0.01 to 1.0%, Ni: 0.01 to 2·0°/. , Μο: 0·01 to 0.5%, V: 0.005 to 〇.5°/〇 and Nb: 0·005 to 0.5%. The third group S i : 0 . 到 to 2 . 〇 % and c r : 0 · 0 3 to 1 . 0 %. Here, the "substantial Μn S of Ti carbide or/and Ti carbonitride" is described in detail later, and the area ratio of Mn S in an inclusion is more than 50%. There are inclusions of Ti carbide or/and Ti carbonitride. On the other hand, "substantially MnS without Ti carbide and Ti carbonitride" means that the area ratio of MnS in one inclusion is 5〇% (9) 1247815 or more, and there is no (coexisting) Ti carbonization in the inside. Inclusions of Ti, carbonitride. Further, these "substantially MnS having Ti carbide or/and Ti carbonitride" and "substantially MnS having no Ti carbide or Ti carbonitride therein" may have Ti carbide therein. Sulfides, carbon sulfides, carbides, nitrides, etc. other than Ti carbonitride. The main features of the low carbon easy-cut steel of the present invention described above are as follows. (1) Let C be from 0.05% to less than 0.20%, contain 0.21 to 1.0% of S, and make the content of Ti 0.002 to 0.1%. (2) Ti combines with C, S, N and niobium to form sulfides, carbon sulfides, carbides, carbonitrides and oxides. Since the sulfide formation of Ti tends to be stronger than Μ η, it is easy to form Ti sulfide and Ti sulfide. However, if the balance of the contents of Mn, Ti, S and N is carefully considered, there is no substantial production of "substantially Ti carbon sulfides or/and Ti sulfides", so that "Ti carbides and/or Ti carbons are contained therein." The substantial MnS of the compound and the "substantial MnS without Ti carbide and Ti carbonitride" are present. (3) When the chemical composition of the above (1) is obtained, and the inclusion form as in the above (2) is obtained, the inclusions present in the matrix are softened during the dicing, and the "substantial MnS" which exhibits the lubricating effect is occupied. Most of the inclusions are in the form of sulfides other than the "substantially MnS", that is, "substantially Ti carbides or/and Ti carbon sulfides". In this case, in order to obtain a good processing surface thickness, it is necessary to occupy almost all of the amount of inclusions generated by the amount of "substantial MnS". Specifically, the total area of the "substantial MnS" with a diameter of 1 / m or more in the observation surface I mm2 in the rolling direction section must be equal to the diameter of the circle] # m -13- (10) 1247815 or more More than 80% of the total area of all inclusions. Only at this time, the formation of a knife blade of a tool blade caused by the presence of "substantially Ti carbide or/and Ti carbon sulfide" can be suppressed, and a good machined surface thickness can be obtained. The above "substantially MnS" means inclusions having an area ratio of MnS in an inclusion of 50% or more, including "substantially MnS having Ti carbide or/and Ti carbonitride" and "without The substantial MnS of Ti carbide and Ti carbonitride. As in the above formula (i), "occupy 80% or more" is the type 'i'' A + B ''. The definitions of A and B are parallel to the sulphide of a diameter of 1 m m2 in the direction of the light rolling direction, which is equivalent to a diameter of 1 // m or more. "There is essentially a T i carbide or/and a Ti carbonitride. The area occupied by MnS" and the area of "substantially no MnS of Ti carbide and Ti carbonitride", and "substantial MnS of Ti carbide or/and Ti carbonitride", "There is no substantial MnS of Ti carbide, Ti carbonitride", "Substantial Ti sulfide or/and Ti carbon sulfide" and other sulfides, carbon sulfides, carbides, nitrides, oxides The total area of the substance, Al2〇3, SiO2, etc., is the formula (i) C. (4) A steel material containing inclusions as described in (3) above, in other words, there are few "substantial Ti sulfides or/and Ti carbon sulfides", and most of the inclusions contained in steel are "substance." In the case of "MnS", if there is "substantial MnS with Ti carbide or/and niobium carbonitride", when the cutting temperature is high, the surface of the tool can also form a hard TiN film. Excellent tool life for protecting tools. -14- (11) 1247815 (5) A steel having "substantial MnS with Ti carbide or/and Ti carbonitride", which is "substantially MnS", which is better than the conventional JIS SUM22L to 24L. The MnS contained in the composite easy-cut steel is fine and the number is large. At this time, the fine "substantial Mn S" becomes the starting point of the stress concentration during the cutting, and it is easy to promote the crack propagation, so that the chip handling property equal to or higher than that of the composite easy-cut steel can be obtained. (6) Steel having "substantial MnS with Ti carbide or/and Ti carbonitride" has no problem in hot workability, and the S content which is effective in improving the cuttability can be increased. Manufactured in continuous casting equipment, etc., does not cause any obstacles. Further, when the amount of Ti added is small, the effect can be sufficiently exerted, and the cost required for production is low, and it is suitable for use as an inexpensive steel material. As described above, the range of the alloy composition is limited, and the shape of the inclusions is adjusted to obtain excellent cuttability. However, steels used for automobile parts are expected to have excellent carburizing characteristics in addition to the cuttability. Therefore, it is understood that the influence of Si and Cr on the properties of steel and the amount of S i and the amount of Cr can be adjusted without impairing the form of the inclusions. Therefore, the carburization property is improved without deterioration of the cut property of the steel.
Si及Cr固溶於沃斯田體中，提高鋼之淬火性，可增 大滲碳處理時之滲碳深度及滲碳層之硬度。Si、C r以外 能提高淬火性之元素尙有Μη、Mo、P等。但是，從被割 性、熱加工性之觀點，Μη含量必須相對於S量係充足量 ’必須大量添加。此時爲提升淬火性，進一步添加Μη僅 架高成本。又，Mo於提高鋼之淬火性亦有效，但因Mo 比Si、Cr貴，添加可得同等效果的相當量之Mo則製造 (12) 1247815 成本加大。P亦具相同效果，但添加則鋼材本身之硬度急 遽上升而被割性劣化。但是，無材料成本之拘束時，不妨 在無損於被割性、機械性質之範圍以此等元素添加。唯欲 無損於被割性，並廉價製造時，宜用s i及Cr作爲滲碳特 性改善成分。 【實施方式】 1 .有關「內有Ti碳化物或/及Ti碳氮化物的實質上之 Μ n S」Si and Cr are solid-solubilized in the Worth field to improve the hardenability of the steel and increase the carburization depth and the hardness of the carburized layer during carburizing. Other elements such as Si and Cr which improve hardenability include Μ, Mo, P, and the like. However, from the viewpoint of cuttability and hot workability, the content of Μη must be sufficient relative to the amount of S. At this time, in order to improve the hardenability, further addition of Μη is only costly. Further, Mo is also effective in improving the hardenability of steel, but since Mo is more expensive than Si and Cr, it is produced by adding a considerable amount of Mo which can obtain the same effect (12) 1247815. P also has the same effect, but when added, the hardness of the steel itself rises sharply and the cut property deteriorates. However, when there is no material cost constraint, it may be added in such a way that it does not impair the severability and mechanical properties. It is advisable to use s i and Cr as carburizing properties to improve the cut properties and to manufacture them at low cost. [Embodiment] 1. "Substantially Μ n S having Ti carbide or/and Ti carbonitride therein"
Ti與S、C、Ν、〇結合形成TiS及Ti4C2S2之化學式 的Ti硫化物、Ti碳硫化物，TiC、Ti ( CN ) 、TiN、TiO 之化學式的Ti碳化物、Ti碳氮化物、Ti氮化物、Ti氧化 物之Ti系夾雜物。又，有時Ti固溶於MnS中以（Μη， Ti ) S存在，但因該固溶於MnS中之Ti係微量，該硫化 物實質上係MnS。 另一方面，有時Ti不固溶於MnS中，在一個夾雜物 中與MnS明確相分離而存在。該Ti係以TiC或/及Ti(C ，N )之形式，亦即以與MnS組成明顯不同之形式存在， 其存在形態有，存在於一個硫化物周圍附近者，以包圍在 MnS中之形式存在者等多種。 第1圖係存在於含Ti之易割鋼中的夾雜物之示意圖 ，（a )係比較例之易割鋼，（b )係本發明之易割鋼。第 1圖（a )之鋼多有，單獨存在之Ti的硫化物、碳硫化物 、或在一個夾雜物中與MnS共存時Ti之硫化物、碳硫化 -16- 1247815 (13) 物所占面積率亦達50%以上，實質上可視爲丁丨之硫化物 、碳硫化物之夾雜物，亦即前敘之「實質上之Ti硫化物 或/及Ti碳硫化物」存在。另一方面，第1圖（b)的本 發明鋼，多有T i碳化物或/及T i碳氮化物存在於μ n S之 外周部或包圍於內部的夾雜物，亦即「內有Ti碳化物或/ 及Ti碳氮化物的實質上之MnS」及「內無Ti碳化物或/ 及Ti碳氮化物的實質上之MnS」存在。 上述第1圖（b )之鋼，Ti硫化物、Ti碳硫化物或Ti 碳化物、T i碳氮化物、T i氮化物、T i氧化物及此等以外 之夾雜物與MnS明確相分離而包含在內時，MnS所占面 積率50 %以上者實質上仍判定爲一個MnS，亦即「實質上 之Mn S」。反之’ 一個夾雜物中，此等Ti系夾雜物或其 它成分所成之氧化物、氮化物、碳化物等所占面積率在 5 0%以上之夾雜物則非「實質上之MnS」，而實質上判定 爲一個Ti系夾雜物、其它成分所成之氧化物、氮化物、 碳化物等。 上述MnS之中，尤其Ti碳化物或/及Ti碳氮化物與 MnS明確相分離包含於內，MnS所占面積率50°/。以上之夾 雜物定義爲「內有Ti碳化物或/及Ti碳氮化物的實質上 之MnS」。另一方面，「內無Ti碳化物、Ti碳氮化物的 實質上之MnS」乃，Ti碳化物及Ti碳氮化物除外之上述 Ti系夾雜物，或其它成分所成之氧化物、氮化物、碳化 物等夾雜物與MnS在一個夾雜物中明確相分離存在，且 MnS所占面積率50%以上，實質上發揮MnS之作用的 -17- (14) 1247815Ti combines with S, C, niobium and tantalum to form Ti sulfides of TiS and Ti4C2S2, Ti carbon sulfides, Ti carbides of TiC, Ti(CN), TiN, TiO, Ti carbonitrides, Ti nitrogens Ti-based inclusions of compounds and Ti oxides. Further, although Ti is solid-dissolved in MnS, it is present as (Μη, Ti) S, but since the Ti is solid-dissolved in MnS, the sulfide is substantially MnS. On the other hand, in some cases, Ti is not dissolved in MnS, and is present in an inclusion and is clearly separated from MnS. The Ti is in the form of TiC or/and Ti(C,N), that is, in a form substantially different from the composition of MnS, and exists in a form existing around a sulfide to surround the MnS. There are many kinds of people. Fig. 1 is a schematic view showing inclusions present in a free-cutting steel containing Ti, (a) a free-cutting steel of a comparative example, and (b) an easy-cut steel of the present invention. The steel of Fig. 1(a) is mostly composed of sulfides, carbon sulfides, or sulfides of Ti in the presence of MnS in one inclusion, and carbon sulfide--16-1447815 (13) The area ratio is also over 50%, which can be regarded as the inclusion of sulphide and carbon sulphide in Ding, which is the existence of "substantially Ti sulphide or / and Ti carbon sulphide". On the other hand, in the steel of the present invention of Fig. 1(b), there are many T i carbides or/and Ti carbon nitrides present in the outer periphery of the μ n S or inclusions inside, that is, The substantial MnS" of the Ti carbide or/and the Ti carbonitride and the "substantial MnS of the Ti carbide or/and the Ti carbonitride" are present. The steel of Fig. 1(b) above, Ti sulfide, Ti carbon sulfide or Ti carbide, Ti carbonitride, Ti nitride, Ti oxide and other inclusions are clearly separated from MnS When included, the area ratio of MnS of 50% or more is still substantially determined as one MnS, that is, "substantially Mn S". On the other hand, in an inclusion, inclusions having an area ratio of 50% or more of oxides, nitrides, and carbides formed by such Ti-based inclusions or other components are not "substantially MnS". It is substantially determined as a Ti-based inclusion, an oxide, a nitride, or a carbide formed by other components. Among the above MnS, in particular, Ti carbide or/and Ti carbonitride is clearly phase-separated from MnS, and the area ratio of MnS is 50°/. The above inclusions are defined as "substantially MnS with Ti carbides or/and Ti carbonitrides". On the other hand, "substantially MnS without Ti carbide and Ti carbonitride" is the above-mentioned Ti-based inclusions other than Ti carbide and Ti carbonitride, or oxides and nitrides formed by other components. The inclusions such as carbides and MnS are clearly separated from each other in an inclusion, and the area ratio of MnS is 50% or more, and -17-(14) 1247815 which substantially functions as MnS.
MnS，以及上述Ti系夾雜物，其它成分所成之氧化物、 氮化物、碳化物等夾雜物全然不存在之MnS。易言之，「 內有Ti碳化物或/及Ti碳氮化物的實質上之MnS」與「 內無Ti碳化物、Ti碳氮化物的實質上之MnS」合計，表 實質上可視爲MnS之夾雜物（上述之「實質上之MnS」 )的合計，此外之夾雜物係Ti硫化物、Ti碳硫化物、Ti 碳化物、Ti碳氮化物、Ti氮化物、Ti氧化物之Ti系夾雜 物及其它元素構成之氧化物、碳化物及氮化物等。 前敘一個夾雜物中 MnS、Ti系夾雜物所占之面積率 ，可對於得自切割試驗之圓棒所切出之微試片以ΕΡΜΑ ( 電子束微分析儀）、EDX (能散X射線分析裝置）進行面 分析及定量分析而得。又，鋼中之「內有Ti碳化物或/及 Ti碳氮化物的實質上之MnS」，「內無Ti碳化物、Ti碳 氮化物的實質上之MnS」，及其它夾雜物亦可由同樣方法 確認，其總面積、個數亦可由圖像解析等手法測定。此際 ，以觀察視野面積合計超過1 mm2之多數視野作測定時， 將各夾雜物之總面積及個數換算成每1 mm2之平均總面積 、平均個數即可。 2.使（A + B)/C20.8 之理由 上述（i )式之A係平行於輥軋方向的剖面1 m m2中 圓相當直徑1 // m以上之夾雜物中，「內有ΤΊ碳化物或/ 及Ti碳氮化物的實質上之MnS」所占之總面積，B係， 平行於輥軋方向之剖面1 nim2中圓相當直徑1 " m以上的 -18- (15) 1247815 夾雜物中，「內無Ti碳化物、Ti碳氮化物的實質上之 MnS」所占的總面積。在此，「圓相當直徑」指，由上述 之圖像解析等手法求出的一個夾雜物之面積’換算成同面 積之圓時的直徑。「圓相當直徑1 // m以上」之限定，乃 因不及1 // m之夾雜物，於被割性幾無影響。 上述（i)式示，該人與B合計，圓相當直徑 以上之全部夾雜物須占總面積的80%以上。在該範圍即可 得良好之被割性，而90%以上更佳。又，如前敘，A及B 所表以外之夾雜物指單獨存在之氮化物 '碳化物、氧化物 、「實質上之Ti硫化物或/及Ti碳硫化物」等。易言之 ，（i )表示「實質上之MnS」以外的此等夾雜物之總面 積，占全部夾雜物之總面積（（i )式之C )不及20%。 該總面積不及10%則更佳。 爲提升被割性於含大量S之鋼添加Ti，則因Ti比 Μη形成硫化物之傾向強，容易形成Ti硫化物、Ti碳硫化 物。但是，本發明規定之（i )式，係以Ti之添加爲前提 ，並圖Ti硫化物、Ti碳硫化物的生成之抑制。此乃由於 Ti硫化物、Ti碳硫化物在切割中妨礙MnS之擬潤滑效果 。MnS之擬潤滑效果受損，則工具與被割材料間之摩擦力 應會上升，於工具刀刃生成刀瘤使加工面粗細劣化。因此 ，Ti硫化物、Ti碳硫化物之生成須予抑制。易言之，如 (i )式所規定，使單獨存在的「實質上之Ti硫化物或/及 Ti碳硫化物」幾不存在於鋼中，而含於鋼中之夾雜物的 80%以上爲「實質上之MnS」，即可於切割中得擬潤滑效 (16) 1247815 果0 如此，限定於本發明規定之鋼組成範圍，且滿足（i )式時’加工切割中可得與習知P b易割鋼、複合易割鋼 冋寺以上之良好加工面粗細。另一方面，即使在本發明規 定之化學組成範圍內，若不滿足（i )式，仍不得良好之 被割性。 3.使NA2 5之理由 上述（ii )式之Na係「平行於輥軋方向之剖面lmm2 中圓相當直徑1 // m以上的夾雜物中，內有Ti碳化物或/ 及Ti碳氮化物的實質上之MnS之個數」。該「內有Ti 碳化物或/及Ti碳氮化物的實質上之MnS」指，如上述， 一個夾雜物中 MnS所占面積率50%以上者。而該「內有 Ti碳化物或/及Ti碳氮化物的實質上之MnS」因實質上無 損於擬潤滑效果，不易形成刀瘤，被切割材料之加工面粗 細不劣化。 又，有「內有Ti碳化物或/及Ti碳氮化物的實質上 之MuS」存在的鋼，使用超硬工具於超過i〇〇m/min之高 速範圍切割後，詳細觀察該工具表面，則可知工具表面有 TiN之形成。切割中與被割材料接觸之工具表面，Ti系夾 雜物隨摩擦所致之升溫應會反應、變質，形成厚度數// m 至數十// m呈層狀之硬質TiN。其存在可由對於切割結束 後工具表面之碳系污染物（油分等）以Ar濺鍍等去除之 工具表面，用 AES (奧杰電子能譜儀）、ΕΡΜΑ (電子束 (17) 1247815 微分析儀）作面分析及點分析而確認。以此，附著於工具 之TiN的表面積係被切割材料與工具之接觸面積的：[〇至 80%，其餘係切割加工時附著之MnS、Fe或無附著物之工 ^ 具原表面。因該硬質TiN之形成於工具表面，工具由於熱 - 擴散磨損、硬質夾雜物所致之機械磨損受到抑制，應可得 - 較之習知S易割鋼、含Pb之複合易割鋼格外優良之工具 壽命。 爲得如此效果，宜使「內有Ti碳化物或/及Ti碳氮 φ 化物的實質上之MnS」，在輥軋方向剖面之觀察面1mm2 中有5個以上存在，1 〇個以上更佳。 另一方面，即使在本發明規定之化學組成的範圍內， 若不滿足（i i )式仍不得良好之被割性。 添加Ti並成爲滿足（i )式及（ii )式之夾雜物形態 的鋼，有非常微細之MnS存在。亦即MnS之個數極多。 該微細之MnS於切割時發揮生成之切屑的應力集中點之 作用，因助長切屑內的龜裂傳播而提升切屑處理性。 · 以上，要者爲，使「內有Ti碳化物或/及Ti碳氮化 物的實質上之MnS」安定存在於鋼中，輥軋方向剖面之觀 察面1mm2中有5個以上，輥軋方向剖面之觀察面1mm2 · 中「內有Ti碳化物或/及Ti碳氮化物的實質上之MnS」 及「內無Ti碳化物、Ti碳氮化物的實質上之MnS」的總 ·- 面積合計占全部夾雜物總面積之八成以上，則如上述，可 ％ 得與Pb易割鋼、複合易割鋼同等以上之工具壽命、加工 面粗細及切屑處理性。爲更安全實現如此之夾雜物形態， -21 - (18) 1247815 以連續鑄造等廉價製造被割性優之鋼材，必須考慮Μη、 Ti、S及Ν之含量的均衡。具體宜係如下。 (a ) Ti ( 〇/〇 ) /S ( % ) ^0.25 相對於S量多以Ti添加時，亦即質量比Ti/S超過 0.25時，即多有Ti硫化物、Ti碳硫化物存在。結果無法 滿足（i )式，有損於Mn S之擬潤滑效果。此時切割阻力 上升’有於工具刀刃容易形成刀瘤之傾向，以致加工切割 埘表面粗細劣化，加工精度變差。 反之，相對於S量以微量之Ti添加時，即其質量比 Ti/S在0.25以下時，Ti形成Ti碳化物及Ti碳氮化物， 「實質上之Ti硫化物或/及Ti碳硫化物」幾不單獨存在 〇 T i碳北物、T i碳氮化物係以種種形態析出，有時係 以內含於一個MuS之形態存在。並且，含「內有Ti碳化 物或/及Ti碳氮化物的實質上之MuS」之鋼，使用超硬工 具於高速範圍切割時可得優良之工具壽命。易言之，爲抑 制單獨存在的「實質上之Ti硫化物或/及Ti碳硫化物」 之生成，將Ti ( %) /S ( %)調整於0.25以下即可。 (b ) Μη及S之量的原子比〔Mn〕/〔 S〕^ j S係熱加工時會造成裂痕之元素。但是，原子比，亦 即原子數（莫耳數）比〔Μη〕/〔 S〕- 1之適當組成若能 維持，則Μ η以Μ n S結晶，故即使例如T j ( % ) / s ( % ) $ 0 · 2 5，熱加工性亦無問題。又’若在該範圍，即使例如 以連續鑄造之製造爲前提，亦可多添加S以使熱加工性無 -22- (19) 1247815 任何問題，增加MnS以有效改善被割性，並且即使S含 量高亦無損於（i )式及（ii )式所表之夾雜物形態。 〔Mn〕/〔 S〕<1時，若不添加超過s量之Ti則多有 FeS固溶於MnS及TiS之硫化物成爲主體，無法改善熱加 工性。而即使〔Mn〕/〔 S〕< 1時，在超過S量之範圍添 加Ti，則可改善熱加工性。但是，此時因Ti之硫化物生 成傾向大於Μη，主要之生成硫化物並非MnS，而係以比 Μ n S硬之T i硫化物或T i碳硫化物爲主體。此時，如前敘 於切割時工具與被割材料間不得軟質硫化物之擬潤滑效果 ，切割阻力上升，加工面粗細劣化。易言之，使Μη與S 量的原子比〔Μη〕/〔 S〕2 1，仍係伴隨MnS提升切割性 之效果，同時謀取良好熱輥軋性的有利條件。 (c ) Ti ( % ) /N ( % ) ^1.35 本發明的易割鋼之重大特徵係，含有「內有Ti碳化 物或/及Ti碳氮化物的實質上之MnS」。當Ti ( % ) /N ( °/〇 ) $ 1 .35時，有時不得充分之「內有Ti碳化物或/及Ti 碳氣化物的貫質上之MnS」。此時，因幾乎所有添加之 Ti於凝固之早期階段以TiN結晶，應無法確保可形成r 內有Ti碳化物或/及Ti碳氮化物的實質上之MnS」的充 分之Ti。因此，Ti ( % ) /N ( % )宜在1 .3 5以上，爲更安 定得「內有Ti碳化物或/及Ti碳氮化物的實質上之MnS 」，使Ti ( % ) /N ( % )爲1 .5以上即可。 4 .限定化學組成之理由 -23- (20) 1247815 以下連同各成分之作用效果，說明本發明中限定化學 組成之理由。 C : 〇 · 〇 5 % 至不及 〇 · 2 0 % C係於被割性大有影響之重要元素。C含量達0.20% 以上則鋼材強度提高，被割性劣化，故不適於重視被割性 之用途的鋼材。但是，不及0.05 %之鋼材則過軟，切割中 引起擠裂，加快工具磨損，切工面粗度亦變大。故C之恰 當含量係0.05%至不及0.20%。爲得更佳被割性，C量之 更恰當範圍係0.0 7至0.1 8 %。 Μη : 0.4 至 2.0〇/〇 Μη連同S形成硫化物系夾雜物，係於被割性大有影 響之重要元素。不及0.4%則不足成爲硫化物之絕對量， 不得滿意之被割性。又，Μη係可提高鋼之淬火性的元素 ，故爲得優良之滲碳特性宜提高其含量。但因Μη連同S 形成MnS，含多量S之本發明鋼即須含多量之Μη。爲提 高滲碳特性而添加Μη則Μη含量架高，於製造成本不佳 。故以2.0%爲Μη量之上限。若超過2.0%則鋼材強度上 升而切割阻力變大，工具壽命下降。更爲切割阻力之減降 、工具壽命之提升、切屑處理性之提升、加工面粗細之提 升、熱加工性之改善，與S量之關係重要。爲確保此等性 能以使Μ η含量在0.6至1 · 8 %爲佳。 S : 0 · 2 1 至].0 0/〇 S係連同Μη形成硫化物有助於被割性之改善的元素 。由於MnS之被割性提升效果隨其生成量提升，故含量 -24- (21) 1247815 之選定很重要。不及〇 ·2 1 %則不得足量之硫化物系夾雜物 ，不得滿意之被割性。另一方面，通常若S量超過0.35% 則熱加工性惡化，助長鋼块中央部的S偏析’鍛造時弓丨發 破裂，維持恰當組成則其上限可提高至1 ·〇%。爲以MnS 提升被割性，以更添加S爲佳，0.3 5 %以上則佳。爲更改 善則以超過0.40%之含量更佳。但是，過剩添加則良率變 差以致成本上升，故S含量之較佳上限係0.70%。MnS, and the above-mentioned Ti-based inclusions, MnS in which inclusions such as oxides, nitrides, and carbides formed by other components are not present at all. In other words, "the substantial MnS of Ti carbide or/and Ti carbonitride" is combined with "substantially MnS without Ti carbide and Ti carbonitride", and the table can be regarded as MnS. The total amount of inclusions (the above-mentioned "substantially MnS"), and the inclusions are Ti-based inclusions of Ti sulfide, Ti carbon sulfide, Ti carbide, Ti carbonitride, Ti nitride, and Ti oxide. Oxides, carbides and nitrides formed by other elements. The area ratio of MnS and Ti-based inclusions in an inclusion can be described as ΕΡΜΑ (electron beam microanalyzer) and EDX (energy dispersive X-ray) for the micro-samples cut from the round bar of the cutting test. The analysis device is obtained by performing surface analysis and quantitative analysis. Further, in the steel, "there is substantially MnS of Ti carbide or/and Ti carbonitride", "substantially MnS without Ti carbide and Ti carbonitride", and other inclusions may be the same. The method confirms that the total area and the number of the samples can also be determined by image analysis and the like. In this case, when measuring a field of view with a total field of view exceeding 1 mm2, the total area and number of each inclusion are converted into an average total area and an average number per 1 mm2. 2. Reasons for (A + B)/C20.8 The above-mentioned formula (i) is parallel to the cross-section of the rolling direction 1 m m2 and the inclusions having a diameter of 1 / m or more in the circle are "inside" The total area of the MnS" of the carbide or / and Ti carbonitride, B system, the section parallel to the rolling direction 1 nim2 in the middle circle equivalent to the diameter of 1 " m -18- (15) 1247815 In the inclusions, the total area occupied by "the substantially no MnS of Ti carbide and Ti carbonitride". Here, the "circle-equivalent diameter" refers to the diameter when the area of one of the inclusions obtained by the above-described image analysis method is converted into a circle of the same area. The limit of "a circle with a diameter of more than 1 // m" is less than the inclusion of 1 // m, and has little effect on the cut. In the above formula (i), the person and B together, all the inclusions having a diameter equal to or larger than the diameter must account for 80% or more of the total area. In this range, good cuttability can be obtained, and more than 90% is better. Further, as described above, inclusions other than those listed in A and B refer to nitrides carbides, oxides, "substantial Ti sulfides or/and Ti carbon sulfides" which are present alone. In other words, (i) indicates the total area of such inclusions other than "substantially MnS", which is less than 20% of the total area of all inclusions (C of formula (i)). The total area is less than 10%, which is better. In order to improve the cutability of Ti added to a steel containing a large amount of S, Ti tends to form a sulfide more than Μη, and it is easy to form a Ti sulfide or a Ti carbon sulfide. However, the formula (i) prescribed in the present invention is based on the premise that Ti is added, and the formation of Ti sulfide and Ti carbon sulfide is suppressed. This is because Ti sulfide and Ti carbon sulfide hinder the intended lubrication of MnS during cutting. If the intended lubrication effect of MnS is impaired, the friction between the tool and the material to be cut should increase, and the blade surface of the tool blade will deteriorate the thickness of the machined surface. Therefore, the formation of Ti sulfide and Ti carbon sulfide should be suppressed. In other words, as defined in the formula (i), the "substantial Ti sulfide or/and Ti carbon sulfide" that exists alone is not present in the steel, but more than 80% of the inclusions contained in the steel. For "substantial MnS", it can be used to obtain the lubricating effect in the cutting (16) 1247815. The result is limited to the steel composition range specified in the invention, and the formula (i) is satisfied. Know the P b easy to cut steel, composite easy to cut steel 冋 temple above the good processing surface thickness. On the other hand, even within the chemical composition range specified by the present invention, if the formula (i) is not satisfied, good cuttability is not obtained. 3. Reasons for NA2 5 The Na system of the above formula (ii) "in parallel with the cross-section of the rolling direction lmm2, the inclusions having a diameter of 1 / m or more in the circle have Ti carbide or / and Ti carbonitride The number of MnS in essence." The "substantially MnS having Ti carbide or/and Ti carbonitride therein" means that, as described above, the area ratio of MnS in one inclusion is 50% or more. Further, the "substantially MnS having Ti carbide or/and Ti carbonitride" does not substantially impair the intended lubricating effect, and it is difficult to form a knife, and the processed surface of the material to be cut does not deteriorate. Further, there is a steel in which "substantially MuS having Ti carbide or/and Ti carbonitride" exists, and the surface of the tool is observed in detail after cutting with a superhard tool at a high speed range exceeding i〇〇m/min. It can be seen that the surface of the tool has the formation of TiN. On the surface of the tool that is in contact with the material to be cut during the cutting, the temperature rise of the Ti-based inclusions with friction should be reacted and deteriorated to form a hard TiN having a thickness of from /m to tens of/m. It can be removed from the surface of the tool by Ar sputtering or the like for carbon-based contaminants (oil, etc.) on the surface of the tool after cutting, using AES (Aojie Electron Spectrometer), ΕΡΜΑ (Electron Beam (17) 1247815 Microanalyzer ) Confirmation by face analysis and point analysis. Thus, the surface area of the TiN attached to the tool is the contact area of the material to be cut by the tool: [〇 to 80%, and the rest of the surface is MnS, Fe or no deposit attached to the original surface. Because the hard TiN is formed on the surface of the tool, the tool is inhibited by thermal-diffusion wear and mechanical wear caused by hard inclusions, which should be available - superior to the conventional S-cut steel and Pb-containing composite easy-cut steel. Tool life. In order to achieve such an effect, it is preferable to have "substantially MnS having Ti carbide or/and Ti carbonitride φ compound", and there are five or more of the observation surface 1 mm2 in the rolling direction section, and more preferably one or more. . On the other hand, even within the range of the chemical composition prescribed by the present invention, good cutability is not obtained if the formula (i i ) is not satisfied. Ti is added and becomes a steel satisfying the form of inclusions of the formulas (i) and (ii), and very fine MnS exists. That is to say, the number of MnS is extremely large. This fine MnS acts as a stress concentration point of the generated chips during cutting, and promotes chip handling property by promoting crack propagation in the chips. In the above, it is necessary to stabilize the "substantial MnS of Ti carbide or/and Ti carbonitride" in the steel, and there are five or more of the observation surface 1 mm2 in the rolling direction section, and the rolling direction The total surface area of the observation surface of the section 1 mm2 · "the substantial MnS of Ti carbide or / and Ti carbonitride" and the "substantial MnS of no Ti carbide and Ti carbonitride" If it accounts for 80% or more of the total area of all inclusions, as described above, the tool life, processing surface thickness, and chip handling property equivalent to Pb easy-cut steel and composite easy-cut steel can be obtained. In order to achieve such an inclusion form more safely, -21 - (18) 1247815 It is necessary to consider the balance of the contents of Μη, Ti, S and Ν by inexpensively producing a steel having excellent cuttability such as continuous casting. Specifically, it should be as follows. (a) Ti ( 〇 / 〇 ) / S ( % ) ^ 0.25 When Ti is added with respect to the amount of S, that is, when the mass ratio Ti/S exceeds 0.25, there are many Ti sulfides and Ti carbon sulfides. The result is that the formula (i) cannot be satisfied, which is detrimental to the intended lubrication effect of Mn S. At this time, the cutting resistance rises. The tool blade tends to form a knob, so that the thickness of the surface of the machined cutting is deteriorated, and the machining accuracy is deteriorated. On the other hand, when a small amount of Ti is added with respect to the amount of S, that is, when the mass ratio Ti/S is 0.25 or less, Ti forms Ti carbide and Ti carbonitride, "substantially Ti sulfide or/and Ti carbon sulfide. The 〇T i carbon north and the T i carbonitride are precipitated in various forms, and sometimes exist in the form of a MuS. Further, a steel containing "substantially MuS having Ti carbides or/and Ti carbonitrides" can provide excellent tool life when cut at a high speed range using a superhard tool. In other words, in order to suppress the formation of "substantially Ti sulfide or/and Ti carbon sulfide" which is present alone, it is sufficient to adjust Ti (%) / S (%) to 0.25 or less. (b) The atomic ratio [Mn] / [ S ] ^ j S of the amount of Μη and S is an element which causes cracks during hot working. However, if the atomic ratio, that is, the atomic number (mole number) ratio [Μη] / [S]-1, the proper composition can be maintained, Μη crystallizes as Μ n S, so even if, for example, T j ( % ) / s ( % ) $ 0 · 2 5, no problem with hot workability. Further, if it is in this range, even if, for example, the production of continuous casting is premised, S may be additionally added so that hot workability is not -22-(19) 1247815, and MnS is increased to effectively improve the cut property, and even S The high content also does not impair the inclusion morphology of the formulas (i) and (ii). When [Mn]/[S]<1, if a Ti exceeding the amount of s is not added, a sulfide containing FeS which is solid-dissolved in MnS and TiS is mainly used, and the hot workability cannot be improved. On the other hand, even when [Mn] / [S] < 1 is added, when Ti is added in a range exceeding the amount of S, hot workability can be improved. However, at this time, the sulfide generation tendency of Ti is larger than that of Μη, and the main sulfide formation is not MnS, but is mainly composed of Ti sulfide or Ti hydrocarbon sulfide which is harder than Μ n S . At this time, as described above, the lubricating effect of the soft sulfide is not allowed between the tool and the material to be cut, the cutting resistance is increased, and the thickness of the machined surface is deteriorated. In other words, the atomic ratio [Μη]/[S]2 1 of the amount of Μη to S is still accompanied by the effect of improving the cutting property of MnS, and at the same time, it is advantageous for good hot rolling properties. (c) Ti (%) / N ( % ) ^ 1.35 The significant feature of the easy-cut steel of the present invention is "substantially MnS having Ti carbide or/and Ti carbonitride therein". When Ti (%) / N ( ° / 〇 ) $ 1.35, there may not be sufficient "the internal MnS of Ti carbide or / and Ti carbon gasification". At this time, since almost all of the added Ti is crystallized by TiN in the early stage of solidification, it is impossible to ensure sufficient Ti which can form substantially MnS" of Ti carbide or/and Ti carbonitride in r. Therefore, Ti (%) / N (%) is preferably above 1.3, which is more stable "substantial MnS with Ti carbide or / and Ti carbonitride", so that Ti (%) / N (%) is 1.5 or more. 4. Reasons for Limiting Chemical Composition -23- (20) 1247815 The reason for limiting the chemical composition in the present invention will be described below in conjunction with the effects of the respective components. C : 〇 · 〇 5 % As far as 〇 · 20% C is an important element that has a large impact on the cut. When the C content is 0.20% or more, the strength of the steel material is increased and the cut property is deteriorated, so that it is not suitable for a steel material that is used for the purpose of cutting. However, less than 0.05% of the steel is too soft, causing cracking during cutting, accelerating the wear of the tool, and the thickness of the cut surface is also increased. Therefore, the proper content of C is 0.05% to less than 0.20%. For better cut, the more appropriate range of C is 0.0 7 to 0.1 8 %. Μη : 0.4 to 2.0〇/〇 Μη Together with S to form sulfide-based inclusions, it is an important element that has a large impact on the cut. Less than 0.4% is not enough to be the absolute amount of sulfide, and it is not satisfactory to be cut. Further, since the Μη system can improve the hardenability of the steel, it is preferable to increase the content of the carburizing property. However, since Μη and S form MnS, the steel of the present invention containing a large amount of S must contain a large amount of Μη. In order to improve the carburization characteristics, the addition of Μη is high in the content of Μη, and the manufacturing cost is not good. Therefore, 2.0% is the upper limit of the amount of Μη. If it exceeds 2.0%, the strength of the steel rises and the cutting resistance becomes large, and the tool life is lowered. The reduction in cutting resistance, the improvement in tool life, the improvement in chip handling, the improvement in the thickness of the machined surface, and the improvement in hot workability are important in relation to the amount of S. To ensure this performance, the Μη content is preferably from 0.6 to 1.8 %. S : 0 · 2 1 to ]. 0 0 / 〇 S is an element that forms a sulfide with Μη to help improve the cut. Since the effect of the cut-off of MnS increases with the amount of production, the selection of the content -24-(21) 1247815 is important. Insufficient 〇 · 2 1 % is not sufficient for sulfide inclusions, and may not be satisfactorily cut. On the other hand, when the amount of S exceeds 0.35%, the hot workability is deteriorated, and the S segregation in the center portion of the steel block is promoted to break the bow, and the upper limit can be increased to 1 · 〇 %. In order to improve the cut property with MnS, it is preferable to add S more, and 0.35% or more is preferable. It is better to change the amount of goodness by more than 0.40%. However, if the excess is added, the yield is deteriorated so that the cost rises, so the upper limit of the S content is 0.70%.
Ti: 0.0002 至 0.10%Ti: 0.0002 to 0.10%
Ti係連同N、C形成Ti碳化物或/及Ti碳氮化物， 使內含此等之 MnS存在於鋼中的重要必須元素。如上述 ，鋼中若有「內有Ti碳化物或/及Ti碳氮化物的實質上 之MnS」存在，則使用超硬工具高速切割時之工具壽命大 大提升。爲使如此之MnS存在，須含0.002%以上，爲使 此等安定分散於鋼中，無加工面粗細之劣化，並得良好之 工具壽命，Ti含量與S、N的含量之均衡須加考慮。又若 Ti含量超過0.10%，則因鋼中有「實質上之Ti硫化物或/ 及Ti碳硫化物」存在，加工切割時加工面粗細變差。故 Ti以0· 10%爲上限。爲更安定得優良之加工面粗細，Ti 含量以在〇 · 〇 8 %以下爲佳。不及〇 . 〇 3 %則又更佳。 另一方面，Ti含量不及0.002 %時，無法生成足以提 升工具壽命之量的「內有Ti碳化物或/及Ti碳氮化物的 實質上之MnS」。爲更切實生成該MnS，改善超硬工具壽 命宜含超過0.01%之丁1。 P : 0.00 1 至 0.3 0% -25- (22) 1247815 P提高鋼之淬火性，同時提高強度。爲得該效果，宜 含0.001%以上。又，若在0.30%以下則無被割性之劣化， 可確保淬火性及強度，含量超過〇 . 3 0 %則強度過高，不只 被割性劣化’亦助長鋼块之偏析，熱加工性劣化。因此’ 使P含量爲0.001至0.30%。而爲安定維持良好之被割性 及強度，較佳含量係〇 . 〇 〇 5至0.1 3 %。 A1: 0.2%以下（亦可不添加） A1係用作強去氧元素，若在〇.2 %以下則亦可含有。 但經去氧生成之氧化物係硬質，含量超過0.2%則大量生 成硬質氧化物，被割性劣化。因此，更佳者爲0.1 %以下 。又，能以C、Μη添加而充分去氧時，亦可不添加A1， 其含量可係0.002%以下之雜質程度。、 0(氧）：0·001 至 0.03% 本發明鋼中氧之效果隨去氧狀態可不受損，使其含恰 當量之氧，則固溶於MnS中防止MnS因輥軋延伸，改善 機械性質之各向異性。並亦於被割性、熱加工性、S偏析 之改善有效。但若超過0.03 %則熔製時會導致引發耐火物 之劣損等缺失。故氧含量係使之在0 · 0 0 1至0 · 0 3 %的範圍 。爲恰當得上述效果，更佳範圍係0 · 0 0 1 5至0.0 1 %。 N: 0.0005 至 0.02% N容易連同Al、Ti形成硬質氮化物。此等氮化物於 晶粒之微細化有效。但隨此等氮化物之大量存在工具磨損 容易加快，使被割性劣化。本發明鋼中因以Ti爲必要成 分添加，N含量愈低愈佳，爲得上述效果，使之含 -26- 1247815 (23) 0.0 00 5 %以上。另一方面，N含量過剩則生成粗大 ，有損及被割性之虞，故使N之上限爲0.0 2 %。爲 佳之被割性，N量之上限以 0 · 0 1 5 %爲佳。又，本 係以「內有Ti碳化物或/及Ti碳氮化物的實質上 」之存在謀取被割性之提升，爲使該Mn S安定存 中，Ti及Ν係以滿足Ti ( % ) /Ν ( % ) 2 1 .35爲佳 由於，如上述，Ti ( %) /N ( %) 2 1.35時，所添； 幾乎已在凝固早期生成TiN，無法安定得「內有： 物或/及Ti碳氮化物的實質上之MnS」。 以如上調整之含量的各元素構成之化學組成 )式及（ii )所規定之夾雜物形態，可得具優良被 熱加工性及加工面性狀之低碳易割鋼。 本發明之低碳易割鋼，可更合選自上述第一群 群之至少一群中的一種以上之成分。 (1 ) 第一群元素 第一群元素係，上述主要組成以外無礙於本發 之效果，更提升鋼之被割性的元素。因此，爲得更 被割性，以含一種以上爲佳。The Ti system forms a Ti carbide or/and a Ti carbonitride together with N and C, and an important element which contains such MnS in the steel. As described above, if there is a "substantial MnS having Ti carbide or/and Ti carbonitride in the steel" in the steel, the tool life at the time of high-speed cutting using a superhard tool is greatly enhanced. In order for such MnS to exist, it must be contained in an amount of 0.002% or more. In order to disperse such stability in steel, the thickness of the machined surface is deteriorated, and a good tool life is obtained, and the balance of the Ti content and the content of S and N must be considered. Further, when the Ti content exceeds 0.10%, the "substantial Ti sulfide or/and Ti carbon sulfide" is present in the steel, and the thickness of the processed surface is deteriorated during the processing and cutting. Therefore, Ti is limited to 0. 10%. For a more stable surface roughness, the Ti content is preferably 8% or less. Not as good as 〇. 〇 3 % is even better. On the other hand, when the Ti content is less than 0.002%, "substantially MnS having Ti carbide or/and Ti carbonitride therein" which is sufficient to increase the life of the tool cannot be produced. In order to more effectively generate the MnS, it is preferable to improve the life of the superhard tool by more than 0.01%. P : 0.00 1 to 0.3 0% -25- (22) 1247815 P Improves the hardenability of steel while increasing strength. In order to achieve this effect, it is preferred to contain 0.001% or more. In addition, if it is 0.30% or less, there is no deterioration of the cut property, and the hardenability and strength can be ensured. When the content exceeds 〇. 30%, the strength is too high, and not only the cut property is deteriorated, which also contributes to the segregation of the steel block and the hot workability. Deterioration. Therefore, the P content is made 0.001 to 0.30%. For stability and maintain good cuttability and strength, the preferred content is 〇 〇 〇 5 to 0.1 3 %. A1: 0.2% or less (may not be added) A1 is used as a strong deoxidizing element, and may be contained in an amount of 2. 2% or less. However, the oxide formed by deoxidation is hard, and when the content exceeds 0.2%, a large amount of hard oxide is formed, and the cut property is deteriorated. Therefore, the better one is 0.1% or less. Further, when it is possible to sufficiently deoxidize by adding C and Μη, A1 may not be added, and the content may be 0.002% or less of impurities. 0 (oxygen): 0·001 to 0.03% The effect of oxygen in the steel of the present invention is not impaired with the deoxidation state, so that it contains an appropriate amount of oxygen, and is dissolved in MnS to prevent MnS from being stretched by rolling, improving the machinery. Anisotropy of nature. It is also effective in improving cut, hot workability and S segregation. However, if it exceeds 0.03%, it may cause a loss of refractory or the like due to melting. Therefore, the oxygen content is in the range of 0 · 0 0 1 to 0 · 0 3 %. For the above effects, the better range is from 0·0 0 1 5 to 0.01%. N: 0.0005 to 0.02% N is easy to form a hard nitride together with Al and Ti. These nitrides are effective in refining crystal grains. However, with the presence of a large amount of nitrides, the wear of the tool is easily accelerated, and the cut property is deteriorated. In the steel of the present invention, Ti is added as a necessary component, and the lower the N content, the better the effect is obtained, so that it contains -26-1247815 (23) 0.0 00 5 % or more. On the other hand, if the N content is excessive, coarseness is generated, and the cutiness is impaired, so the upper limit of N is 0.02%. For better cut, the upper limit of the amount of N is preferably 0 · 0 15 %. In addition, this system seeks to improve the cuttability by the existence of "substantially having Ti carbides or/and Ti carbonitrides." In order to stabilize the Mn S, Ti and lanthanides satisfy Ti (%). /Ν (%) 2 1.35 is preferred because, as mentioned above, Ti (%) / N (%) 2 1.35 is added; TiN is formed almost in the early stage of solidification, and it is impossible to settle "inside: or / And the substantial MnS of the Ti carbonitride. The low-carbon easy-cut steel having excellent hot workability and surface properties can be obtained by the chemical composition of each element having the above-mentioned adjusted content and the form of inclusion defined by the formula (ii). The low carbon cut-to-cut steel of the present invention may more preferably be selected from one or more of at least one of the above-mentioned first group. (1) The first group of elements The first group of elements, other than the above-mentioned main components, does not impede the effects of the present invention, and enhances the cuttability of steel. Therefore, in order to be more severable, it is preferable to contain one or more.
Se: 0.0005 至 0.10% > Te: 0.0005 至 0.10%Se: 0.0005 to 0.10% > Te: 0.0005 to 0.10%
Se及Te連同Μη生成Mn(S，Se)及Mn(S 。此等與MnS同，係在切割中發揮擬潤滑效果， 割性之有效元素，而爲更提升被割性以在上述範圍 。但是各含量不及〇 . 〇 〇 〇 5 %則無效。另一方面，S 丁 e其含量超過0 ·] 〇 %則不只效果飽和，且變得不經 之 TiN 硬保更 發明中 之MnS 在於鋼 。此乃 扣之Ti 「i碳化 ，及（i 割性、 至第三 明可得 優良之 ，Te ) 改善被 內爲佳 e以及 濟，熱 -L7 - (24) 1247815 加工性劣化。爲更安定兼得熱加工性及被割性，各以 0.0 0 1 0 至 0.0 5 % 爲佳。 B i : 0 · 0 1 至 0 · 3 %、S η : 0.0 1 至 0 · 3 °/〇Se and Te together with Μη generate Mn(S,Se) and Mn(S. These are the same as MnS, which are effective elements for the lubricity and cleavage in cutting, and are in the above range to improve the cuttability. However, the content is less than 〇. 〇〇〇 5% is invalid. On the other hand, the content of S e e is more than 0 ·] 〇% is not only saturated, but also becomes TiN hard. The MnS in the invention is in steel. This is the Ti of the "I carbonization, and (i cut, to the third best available Te, Te) improvement is better than the internal and the heat, L7 - (24) 1247815 processability deterioration. Stability and hot workability and cutability are preferably 0.0 0 1 0 to 0.0 5 %. B i : 0 · 0 1 to 0 · 3 %, S η : 0.0 1 to 0 · 3 ° / 〇
Bi及Sn具有改善鋼的被割性之效果。此應係由於如 同Pb，成爲低熔點夾雜物，於切割時發揮潤滑效果。爲 確保該效果，各含量宜在〇·〇1%以上。但若其含量各超過 0.3 %則不僅效果飽和，熱加工性亦劣化。爲更安定兼具優 良熱加工性及被割性，各以0.03至0.1 %爲佳。Bi and Sn have the effect of improving the cuttability of steel. This should be due to the fact that Pb is a low-melting inclusion and exhibits a lubricating effect during cutting. In order to ensure this effect, each content should be more than 1% of 〇·〇. However, if the content exceeds 0.3%, the effect is saturated and the hot workability is deteriorated. For better stability and excellent hot workability and cuttability, it is preferably 0.03 to 0.1%.
Ca ： 0.0001 至 0.01%Ca : 0.0001 to 0.01%
Ca因對於S、Ο (氧）親和力大，於鋼中形成硫化物 及氧化物。又，Ca固溶於MnS中形成（Mn，Ca ) S，固 溶於其中之Ca因係微量，無損於.MnS之效果。又，由 C a形成之氧化物係低熔點氧化物，係於本發明鋼中更提 升被割性之有效添加元素。若欲以Ca之添加切實獲致被 割性之改善效果，則C a量之下限以0.0 0 0 1 %爲佳。但因 添加Ca則良率差，爲使Ca含量增大則須添加多量之Ca ’亦不利於製造成本。因此，Ca含量係以0.01 %爲上限 。更佳之上限係0.005%。Ca has a large affinity for S and Ο (oxygen) to form sulfides and oxides in steel. Further, Ca is dissolved in MnS to form (Mn, Ca) S, and the amount of Ca dissolved in it is small, which does not impair the effect of .MnS. Further, the oxide-based low-melting oxide formed of C a is an effective additive element for improving the cuttability in the steel of the present invention. If the effect of improving the cutability is actually obtained by the addition of Ca, the lower limit of the amount of Ca is preferably 0.001%. However, since Ca is added, the yield is poor, and in order to increase the Ca content, it is not preferable to add a large amount of Ca'. Therefore, the Ca content is limited to 0.01%. A better upper limit is 0.005%.
Mg ： 0.0001 至 0.005%Mg : 0.0001 to 0.005%
Mg因於鋼中亦對於S、Ο (氧）親和力大，形成硫化 物或氧化物。含M g之硫化物、氧化物具Μ n S的結晶核之 功能，有抑制MnS的延伸之效果。於欲得如此效果時添 加即可。爲充分獲取其效果，Mg量之下限以0.000 1 %以 上爲佳。但因Mg形成之氧化物係硬質，Mg含量太高則 -28- (25) 1247815 成爲被割性劣化之原因。因此Mg以0.005 %爲上限。更爲 兼得抑制MnS之延伸的效果及優良之被割性，較佳上限 係 0·002ο/〇。 Β: 0.0002 至 0.02% Β與Ο (氧）或Ν結合，形成氧化物、氮化物，因亦 具提升被割性之效果，可於必要時添加。爲得該效果，宜 含0.00 02%以上。爲更切實得該效果，宜係0.0010%以上 。但若Β含量超過0 · 02%，則不僅其效果飽和，熱加工性 亦劣化。 稀 土元素：0.0005 至 0.02% 稀土元素係分類爲鑭系元素之元素群。以之添加時通 常係使用以此等爲主要成分之美鈽合金等。本發明中稀土 元素含量表，稀土元素中一種或二種以上元素之合計量。 稀土元素與氧形成氧化物，亦與s結合形成硫化物，提升 被割性。爲確得其效果宜含0 · 0 0 〇 5 °/。以上。但含量超過 0.0 2 %則效果飽和。又，添加稀土元素因良率低，大量含 有並不經濟。 (2 )第二群元素 第二群之元素任一皆具提升鋼的強度之作用。必要時 可含此等中之一種以上。 C u : 0 · 0 1 至 1 · 〇 %Mg also has a high affinity for S and Ο (oxygen) in steel to form sulfides or oxides. The function of the nucleus containing Mn sulfide and oxide having Μ n S has the effect of suppressing the extension of MnS. Add it when you want this effect. In order to sufficiently obtain the effect, the lower limit of the Mg amount is preferably 0.000 1% or more. However, since the oxide formed by Mg is hard and the Mg content is too high, -28-(25) 1247815 is a cause of deterioration of the cut property. Therefore, Mg is limited to 0.005%. Further, it has an effect of suppressing the elongation of MnS and excellent cuttability, and the upper limit is preferably 0·002ο/〇. Β: 0.0002 to 0.02% Β combines with Ο (oxygen) or yttrium to form oxides and nitrides. It also has the effect of improving the cutability and can be added when necessary. In order to achieve this effect, it is preferable to contain 0.00 02% or more. In order to achieve this effect more effectively, it should be 0.0010% or more. However, if the cerium content exceeds 0.02%, not only the effect is saturated, but also the hot workability is deteriorated. Rare earth elements: 0.0005 to 0.02% Rare earth elements are classified as elemental groups of actinides. When it is added, it is usual to use a bismuth alloy or the like which has such a main component. In the present invention, the rare earth element content table, the total amount of one or more of the rare earth elements. The rare earth element forms an oxide with oxygen and also combines with s to form a sulfide to enhance the cut. In order to confirm its effect, it should contain 0 · 0 0 〇 5 ° /. the above. However, if the content exceeds 0.0 2%, the effect is saturated. Moreover, the addition of rare earth elements is low in yield, and it is not economical to contain a large amount. (2) The second group element Any element of the second group has the effect of increasing the strength of the steel. If necessary, one or more of these may be included. C u : 0 · 0 1 to 1 · 〇 %
Cu因析出強化而具提升鋼之強度的效果。爲得該效 果其含量須在〇·〇1 %以上。爲更切實得該效果，宜以％ 以上添加。但若含量超過1 . 0 °/。則致使熱加工性劣化，不 -29- (26) 1247815 僅因C u析出物之粗大化而上述效果飽和，亦導致被割性 變差。Cu has the effect of increasing the strength of steel due to precipitation strengthening. In order to achieve this effect, the content must be above 〇·〇1%. In order to achieve this effect more effectively, it is preferable to add it by more than %. However, if the content exceeds 1.0 ° /. As a result, the hot workability is deteriorated, and -29-(26) 1247815 is only caused by the coarsening of the Cu precipitate, and the above effect is saturated, and the cut property is also deteriorated.
Ni : 0.01 至 2.0°/〇Ni : 0.01 to 2.0 ° / 〇
Ni具有經固熔強化而提升鋼之強度的效果。爲確保 該效果，其含量以在0.01 %以上爲佳。但若超過2.0%則導 致被割性之劣化，同時熱加工性亦劣化。Ni has the effect of strengthening the strength of steel by solid solution strengthening. In order to secure this effect, the content is preferably 0.01% or more. However, if it exceeds 2.0%, the cut property is deteriorated, and the hot workability is also deteriorated.
Mo : 0.0 1 至 0.5〇/〇 Μ 〇係可提高淬火性之元素，爲提升滲碳特性，以可 得與S i、C r之添加同等效果的相當量之Μ 〇添加，則因 此Si、Cr昂貴，有架高製造成本之困難。但Mo有使組 織微細化，改善靭性之效果。於欲得此等效果時添加即可 。爲確保其效果，含量宜在0.01 %以上。但若超過0.5%則 不只效果飽和，鋼之製造成本亦上升。 V: 0.005 至 0.5% V以微細之氮化物、碳氮化物析出，提升鋼之強度。 含0.005 %以上即可得該效果，爲更確保效果，以含0.01% 以上爲佳。但若超過0 · 5 %，不僅上述效果飽和，因氮化 物、碳化物之過剩生成，導致被割性變差。Mo : 0.0 1 to 0.5 〇 / 〇Μ The element which can improve the hardenability is added. In order to improve the carburizing property, a considerable amount of Μ 〇 can be added with the same effect as the addition of S i and C r , so Si, Cr is expensive and has a high manufacturing cost. However, Mo has the effect of making the structure finer and improving the toughness. Add it when you want to get these effects. In order to ensure its effect, the content should be above 0.01%. However, if it exceeds 0.5%, not only the effect is saturated, but the manufacturing cost of steel also rises. V: 0.005 to 0.5% V is precipitated by fine nitrides and carbonitrides to increase the strength of the steel. When the content is 0.005% or more, the effect is obtained, and in order to ensure the effect, it is preferably 0.01% or more. However, if it exceeds 0.5%, not only the above effect is saturated, but also the excessive formation of nitrides and carbides causes the cuttability to deteriorate.
Nb : 0.005 至 0.5%Nb : 0.005 to 0.5%
Nb以微細之氮化物、碳氮化物析出，提升鋼之強度 。含0 · 0 0 5 %以上即可得該效果，爲更確保效果則以含 0 · 0 1 °/。以上爲佳。但若超過0 · 5 %則不僅上述效果飽和，因 氮化物、碳化物過剩生成，不只致使被割性變差，亦不經 濟。 -30- (27) 1247815 (3 )第三群元素 第三群元素係，欲提高鋼之滲碳特性時，可使其一或 二者於下述範圍內含有之元素。Nb precipitates with fine nitrides and carbonitrides to increase the strength of the steel. This effect can be obtained with 0 · 0 0 5 % or more, and 0 + 0 1 °/ for more ensuring the effect. The above is better. However, if it exceeds 0.5%, not only the above effect is saturated, but also the excessive formation of nitrides and carbides causes not only poor cuttability but also economy. -30- (27) 1247815 (3) The third group element The third group element system, in order to improve the carburizing characteristics of steel, can make one or both of the elements contained in the following range.
Si : 0·1 至 2.0% 申請專利範圍第1至4項有關之發明的易割鋼，並無 Si之積極添加。因此，Si乃雜質之一，其含量不及ο.!% 。而爲使申請專利範圍第1至4項有關之發明的鋼中氧量 適當，有時係作爲去氧元素添加，此時亦不必積極餘留， 殘留在鋼中之S i係雜質，不及〇 . 1 %。 又，Si具有固溶於肥粒鐵提升鋼之強度，同時提高 鋼之淬火性的效果。隨鋼之淬火性的提高，可得作爲汽車 零件所需之滲碳特性的提升。唯於此時Si宜含0.1 %以上 。爲更切實提升滲碳特性時，含量宜超過0.6%。但若超 過2.0%則熱加工性劣化，因肥粒鐵相之固溶強化，切割 阻力變大等，於被割性有不良影響。而係不及0.1 %之雜 質程度時，亦可經C、Μη、A1之適當添加，使鋼中氧量 在恰當之範圍內。 C r : 0 · 0 3 至 1 · 0 %Si: 0·1 to 2.0% The easy-cut steel of the invention relating to claims 1 to 4 is not actively added by Si. Therefore, Si is one of the impurities, and its content is less than ο.!%. In order to make the amount of oxygen in the steel of the invention related to the first to fourth patent applications appropriate, it is sometimes added as a deoxidizing element, and it is not necessary to actively retain it at this time, and the S i-based impurities remaining in the steel are inferior to those of the invention. . 1 %. Further, Si has the effect of solid-solubilizing iron to increase the strength of the steel and improve the hardenability of the steel. With the improvement of the hardenability of steel, it can be improved as a carburizing characteristic required for automobile parts. Only at this time, Si should contain 0.1% or more. In order to improve the carburizing characteristics more effectively, the content should exceed 0.6%. However, if it exceeds 2.0%, the hot workability is deteriorated, and the solid solution strengthening of the iron phase of the fat grain and the cutting resistance become large, which adversely affects the cut property. When the degree is less than 0.1%, the appropriate amount of C, Μη, and A1 may be added to make the oxygen content in the steel within an appropriate range. C r : 0 · 0 3 to 1 · 0 %
Cr係爲提升鋼之淬火性，以少量添加即可提升滲碳 特性之元素。含Cr之鋼滲碳特性改善，滲碳處理後滲碳 層硬度高，可提高有效硬化深度。爲得該效果，宜含 CrO· 03 %以上。又，欲更切實提升滲碳特性時，含量宜超 過0.05%。但若Cr含量超過1.0%則不只被割性劣化，製 -31 - 1247815 (28) 造成本亦架高。 含上述之Si或/及Cr，即可得具優良被割性、熱加工 性、以及優良滲碳特性之鋼。 實施例 1.試樣之製作 使用高頻加熱感應爐製作具表1及表2之種種組成的 1 5 0kg鋼炔（直徑約220mm )。表1示本發明鋼，表2示 習知鋼或比較鋼。爲使此等鑄片安定生成「內有Ti碳化 物或/及Ti碳氮化物的實質上之MnS」，加熱至125(TC之 高溫後，保持2小時，接著模擬輥軋過程於1 000 °C以上 進行加工鍛造，經氣冷得直徑65mm之圓棒。然後加熱該 鍛伸材至95 0 °C，保持1小時後，氣冷進行正常化處理。 而比較例之鋼No. 51至53熱加工性惡劣，鍛造之際產生 裂痕無法製成鍛伸材，未實施以下之檢測。 -32- 1247815 (29) -33- 1247815 (30) -34 - (31) 1247815 2 .夾雜物形態之檢測 平行於輥軋方向之剖面所觀察到之夾雜物，多係 工方向延伸或形狀不特定者。檢測夾雜物之個數、面 ’自鍛伸材的Df/4 ( Df :鍛伸材直徑）部之縱剖面方 切出顯微觀察用試片，包埋於樹脂後，進行鏡面硏磨， 4〇〇倍之光學顯微鏡觀察進行照明，經圖像解析等手法 出夾雜物之個數及面積。此際，以換算爲具相同面積之 時的直徑，圓相當直徑以1 μ m以上者爲對象。圓相當 徑之限定於1 // m以上乃因，如前敘，不及1 // m之夾 物於被割性幾不具效果。 ： 又，此等夾雜物之組成係如下確認。亦即，如上述 鍛伸材之Df/4 ( Df :鍛伸材直徑）部的縱剖面方向切 之顯微試片，包埋於樹脂後，進行鏡面硏磨以ΕΡΜΑ ( 子束微分析儀）、EDX (能散X射線析析裝置）等進行 分析及定量分析。此時之觀察倍率宜選在不超出10000 :之範圍，以該觀察倍率可觀察到一個夾雜物中MnS與 碳化物或/及Ti碳氮化物明確相分離，且確認MnS之面 率在50%以上的夾雜物即係「內有Ti碳化物或/及Ti 氮化物的實質上之MnS」。由如此觀察之結果，求出圓 當直徑1 // m以上之各「內有Ti碳化物或/及Ti碳氮化 的實質上之MnS」及「內無Ti碳化物、Ti碳氮化物的 質上之MnS」的面積，並算出輥軋方向剖面1 mni2中此 夾雜物之合計面積，更算出輥軋方向剖面1 mm2中全部 雜物所占面積之合計，求出（A + B ) /C。 加 時 向 以 求 圓 直 雜 白 取 電 面 倍 Ti 積 碳 相 物 實 等 夾 -35- (32) 1247815 由上述結果測定「內有Ti碳化物或/及Ti碳氮化物 的實質上之MnS」的個數，以輥軋方向剖面每lmm2平均 個數有5以上之鋼爲「0」。反之，「內有Ti碳化物或/ 及Ti碳氮化物的實質上之MnS」不及5個之鋼則爲「X 」。而表2之比較例的鋼No.35至37係不含Ti之Pb易 割鋼、S易割鋼，因實質上無「內有Ti碳化物或/及Ti碳 氮化物的實質上之MnS」存在，未進行此等計算。 3 .被割性試驗 被割性試驗係使用將上述鍛伸材車削至直徑60mm之 圓棒，進行工具壽命及加工面粗度檢測之試驗。工具壽命 試驗係使用未經被覆處理之JIS規定的P20類超硬工具， 以切割速度 ：150m/min，走刀：0.10mm/rev，切深： 2 . Omm之乾式條件進行車肖U，測定自切割開始3 0分鐘後 之平均隙面磨損量。而對於3 0分鐘以內之平均隙面磨損 量達200 // m以上之供試材，則測定其到達時間及此時之 平均隙面磨損量（VB )。 評估係以平均隙面磨損量（VB )達1 00 μ m之時間爲 工具壽命之標準而進行。而，對於試驗當中耐磨損性優， 磨損進行速度極小而供試材不足者，係由車削時間-工具 磨損曲線回歸出平均隙面磨損量達1 〇〇 β πι之時間而算出 。又，切屑處理性係採取此時排出之切屑中具代表性的 2 00個，測定其重量，算出每單位重量之個數作評估。 加工面粗度因係以加工切割後之表面粗度作評估，係 -36- (33) 1247815 用觸針粗度計評估經以下條件切割後之被割材料表面。切 割條件係使用施以多層TiAIN被覆之ns K類超硬工具， 以切割速度：l〇〇m/min，走刀：0.05mm/rev，切深： 0.5mm之使用水溶性乳劑型潤滑油的濕式條件之車肖!J。對 於供試鋼以該條件切割1分鐘後之試片，用觸針粗度計於 軸向移動觸針測定平均加工面精度（Ra )，評估加工面之 粗度。 4.熱加工性試驗 熱加工性係爲模擬連續鑄造設備下之製造條件，以用 同上手法製作之150kg鋼块表面部近於Di/8 ( Di :鋼块直 徑）之位置爲中心，由鋼块高度方向製成直徑1 Omm，長 度1 3 0 m m之高溫拉伸試片，以於固定間隔1 1 〇 m m直接通 電加熱至1 25 0 °C，保持5分鐘後，以l〇°C/sec之冷卻速 度冷卻至1100°C保持10秒後以應變速率10_3/s進行拉伸 試驗。此時，測定斷裂部之收縮率評估熱加工性。 5 ·滲碳試驗 滲碳試驗係如下實施。亦即，試片係用直徑24mm、 長度50mm之圓柱狀鋼材。此係採取自前敘直徑65mm之 正常化材料的R/2位置。該試片於900 °C加熱作滲碳處理 ，然後於8 5 0 °C作擴散處理。此時，滲碳時之碳位能（ C . P ·)値係〇 · 8 %，處理時間7 5分鐘，擴散時之C · P ·値 0 · 7 %，處理時間2 0分鐘。滲碳處理結束之試片於8 0 °C之 (34) 1247815 油中冷卻施以淬火處理。最後將試片加熱至1 9 0 °C，保持 於該溫度60分鐘施以回火處理。滲碳性之評估方法如下 〇 距經滲碳淬火·回火處理之試片端25mm之位置（亦 即長度方向之中央）的橫剖面，測定自表面往內部的維克 氏硬度分布，求出Hv400之有效硬化深度，判斷該値係 比習知鉛複合易割鋼大或小。習知鉛複易割鋼係表2之鋼 No.35，其有效硬化深度係0.25mm。滲碳性之評估係，有 效硬化深度相對於鋼 No.35 土 0.05mm者，亦即，0.20至 0.30mm 者判定爲同等，不及 0.20mm者爲劣，超過 0.3 0mm者爲優。其結果於表3及表4以〇、X及◎示之 。同等者爲「〇」，劣.者爲「X」，，優者爲「◎」。 以上試驗結果整理列示於表3及表4。又’第2圖示 (i )式之（A + B ) /C與加工表面粗度之關係，第3圖示 加工面粗度與工具壽命之關係，第4圖示切屑處理性與工 具壽命之關係。 1247815 (35) 【表3】 鋼No 收縮率 (%) 30分鐘後 工具磨損量 (ϋ m) 抵達VB=100 //m之時間 C分） 切屑處理性 (個數/g) 加工表面 平均粗度 (u m) 滲碳性 評估 61.8 45 90 18 0.7 〇 2 64.3 39 98 14 0.6 〇 3 64.5 48 85 12 0.2 〇 L. 80.2 32 125 18 0.5 〇 5 76.8 43 96 21 0.3 〇 6 63. 6 44 91 14 0.7 〇 7 67.2 38 96 16 0· 7 〇 8 65. 2 42 98 17 0.3 〇 9 81.4 36 121 20 0.4 〇 10 76. 8 45 93 19 0.4 〇 11 73.4 40 103 16 0.4 〇 12 71.8 42 100 14 0.5 ◎ 13 64. 7 45 93 18 0.2 ◎ 14 82.9 46 90 18 0.2 ◎ 15 65.2 42 98 17 0.4 ◎ 16 72.8 44 95 18 0.4 ◎ 17 80. 1 42 95 12 0.4 ◎ 18 71.0 38 110 18 0.3 〇 19 69. 5 40 98 19 0.3 〇 20 62. 9 45 92 24 0. 3 〇 21 64. 8 46 93 13 0.2 〇 22 60. 8 29 120 19 0.5 〇 23 62. 8 43 95 22 0. 6 〇 24 81.2 38 105 16 0.5 〇 25 75.9 41 101 20 0.4 〇 26 78. 7 43 97 16 0· 3 〇 27 75.4 40 105 22 0.3 〇 28 80.5 42 93 14 0.8 〇 29 78.8 36 115 18 0.3 〇 30 64.2 37 105 24 0.4 〇 31 60.9 46 91 20 0· 3 〇 32 61.3 44 90 18 0· 3 〇 33 64.3 24 126 19 0.5 〇 34 67.2 41 99 17 0. 3 〇 -39- 1247815 (36) 【表4】 鋼No 收縮率 (%) 30分鐘後 工具磨損量 Cum) 抵達VB=100 //m之時間 ⑼ 切屑處理性 (個數/g) 加工表面 平均粗度 (u m) 滲碳性 評估 35 49. 8 98 36 9 ' 0.4 〇 36 49. 6 99 30 8 0·7 〇 37 55,4 165 17 6 0.7 〇 38 74. 3 35 113 15 1.3 X 39 73.0 40 98 17 1.4 X 40 68.2 45 92 18 1.5 X 41 64.2 71 68 16 1.7 X 42 67.5 89 38 15 0.5 〇 43 79.0 85 42 13 0.6 ◎ 44 52.8 93 36 12 1.3 ◎ 45 66.9 88 39 15 1.0 ◎ 46 57.5 103 29 8 1.6 X 47 78.7 101 30 16 0.3 〇 48 56.0 232 12 12 1.8 ◎ 49 59.8 206 16 14 1.9 ◎ 50 65.3 129 20 9 1. 3 〇 51 6.4 — 一 一 一 一 52 4. 3 一 一 — 一 一 53 3.4 一 一 — 一 一 54 59. 5 198 17 15 1. 8 〇 55 58. 5 264 10 10 1.9 ◎ - 40 - (37) 1247815 表2之鋼Ν ο · 3 5及3 6係複合易割鋼，鋼n 〇 · 3 7係硫 易割鋼，係目前爲止被割性可爲最優之鋼。由表3、表4 、第2圖及第3圖知’本發明鋼工具壽命與加工面粗細倶 優。並且本發明鋼Ν 〇. 1至3 4熱加工性優，以連續鑄造設 備等模擬實用製造之高溫接伸試驗的收縮率如表3，與複 合易割鋼、硫易割鋼同等以上，無任何問題。 爲提升表1之鋼Ν ο · 1 2至1 7的滲碳性，係使s i及C r 之至少一種於規定範圍內含有。此等鋼係本發明鋼中呈示 特優之滲碳特性者。另一方面，如鋼No· 35至55，脫離 本發明中規定之夾雜物狀態、化學組成等之一者，工具壽 命、加工面粗細、切屑處理性、熱加工性中之至少其一較The Cr system is an element that enhances the hardenability of steel and increases the carburization characteristics by adding a small amount. The carburization characteristics of the steel containing Cr are improved, and the hardness of the carburized layer after carburizing is high, which can improve the effective hardening depth. In order to obtain this effect, it is preferable to contain CrO·03% or more. Also, in order to more effectively improve the carburizing characteristics, the content should preferably exceed 0.05%. However, if the Cr content exceeds 1.0%, it will not only be degraded by the cutability, but also the -31 - 1247815 (28). A steel having excellent cuttability, hot workability, and excellent carburization characteristics can be obtained by containing the above Si or/and Cr. EXAMPLES 1. Preparation of Samples 150 kg of steel alkyne (about 220 mm in diameter) having various compositions of Tables 1 and 2 was produced using a high-frequency heating induction furnace. Table 1 shows the steel of the present invention, and Table 2 shows a conventional steel or a comparative steel. In order to stabilize these slabs to form "substantial MnS with Ti carbide or/and Ti carbonitride", heat to 125 (after TC high temperature, hold for 2 hours, then simulate rolling process at 1 000 °) C is processed and forged, and air-cooled to obtain a round rod with a diameter of 65 mm. Then the forged material is heated to 95 ° C for 1 hour, and then air-cooled for normalization. The steel No. 51 to 53 of the comparative example. The hot workability is poor, and the crack is not formed into a forged material at the time of forging, and the following test is not carried out. -32- 1247815 (29) -33- 1247815 (30) -34 - (31) 1247815 2. Inclusion form The inclusions observed in the cross section parallel to the rolling direction are detected, and the multi-work direction is extended or the shape is not specific. The number of inclusions and the surface 'Df/4 of the self-forged material (Df: forged material diameter) The longitudinal section of the section is cut out for the microscopic observation test piece, embedded in the resin, mirror-honed, 4 times the optical microscope for illumination, image analysis and other methods to extract the number of inclusions Area. In this case, the diameter is equivalent to 1 mm when converted to the same area. The upper one is the object. The circle is limited to 1 // m or more. As mentioned above, less than 1 // m is not effective in the cut. However, the composition of these inclusions is as follows: Confirmation, that is, a microscopic test piece cut in the longitudinal section direction of the Df/4 (Df: forged material diameter) portion of the above-mentioned forged material, after being embedded in the resin, mirror honing is performed to ΕΡΜΑ (subbeam micro Analytical and quantitative analysis of the analyzer, EDX (energy dispersive X-ray analyzer), etc. At this time, the observation magnification should be selected within a range not exceeding 10000:, and MnS and carbonization in one inclusion can be observed at the observation magnification. The inclusions of the material or/and the Ti carbonitride are clearly phase-separated, and the inclusions having a surface ratio of MnS of 50% or more are confirmed to be "substantially MnS having Ti carbides or/and Ti nitrides". As a result, each of the "MnS with a Ti carbide or/and Ti carbonitride" and a MnS having no Ti carbide or Ti carbonitride in the circle having a diameter of 1 // m or more were obtained. Area, and calculate the total area of the inclusions in the rolling direction section 1 mni2, and calculate the rolling direction section 1 mm2 For the total area of all the debris, find (A + B ) /C. Add the time to find the straight surface, and take the electric surface to double the carbon phase. -35- (32) 1247815 The number of "substantially MnS having Ti carbide or/and Ti carbonitride in the inside" is measured, and the steel having 5 or more averages per 1 mm 2 in the rolling direction section is "0". The substantially MnS of the carbide or/and Ti carbonitride is less than 5 steels and is "X". The steel No. 35 to 37 of the comparative example of Table 2 is a Pb free-cutting steel or a S-cut steel which does not contain Ti, because there is substantially no substantial MnS having Ti carbide or/and Ti carbonitride therein. There is no such calculation. 3. Cutability test The cut test was carried out by turning the above-mentioned forged material into a round bar of 60 mm in diameter to test the tool life and the roughness of the machined surface. The tool life test is a P20 type superhard tool specified by JIS without coating, with cutting speed: 150m/min, pass: 0.10mm/rev, depth of cut: 2. Omm dry condition for car U, determination The average amount of gap wear after 30 minutes from the start of cutting. For the test material with an average gap wear of more than 200 // m within 30 minutes, the arrival time and the average gap wear (VB) at this time were measured. The evaluation was carried out with a mean gap wear (VB) of 100 μm as the standard for tool life. However, for the test, the wear resistance is excellent, the wear speed is extremely small, and the test material is insufficient, which is calculated by the time when the turning time-tool wear curve returns the average gap wear amount to 1 〇〇 β πι. Further, the chip-treating property was taken from the representative of the chips discharged at this time, and the weight was measured, and the number per unit weight was calculated for evaluation. The roughness of the machined surface was evaluated by the surface roughness after machining and cutting. -36- (33) 1247815 The surface of the cut material after cutting was evaluated using a stylus roughness meter. The cutting conditions are ns K-type superhard tools coated with multiple layers of TiAIN, with cutting speed: l〇〇m/min, pass: 0.05 mm/rev, depth of cut: 0.5 mm using water-soluble emulsion type lubricants Wet condition car Xiao! J. For the test piece after the test steel was cut for 1 minute under the conditions, the average work surface accuracy (Ra) was measured by the stylus thickness gauge in the axial movement stylus, and the roughness of the machined surface was evaluated. 4. Hot workability test The hot workability is a manufacturing condition under the condition of simulating continuous casting equipment, and the surface of the 150 kg steel block which is made by the same method is near the position of Di/8 (Di: steel block diameter), and is made of steel. A high-temperature tensile test piece with a diameter of 1 Omm and a length of 130 mm is made in the height direction of the block, and is directly heated to 1.25 ° C at a fixed interval of 1 1 〇mm, and after 5 minutes, at 10 ° C / The cooling rate of sec was cooled to 1100 ° C for 10 seconds and then subjected to a tensile test at a strain rate of 10_3 / s. At this time, the shrinkage rate of the fracture portion was measured to evaluate the hot workability. 5 · Carburizing test The carburizing test was carried out as follows. That is, the test piece is a cylindrical steel material having a diameter of 24 mm and a length of 50 mm. This is taken from the R/2 position of a normalized material with a diameter of 65 mm. The test piece was heated at 900 °C for carburization and then subjected to diffusion treatment at 850 °C. At this time, the carbon energy at the time of carburization (C.P.) is 88 %, the treatment time is 75 minutes, the diffusion time is C · P · 値 0 · 7 %, and the treatment time is 20 minutes. The test piece after the carburization treatment was cooled at 80 °C (34) 1247815 oil and quenched. Finally, the test piece was heated to 190 ° C and maintained at this temperature for 60 minutes for tempering. The evaluation method of carburization is as follows: the transverse section of the position of the carburized quenching and tempering test piece 25 mm (that is, the center of the longitudinal direction) is measured, and the Vickers hardness distribution from the surface to the inside is measured to obtain Hv400. The effective hardening depth is judged to be larger or smaller than the conventional lead composite easy-cut steel. The conventional lead-reversible and easy-cut steel is No.35 of Table 2, and its effective hardening depth is 0.25 mm. For the evaluation of carburization, the effective hardening depth is 0.05 mm with respect to steel No. 35 soil, that is, 0.20 to 0.30 mm, which is judged to be equal, less than 0.20 mm, and more than 0.30 mm. The results are shown in Tables 3 and 4 as 〇, X and ◎. The equivalent is "〇", the inferior is "X", and the superior is "◎". The above test results are summarized in Tables 3 and 4. Further, the relationship between (A + B ) /C of the second graph (i) and the surface roughness of the machined surface, the third graph shows the relationship between the roughness of the machined surface and the tool life, and the fourth graph shows the chip handling property and the tool life. Relationship. 1247815 (35) [Table 3] Steel No shrinkage (%) Tool wear after 30 minutes (ϋ m) Time to reach VB=100 //m C minutes) Chip handling (number/g) Average surface roughness Degree (um) Carburization evaluation 61.8 45 90 18 0.7 〇2 64.3 39 98 14 0.6 〇3 64.5 48 85 12 0.2 〇L. 80.2 32 125 18 0.5 〇5 76.8 43 96 21 0.3 〇6 63. 6 44 91 14 0.7 〇7 67.2 38 96 16 0· 7 〇8 65. 2 42 98 17 0.3 〇9 81.4 36 121 20 0.4 〇10 76. 8 45 93 19 0.4 〇11 73.4 40 103 16 0.4 〇12 71.8 42 100 14 0.5 ◎ 13 64. 7 45 93 18 0.2 ◎ 14 82.9 46 90 18 0.2 ◎ 15 65.2 42 98 17 0.4 ◎ 16 72.8 44 95 18 0.4 ◎ 17 80. 1 42 95 12 0.4 ◎ 18 71.0 38 110 18 0.3 〇 19 69. 5 40 98 19 0.3 〇20 62. 9 45 92 24 0. 3 〇21 64. 8 46 93 13 0.2 〇22 60. 8 29 120 19 0.5 〇23 62. 8 43 95 22 0. 6 〇24 81.2 38 105 16 0.5 〇25 75.9 41 101 20 0.4 〇26 78. 7 43 97 16 0· 3 〇27 75.4 40 105 22 0.3 〇28 80.5 42 93 14 0.8 〇29 78.8 36 115 18 0.3 〇30 64.2 37 105 24 0.4 〇31 60.9 46 91 20 0· 3 〇32 61.3 44 90 18 0· 3 〇33 64.3 24 126 19 0.5 〇34 67.2 41 99 17 0. 3 〇-39- 1247815 (36) [Table 4] Steel No shrinkage (%) 30 Minutes of tool wear Cum) Time to reach VB=100 //m (9) Chip handling (number/g) Average surface roughness (um) Carburization evaluation 35 49. 8 98 36 9 ' 0.4 〇36 49 6 99 30 8 0·7 〇37 55,4 165 17 6 0.7 〇38 74. 3 35 113 15 1.3 X 39 73.0 40 98 17 1.4 X 40 68.2 45 92 18 1.5 X 41 64.2 71 68 16 1.7 X 42 67.5 89 38 15 0.5 〇43 79.0 85 42 13 0.6 ◎ 44 52.8 93 36 12 1.3 ◎ 45 66.9 88 39 15 1.0 ◎ 46 57.5 103 29 8 1.6 X 47 78.7 101 30 16 0.3 〇48 56.0 232 12 12 1.8 ◎ 49 59.8 206 16 14 1.9 ◎ 50 65.3 129 20 9 1. 3 〇 51 6.4 — 111-152 4. 3 One-one-one 53 3.4 One-one-one 54 59. 5 198 17 15 1. 8 〇55 58. 5 264 10 10 1.9 ◎ - 40 - (37) 1247815 Table 2 steel Ν ο · 3 5 and 3 6 series composite easy-cut steel, steel n 〇 · 3 7 series sulfur easy-cut steel, is currently cut off For the best steel. From Tables 3, 4, 2, and 3, the life of the steel tool of the present invention and the thickness of the machined surface are excellent. Further, the steel Ν 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 连续 连续 连续 连续 连续 连续 连续 连续 连续 连续 连续 连续any problem. In order to improve the carburization property of the steel Ν ο 1 2 to 17 of Table 1, at least one of s i and C r is contained within a predetermined range. These steels are those exhibiting superior carburizing characteristics in the steel of the present invention. On the other hand, if steel No. 35 to 55 deviate from one of the inclusion state and chemical composition specified in the present invention, at least one of tool life, machined surface thickness, chip handling property, and hot workability is compared.
I 本發明鋼差' 以上由實施例具體說明本發明，但本發明並不限定於 此等實施例，未揭示之實施例如果能滿足本發明要件當然 包含於本發明。 產業上之利用可能性 本發明之易割鋼，不僅不含Pb，並具有與習知Pb易 割鋼及複合易割鋼同等以上之被割性，而且切割後加工面 性狀亦優。又，含Si或/及Ci*者滲碳特性優。又再，該 鋼熱加工性亦優，可經連續鑄造法廉價製造。因不含Pb 故無環境污染之虞。因此，本發明之易割鋼係作爲各種機 械零件之材料的極其合適之鋼材。 (38) 1247815 【圖式簡單說明】 第1圖 本發明鋼及比較鋼之夾雜物形態的示意圖 〇 第2圖 本發明鋼及比較鋼之（A + B ) /C與平均加 工面粗度之關係圖。 第3圖 本發明鋼及比較鋼之平均加工面粗度與工 具壽命之關係圖。 第4圖 本發明鋼及比較鋼之切屑處理性與工具壽 命之關係圖。 -42-I. The present invention is specifically described by the examples, but the present invention is not limited to the embodiments, and the unexpressed embodiments are of course included in the present invention if they satisfy the requirements of the present invention. INDUSTRIAL APPLICABILITY The easy-cut steel of the present invention not only does not contain Pb, but also has the same cuttability as conventional Pb easy-cut steel and composite easy-cut steel, and has excellent surface properties after cutting. Further, those containing Si or/and Ci* are excellent in carburization characteristics. Further, the steel is excellent in hot workability and can be inexpensively produced by a continuous casting method. Because there is no Pb, there is no environmental pollution. Therefore, the easy-cut steel of the present invention is an extremely suitable steel material as a material of various mechanical parts. (38) 1247815 [Simplified illustration of the drawings] Fig. 1 is a schematic view showing the form of inclusions of the steel of the present invention and comparative steel. Fig. 2 (A + B ) / C of the steel of the present invention and the comparative steel and the average thickness of the machined surface relation chart. Fig. 3 is a graph showing the relationship between the average surface roughness of the steel of the present invention and the comparative steel and the tool life. Fig. 4 is a graph showing the relationship between chip handling property and tool life of the steel of the present invention and comparative steel. -42-
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| JP2003285463A JP3918787B2 (en) | 2003-08-01 | 2003-08-01 | Low carbon free cutting steel |
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| EP (1) | EP1507016B1 (en) |
| JP (1) | JP3918787B2 (en) |
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| JP5241734B2 (en) * | 2006-12-28 | 2013-07-17 | ポスコ | Environmentally friendly lead-free free-cutting steel with excellent machinability and hot-rollability |
| KR100825566B1 (en) * | 2006-12-28 | 2008-04-25 | 주식회사 포스코 | Eco-friendly pb-free free cutting steel with excellent machinability and hot workability |
| KR100979058B1 (en) * | 2007-10-17 | 2010-08-30 | 주식회사 포스코 | Eco-friendly pb-free free cutting steel with excellent machinability and hot workability |
| JP4473928B2 (en) * | 2007-04-18 | 2010-06-02 | 新日本製鐵株式会社 | Hot-worked steel with excellent machinability and impact value |
| KR101018091B1 (en) | 2008-07-09 | 2011-02-25 | 주식회사 포스코 | Lead-free free cutting steel with excellent surface roughness through low built-up edge and manufacturing method thereof |
| KR101027246B1 (en) | 2008-08-06 | 2011-04-06 | 주식회사 포스코 | Free-Cutting Steel with Excellent Machinability and Manufacturing Method Thereof |
| TWI391500B (en) * | 2008-08-06 | 2013-04-01 | Posco | Eco-friendly pb-free free-cutting steel and manufacturing method thereof |
| KR101105084B1 (en) * | 2008-11-04 | 2012-01-16 | 주식회사 포스코 | Eco-friendly pb-free free-cutting steel with excellent machinability |
| JPWO2010134583A1 (en) * | 2009-05-22 | 2012-11-12 | 新日本製鐵株式会社 | Machine structural steel with excellent cutting tool life and cutting method thereof |
| KR101289103B1 (en) | 2009-12-14 | 2013-07-23 | 주식회사 포스코 | Pb-Free Free-Cutting Steel Wire Rod With Excellent Machinability And Hot Workability And Manufacturing Method The Same |
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| CN104911457A (en) * | 2014-03-15 | 2015-09-16 | 紫旭盛业（昆山）金属科技有限公司 | High temperature-resistance die steel |
| CN103911550A (en) * | 2014-03-24 | 2014-07-09 | 北京科技大学 | Environment-friendly low-carbon high-sulfur and bismuth free-cutting steel with excellent thermoplasticity |
| CN104696379B (en) * | 2015-02-10 | 2017-12-19 | 山东金马工业集团股份有限公司 | Section fork product and preparation method thereof |
| US10400320B2 (en) | 2015-05-15 | 2019-09-03 | Nucor Corporation | Lead free steel and method of manufacturing |
| JP6468365B2 (en) | 2015-11-27 | 2019-02-13 | 新日鐵住金株式会社 | Steel, carburized steel parts, and method of manufacturing carburized steel parts |
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| CN110129516A (en) * | 2019-06-11 | 2019-08-16 | 南京钢铁股份有限公司 | A kind of method of oxide morphology in control low carbon high sulfur free-cutting steel |
| CN110714161B (en) * | 2019-10-17 | 2020-09-22 | 中天钢铁集团有限公司 | High-sulfur free-cutting steel for automobile and production process thereof |
| CN110791709B (en) * | 2019-11-11 | 2020-12-04 | 广东韶钢松山股份有限公司 | Structural steel wire rod and method for improving cutting performance of structural steel wire rod |
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| JP2005054227A (en) | 2005-03-03 |
| CN1306056C (en) | 2007-03-21 |
| TW200506071A (en) | 2005-02-16 |
| KR100615465B1 (en) | 2006-08-25 |
| DE602004007730D1 (en) | 2007-09-06 |
| JP3918787B2 (en) | 2007-05-23 |
| CN1580312A (en) | 2005-02-16 |
| EP1507016B1 (en) | 2007-07-25 |
| DE602004007730T2 (en) | 2008-04-30 |
| US20050025658A1 (en) | 2005-02-03 |
| EP1507016A1 (en) | 2005-02-16 |
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