TWI307720B - - Google Patents

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TWI307720B
TWI307720B TW95119013A TW95119013A TWI307720B TW I307720 B TWI307720 B TW I307720B TW 95119013 A TW95119013 A TW 95119013A TW 95119013 A TW95119013 A TW 95119013A TW I307720 B TWI307720 B TW I307720B
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Taiwan
Prior art keywords
steel
less
content
machinability
cutting
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TW95119013A
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Chinese (zh)
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TW200704780A (en
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Naoki Matsui
Takayuki Nishi
Toru Kato
Tatsuya Hasegawa
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Sumitomo Metal Ind
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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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C22C38/60—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)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Steel (AREA)

Description

1307720 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於低碳含硫快削鋼’更詳細地說’係關於 :即使不含Pb的情況下，亦具有與以往的含鉛快削鋼（以 下，稱「含Pb快削鋼」）以及複合添加了 Pb與S、P之類 的其他快削元素之複合快削鋼（以下，稱「含pb複合快削 鋼」）同等或更良好的被切削性之低碳含硫快削鋼。更具 體地說，係關於：在使用高速鋼工具來進行切削時’具有 良好的被切削性，並且具有優異的滲碳性’而且因爲具有 優異的連續鑄造性，所以可低價地大量生座之不含Pb的 低碳含硫快削鋼。 【先前技術】 以往之軟質的小零件例如：汽車用的煞車零件 '電腦 周邊機器零件以及電氣機器零件之類的軟質的小零件的素 材，爲了提昇生産性，係採用具有優異的被切削性的鋼， 也就是所謂的「快削鋼J 。 這種軟質小零件的切削加工，在工業上，主要都是在 1 0 0 m /分鐘以下的較低速領域來進行的，而且進行切削加 工時的工具，大多採用並未貫施鑛覆處理的局速鋼工具（ 以下，稱「H S S工具」）。而在這種切削加工條件的情況 下，針對於：素材鋼的「被切削性」’基於考慮到要確保 較長的工具壽命，提昇加工精度的觀點，必須要求經過切 削加工後的鋼材表面的拋光面粗糙度要很小’此外，也很 (2) 1307720 重視：切削屑是否具備優異的可斷裂成細屑的性質（以下 ’稱「切削屑處理性」）。特別是良好的切削屑處理性乃 是加工生產線的自動化所不可或缺的，係用來提昇生産性 所必須具備的特性。 習知的快削鋼，係有：大量添加入S以利用MnS來 改善被切削性之含硫快削鋼（以下，稱「含S快削鋼」）、 添加了 Pb之含Pb快削鋼以及含Pb複合快削鋼等。 上述的快削鋼之中，特別是含Pb快削鋼以及含Pb複 合快削鋼，係具備：優異的切削屑處理性，可延長工具壽 命，加工後的鋼材表面的拋光面粗糙度優異等的特性。 因此，這些的含Pb快削鋼係可利用切削加工而被加 工成前述的汽車用的煞車零件、電腦周邊機器零件以及電 氣機器零件之類的軟質的各種小零件的形狀，當成最終製 品來使用。此外，有時候係基於要確保：切削加工後的各 種小零件的強度之目的，必須實施讓表面硬化的滲碳處理 ，使其增加表面硬度之後，才當作最終製品來使用。 然而，近年來因爲對於地球環境問題的高度關心，所 以對於降低含Pb量的快削鋼、或者完全不含Pb的快削鋼 的需求變得極大，例如：在歐洲係發布了： R〇HS指令（On the restriction of the use of certain hazardous substances in electrical and electronic equipment;歐盟電子電機設備 中危害物質禁用指令）、ELV指令（End of Life Vehicle;歐 盟廢車回收指令），嚴格限制鋼材中所含的Pb含量，以質 量％換算時，必須是0.35%以下，因此急需能夠儘可能地 (3) 1307720 減少P b的含量。 此外’ Pb係融點很低，且幾乎不會固熔在鋼中，所 以含有大量的Pb的鋼，在輥軋時很容易產生裂隙。因此 ’即使是基於要穩定的製造鋼的觀點而言，對於：減少 • Pb含量的快削鋼、完全不含Pb的快削鋼的需求也是很大 〇 爲了因應這種需求，專利文獻1〜10係提出可取代： | 含Pb快削鋼以及含Pb複合快削鋼的各種快削鋼的方案。 最爲人知的是如專利文獻1〜4所示的，藉由增加S 量來取代添加Pb，以改善被切削性的低碳含硫快削鋼。 又，如專利文獻5〜1 0所示般地，也有許多解決方案 ，係基於改善被切削性之目的，藉由在含S快削鋼內加入 B、Ti等，來控制鋼中的中介物的形態之快削鋼。 具體而言，專利文獻1係揭示出：藉由含S超過 0.4%而使MnS之不含Pb的「低碳含硫快削鋼」。1307720 (1) Nine, the invention belongs to the technical field of the invention. The present invention relates to a low-carbon sulfur-containing quick-cut steel 'in more detail' relates to: Fast-cut steel (hereinafter referred to as "Pb-containing fast-cut steel") and composite quick-cut steel (hereinafter referred to as "pb-containing composite quick-cut steel") in which Pb is added with other fast-cutting elements such as S and P. Or better machinability of low carbon sulfur-containing quick-cut steel. More specifically, it relates to "having good machinability and excellent carburization property" when cutting with a high-speed steel tool, and because of excellent continuous casting properties, it can be mass-produced at a low price. Low-carbon sulfur-containing quick-cut steel without Pb. [Prior Art] In the past, soft small parts such as automotive parts, computer peripheral parts, and soft parts of electrical parts, etc., have excellent machinability in order to improve productivity. Steel, also known as "fast-cutting steel J." The cutting of such soft small parts is mainly carried out in the lower speed range of below 100 m / min in the industry, and when cutting is performed. Most of the tools used are local speed steel tools (hereinafter referred to as "HSS tools") that are not subjected to mineral coating. In the case of such cutting conditions, the "cutting property" of the material steel is based on the viewpoint of ensuring a long tool life and improving the machining accuracy, and the surface of the steel after the cutting must be required. The roughness of the polished surface is small. In addition, it is very good (2) 1307720. Pay attention to whether the cuttings have excellent properties of breaking into fines (hereinafter referred to as "chip handling"). In particular, good chip handling is indispensable for the automation of the processing line and is a must for improving productivity. The conventional quick-cut steel is a Pb-containing fast-cut steel in which a large amount of sulfur-containing hot-cut steel (hereinafter referred to as "S-cut steel") is added to S to improve the machinability by using MnS, and Pb is added. And Pb composite quick-cut steel. Among the above-mentioned quick-cutting steels, in particular, Pb-containing quick-cut steel and Pb-containing composite quick-cut steel have excellent chip handling properties, can extend tool life, and have excellent polishing surface roughness on the surface of the steel after processing. Characteristics. Therefore, these Pb-containing fast-cutting steels can be processed into the shape of various soft parts such as the above-mentioned automobile brake parts, computer peripheral machine parts, and electrical equipment parts by cutting, and used as final products. . In addition, it is sometimes necessary to use a carburizing treatment for hardening the surface to increase the surface hardness for the purpose of ensuring the strength of various small parts after cutting, and then use it as a final product. However, in recent years, because of the high concern for the global environmental problems, the demand for reducing the Pb-containing fast-cut steel or the Pb-free fast-cutting steel has become enormous, for example, in the European Department: R〇HS On the restriction of the use of certain hazardous substances in electrical and electronic equipment, the ELV Directive (End of Life Vehicle; EU Waste Vehicle Recycling Directive), strictly limits the steel When the Pb content is converted to % by mass, it must be 0.35% or less. Therefore, it is urgent to reduce the content of P b as much as possible (3) 1307720. In addition, the 'Pb system has a very low melting point and hardly solidifies in steel, so steel containing a large amount of Pb is liable to cause cracks during rolling. Therefore, even if it is based on the viewpoint of stable steel production, there is a great demand for: a fast-cut steel with a reduced Pb content and a fast-cut steel that is completely free of Pb. In order to cope with such a demand, Patent Document 1~ The 10 series proposes to replace: | PB-cut steel and various quick-cut steels with Pb composite fast-cut steel. It is most known that, as shown in Patent Documents 1 to 4, a low-carbon sulfur-containing quick-cut steel having improved machinability by increasing the amount of S instead of adding Pb. Further, as shown in Patent Documents 5 to 10, there are many solutions for controlling the medium in the steel by adding B, Ti, etc. to the S-containing hot-cut steel for the purpose of improving the machinability. The shape of the steel is cut quickly. Specifically, Patent Document 1 discloses a "low carbon sulfur-containing quick-cut steel" which does not contain Pb of MnS by containing S in excess of 0.4%.

| 專利文獻2係揭示出：藉由含S超過0·5 0%而使MnS 増量，藉此而謀求改善被切削性的「快削鋼」。 專利文獻3係揭示出：藉由含S : 0.4 %以上，並且加 入Sn，以謀求改善被切削性改善的「低碳含硫快削鋼」 〇 專利文獻4係揭示出：藉由調整硫化物的平均寬度’ 以及線材的降伏比，以改善被切削性之「低碳含硫快削鋼 及其製造方法」。 專利文獻5係揭示出：藉由加入適量的T i、A1以及 (4) 1307720Patent Document 2 discloses a "fast-cut steel" in which MnS is measured by containing S in excess of 0.50%, thereby improving machinability. Patent Document 3 discloses that "low-carbon sulfur-containing quick-cut steel" is improved by improving the machinability by adding S: 0.4% or more and adding Sn. Patent Document 4 discloses that the sulfide is adjusted by adjusting the sulfide. The "average width" of the wire and the ratio of the wire to the "low-carbon sulfur-containing quick-cut steel and its manufacturing method" to improve the machinability. Patent Document 5 discloses that by adding an appropriate amount of Ti, A1, and (4) 1307720

Zr ’使得硫化物系中介物細微化，以改善被切削性之「高 含硫快削鋼j 。 專利文獻6係揭示出：實質上不添加作爲脫氧劑的A1 ’藉由以硫化物系中介物當作環氧硫化物，來改善被切削 性之「含硫有削鋼、該快削鋼之製造方法、以及快削鋼的 機械加工方法」。 專利文獻7〜9係揭示出：藉由調整鋼的成分組成和 • 細微組織’或者使得細微的MnS分散化，以謀求改善被 切削性之「具有優異的被切削性的鋼及其製造方法」或r 具有優異的被切削性的鋼」。 專利文獻1 0係揭示出：由本發明人等所提出的方案 的「低碳快削鋼」，其特徵爲：含有特定量的C、Mn、S 、Ti、Si、Ρ、Α1、Ο及M;Ti與S的含量符合下列（i)式， 且Μη和S的原子比符合下列（ii)式，且含內包著Ti硫化 物或/及Ti碳硫化物的MnS。 # Ti (質量％)/S (質量％)<卜..⑴式；Zr 'fines the sulfide-based intermediaries to improve the machinability of the "high-sulfur-free steel-cutting steel." Patent Document 6 discloses that substantially no A1 as a deoxidizing agent is added by the sulfide system. The material is used as an epoxy sulfide to improve the machinability, "sulphur-containing steel cutting, manufacturing method of the quick-cut steel, and machining method of quick-cut steel." Patent Literatures 7 to 9 disclose "a steel having excellent machinability and a method for producing the same by adjusting the composition of the steel and the fine structure" or dispersing the fine MnS to improve the machinability. Or r has excellent machinability." Patent Document 10 discloses a "low carbon quick-cut steel" according to a proposal proposed by the inventors of the present invention, which is characterized by containing a specific amount of C, Mn, S, Ti, Si, yttrium, lanthanum, yttrium, and M. The content of Ti and S conforms to the following formula (i), and the atomic ratio of Μη and S conforms to the following formula (ii), and contains MnS containing Ti sulfide or/and Ti carbon sulfide. # Ti (质量%) / S (mass%) <卜..(1);

Mn/S 2 1 . . . (Π)式。 〔專利文獻1〕日本特開2000-319753號公報 〔專利文獻2〕日本特開2000-160284號公報 〔專利文獻3〕日本特開2002-249848號公報 〔專利文獻4〕日本特開2003-253390號公報 〔專利文獻5〕日本特開2004-269912號公報 〔專利文獻6〕日本特開2002-363691號公報 〔專利文獻7〕日本特開2004-169051號公報 (5)1307720 〔專利文獻8〕日本特開2004-169052號公報 〔專利文獻9〕日本特開2004-169054號公報 〔專利文獻ίο〕日本特開2003_226933號公報 【發明內容】 〔發明所欲解決之課題〕 前述專利文獻1所揭示的「低碳含硫快削鋼」， 充分地考慮到Mn、S、〇以及n等的成分組成，單純 增加了 S含量而已。因此，並無法獲得較合適的中介 可在於以100m/分鐘以下之較低速領域中使用HSS工 進行切削時，用來同時改善拋光面粗糙度與切削屑處 ’因此，仍然無法確保所期望的良好的被切削性。 專利文獻2所揭示的「快削鋼」，確實可獲得： HSS工具時的被切削性的改善效果。然而，單純只是 S含量而已，並未考慮到硫化物的形態，因此，拋光 糙度變大，有時候無法獲得所期望的較小的拋光面粗 〇 專利文獻3所揭示的「低碳含硫快削鋼」中’提 ◦量的做法會影響到MnS的形態’因而可獲得改善被 性的效果。的確在於具有高含量s的鋼中’爲了將 的形態予以最佳化’提高含0量的做法是很重要的。 ，單純只是提高含〇量的話’將會生成許多粗大的硫 ’因此切削屑處理性會惡化。此外’這個專利文獻3 示的技術，並不是連同氧化物的組成成分也都予以最 並未 只是 物， 具來 理性 使用 增大 面粗 糙度 高含 切削 MnS 然而 化物 所揭 佳化 -9- (6) (6)1307720 。因此，在l〇〇m/分鐘以下的較低速領域中使用HSS工具 進行切削時，無法確保所期望的良好的被切削性。 專利文獻4所揭示的「低碳含硫快削鋼」，只是針對 於直徑爲d的鋼線材，控制由外周面下方0.1mm起至d/8 爲止的區域內的硫化物的形態，較之該區域更深的區域內 的硫化物形態，例如：鋼線材中心部的硫化物形態，則並 未考慮。因此，當使用HSS鑽頭進行加工的這種對於表面 部分以外的部分進行切削加工的情況下，就無法兼具：優 異的切削屑處理性和確保工具的長使用壽命。 專利文獻5所揭示的「高含硫快削鋼」，則會生成： 對於使用HSS工具進行切削而言，不佳形態的硫化物、氧 化物。因此，在l〇〇m/分鐘以下的較低速領域內，使用 HSS工具進行切削時，無法獲得所期望的小拋光面粗糙度 〇 專利文獻6所揭示的「硫黄含有快削鋼」，雖然可藉 由環氧硫化物的存在，來謀求改善被切削性，但是並未精 緻地考慮到鋼的成分組成。因此，無法獲得對於：在 100m/分鐘以下的較低速領域內使用HSS工具進行切削而 言，具有較適合的形態之硫化物以及氧化物，無法確保所 期望的良好的被切削性。 專利文獻7〜9所揭示的「具有優異的被切削性的鋼 」，並未充分地考慮到成分組成，係被設定爲：亦可添加 入對於MnS的形態有很大影響的Al、Ti以及Zr等的成分 元素。這種情況下，並無法獲得：對於使用H S S工具來進 -10- (7) 1307720 行切削而言，具有較適合的形態的硫化物以及 削屑處理性以及拋光面粗糙度會惡化’無法確 良好的被切削性。 專利文獻1 〇所揭示的「低炭素快削鋼」 用超硬工具進行高速切削時的工具壽命較之含 更優異，且可獲得優異的切削屑處理性。但是 分鐘以下的較低速領域內使用HSS工具進行切 ，硫化物形態並不是對於改善被切削性具有幫 所以有時候拋光面粗糙度會變大，而無法所期 面粗糙度。 如上所述，以往被提議的快削鋼’針對於 用的煞車零件、電腦周邊機器零件以及電氣機 的軟質的小零件的素材，所需具備的被切削性 ，亦即，在100m/分鐘以下的較低速領域內使j 進行切削時的工具壽命、切削屑處理性以及拋 之中的至少任何一種特性而言，都較之含Pb 含Pb複合快削鋼更差。也就是說，以往被提 種快削鋼，在1 00m/分鐘以下的較低速領域內彳 具進行切削時的被切削性，無法說是：可與名 之含Pb快削鋼以及含Pb複合快削鋼完全同等 而且，前述之以往所提議的快削鋼也無法 :爲了可以低價地大量生産而在製造階段所需 連續鑄造性、以及製品所需的熱處理特性。亦 保切削加工後的各種小零件的強度之目的，又 氧化物，切 保所期望的 ，的確在使 Pb快削鋼 ，在 100m/ 削的情況下 助的形態， 望的小拋光 作爲：汽車 器零件之類 的各種特性 S HSS工具 光面粗糙度 快削鋼以及 議的任何一 吏用HSS工 Γ大量的Pb 〇 說是具備了 要的良好的 即，基於確 實施滲碳處 -11 - (8) 1307720 理以使其增加表面硬度之後，才作爲最終製 況下’需要求具備良好的「滲碳性」。但是 所提議的快削鋼，未必具有優異的「滲碳性 :爲了可以低價地大量生産，而在製造階段 連續鑄造性」的方面也並不優異。 因此本發明之目的係在於提供：低碳含 種低碳含硫快削鋼即使在未添加 Pb的11 100m/分鐘以下的較低速領域內使用HSS工 的被切削性，係與以往的含Pb快削鋼以及名 鋼同等或更好，且具備優異的滲碳性，並且 鑄造來大量生産。 〔用以解決課題之手段〕 本發明人等，首先使用不含Pb的含S 於：在100m/分鐘以下的較低速領域內，使； 行切削時的被切削性，加以調査。 其結果，獲得了下列（a)的創見。此外， 中的「Μη系硫化物」，如果沒有特別的註 含：MnS、Mn(S、Te)、Mn(S、Se)、Mn(S、 、Se、〇)等，將x當作可與Mn結合之S以 就是Te、Se以及Ο的話，則包含以Mn(S、 表示的Μη的複合化合物。 U)含S快削鋼的情況下，係被認爲：是 的含0(氧）量，來生成粗大的Μη系硫化物 品來使用的情 ，前述的以往 」。而且在於 所需要求的「 硫快削鋼，這 I況下，其在 具進行切削時 Γ Pb複合快削 適合利用連續 快削鋼，針對 目HSS工具進 在以下的説明 明的話’係包 0)以及Mn(s 外的元素’也 X)的化學式來 藉由提高鋼中 因而提昇被切 -12- (9) 1307720 削性。然而，在前述的切削速度領域 切削時，如果單純只是增加含0量的 硫化物粗大化而已，難以提昇被切削 切削屑處理性。 ' 因此，接下來，針對於：在前述 用H S S工具進行切削時，Μη系硫化 之間的關連性進行詳細的檢討。其結 φ 拋光面粗糙度以及切削屑處理性的影 系硫化物的大小而已，其分散的形態 ，因而獲得了下列（b)〜（d)的創見。 (b) 在藉由提高鋼中的含Ο量以偯 地晶析出來的情況下，雖然可使拋光 改善，但是，切削屑處理性卻變差。 硫化物，在進行切削過程中，被當作 形的時候，會成爲應力集中點，而產 φ 起點的龜裂，如此一來，可抑制車刀 up edge )的成長，因而可使得拋光面 改善，且在切削屑剪斷領域內的阻力 力會降低，所以工具壽命得以延長。 粗大化的情況下，龜裂在切削屑内部 所以不至於讓切削屑斷裂，因此，切 (c) 在Μη系硫化物以細微的形態 雖然可改善切削屑處理性，但是拋光 差。亦即’在凝固時因共晶反應而晶 內使用HSS工具進行 話，只會使得Μη系 性，尤其是難以提昇 切削速度領域內的使 物的形態與被切削性 果，係發現了 ：對於 響，不僅是依靠Μη 也會帶來很大的影響 ί得Μη系硫化物粗大 面粗糙度變小而獲得 亦即，粗大的Μ η系 切削屑來承受塑性變 生以Μη系硫化物爲 刃口積屑緣部（built-粗糙度變小而可獲得 被削弱，因而切削阻 另外^ Μ η系硫化物 並不會有效地傳播， 削屑處理性會變差。 晶析出來的情況下， 面粗糙度會變大而變 析出來的許多的細微 -13- (10) 1307720 的Μη系硫化物’因爲變形能力很高，所以在利用鍛造、 輥軋而伸長的狀態下’或者，已經伸長者又受到輥軋而被 斷裂而細微的狀態下’都可以觀察到。這些細微晶析出來 的Μη系硫化物’在切削過程中，作爲切削屑承受到塑性 ' 變形時’很容易變形，所以在切削屑變形時又被加諸了剪 斷應力的情況下’也會變形。然後，以這個變形的Μη系 硫化物當作起點，切削屑會脆化斷裂，而可使得切削屑處 φ 理性獲得改善。另一方面，在車刀刃口積屑緣部（built-up e d g e )周邊的2次剪斷域會受到更強的加工，所以上述的 Μη系硫化物更加地被分斷而更細微化，因此無法產生對 於讓車刀刃口積屑緣部（built-up edge )與切削屑***斷開 很有幫助的裂隙，而使得該更細微化的Μη系硫化物被包 進到車刀刃口積屑緣部的内部。其結果，就無法抑制車刀 刃口積屑緣部的成長，因此，拋光面粗糙度會變大而變差 〇 • (d)由上述（b)以及（c)的創見得知：如果想要改善拋光 面粗糙度使其變得更小，必須是具有：可產生足以令車刀 刃口積屑緣部與切削屑斷開之充分夠大的裂隙作用之Μη 系硫化物，也就是說，即使在2次剪斷域內受到強力加工 也不會***斷開之這種在切削前的狀態下，必須散佈著大 寬度的Μη系硫化物。而且如果既要改善拋光面粗糙度’ 又要改善切削屑處理性的話，則必須讓以Μη系硫化物爲 起點所產生的裂隙有効率地傳播開’因此必須增大可產生 較粗大的裂隙的大寬度的Μ η系硫化物之分布密度。 -14- (11) (11)Mn/S 2 1 . . . (Π). [Patent Document 1] Japanese Laid-Open Patent Publication No. 2000-160284 (Patent Document 2) Japanese Laid-Open Patent Publication No. 2000-160284 (Patent Document 3) JP-A-2002-249848 (Patent Document 4) JP-A-2003-253390 Japanese Laid-Open Patent Publication No. 2004-269691 (Patent Document 7). JP-A-2004-169051 (5) 1307720 [Patent Document 8] JP-A-2004-169052 (Patent Document 9) Japanese Laid-Open Patent Publication No. JP-A No. 2003-226933 (Patent Document No. 2003-226933) SUMMARY OF INVENTION [Problems to be Solved by the Invention] Patent Document 1 discloses The "low-carbon sulfur-containing quick-cut steel" fully considers the composition of Mn, S, niobium, and n, and simply increases the S content. Therefore, it is not possible to obtain a suitable intermediary which can be used to simultaneously improve the roughness of the polished surface and the chip at the time of cutting with an HSS machine in a lower speed range of 100 m/min or less. Therefore, the desired is still not ensured. Good machinability. In the "fast-cut steel" disclosed in Patent Document 2, it is possible to obtain an effect of improving the machinability in the HSS tool. However, it is only the S content, and the form of the sulfide is not taken into consideration. Therefore, the polishing roughness becomes large, and sometimes the desired smaller polished surface roughness cannot be obtained. The "low carbon sulfur" disclosed in Patent Document 3 In the fast-cutting steel, the method of extracting the amount of MnS affects the morphology of the MnS, and thus the effect of improving the properties can be obtained. Indeed, it is important to increase the amount of zero in the steel with a high content of s in order to optimize the morphology. In the case of simply increasing the amount of niobium, 'a lot of coarse sulfur will be produced', so the chip handling property will deteriorate. In addition, the technique shown in this Patent Document 3 is not the most inconsistent with the composition of the oxide, and it is used rationally to increase the surface roughness and include the cutting MnS. 6) (6) 1307720. Therefore, when cutting with an HSS tool in a lower speed range of l〇〇m/min or less, the desired good machinability cannot be ensured. The "low-carbon sulfur-containing quick-cut steel" disclosed in Patent Document 4 is only for the steel wire having a diameter d, and controls the form of sulfide in a region from 0.1 mm to d/8 below the outer peripheral surface. Sulfide forms in deeper areas of the area, such as sulfide forms in the center of steel wire, are not considered. Therefore, when the part other than the surface portion is machined using the HSS drill, it is impossible to combine: excellent chip handling property and long tool life. The "high-sulfur-free-cut steel" disclosed in Patent Document 5 produces: a sulfide or an oxide of a poor form for cutting with an HSS tool. Therefore, in the lower speed region of l〇〇m/min or less, when the HSS tool is used for cutting, the desired small polished surface roughness cannot be obtained. The "Sulphur contains fast-cut steel" disclosed in Patent Document 6, although The machinability can be improved by the presence of the epoxy sulfide, but the composition of the steel is not carefully considered. Therefore, it is not possible to obtain a sulfide or an oxide having a suitable form in a lower speed region of 100 m/min or less, and it is impossible to ensure a desired good machinability. The "steel having excellent machinability" disclosed in Patent Documents 7 to 9 does not sufficiently take into consideration the composition of the components, and may be added to Al, Ti, which have a great influence on the form of MnS, and Component elements such as Zr. In this case, it is not possible: for the use of the HSS tool to cut into the -10- (7) 1307720 row, the sulfide with a more suitable form and the shaving treatment and the roughness of the polished surface will deteriorate. Good machinability. "Low-carbon quick-cutting steel" disclosed in Patent Document 1 工具 The tool life at the time of high-speed cutting with a super-hard tool is superior to that of the tool, and excellent chip handling property can be obtained. However, HSS tools are used for cutting in the lower speed range below minutes. The sulfide form is not helpful for improving the machinability. Sometimes the roughness of the polished surface will become large and the surface roughness will not be achieved. As described above, the fast-cut steel that has been proposed in the past is required to have the machinability required for the brake parts, the computer peripheral parts, and the soft small parts of the electric machine, that is, below 100 m/min. In the lower speed range, at least one of the tool life, chip handling, and throwing during cutting is worse than that of Pb-containing Pb composite quick-cut steel. In other words, in the past, when the quick-cut steel was introduced, the machinability in the lower speed range of 100 m/min or less was not able to be said: it could be said to be Pb-free steel with Pb and Pb-containing The composite quick-cut steel is completely equivalent, and the previously proposed quick-cut steel cannot be used for continuous casting properties at the manufacturing stage and heat treatment characteristics required for the product in order to be mass-produced at low cost. It also guarantees the strength of various small parts after cutting, and the oxides, which are expected to be cut, are indeed in the form of Pb fast cutting steel, assisted in the case of 100m/sharpening, and small polishing as: Various features such as parts and components S HSS tool smooth surface roughness cutting steel and any of the use of HSS workmanship of a large number of Pb 〇 said that it is necessary to be good, that is, based on the implementation of carburizing point -11 - (8) 1307720 After the surface hardness is increased, it is required to have good "carburization" as the final condition. However, the proposed quick-cut steel does not necessarily have excellent "carburizing properties: it is not excellent in terms of continuous casting at the manufacturing stage in order to be mass-produced at a low price." Therefore, the object of the present invention is to provide a low carbon-containing low-carbon sulfur-containing quick-cut steel, even if the HSS workability is used in a lower-speed region of 11 100 m/min or less in which no Pb is added, and the conventional Pb fast-cut steel and famous steel are equal or better, have excellent carburizing properties, and are cast to mass production. [Means for Solving the Problem] The inventors of the present invention first investigated the machinability at the time of cutting in the lower-speed region of 100 m/min or less using Pb-free S-containing material. As a result, the following (a) creation was obtained. In addition, the "Μη sulfide" in the middle is not specifically included: MnS, Mn (S, Te), Mn (S, Se), Mn (S, Se, Se), etc. When S combined with Mn is Te, Se, and yttrium, it contains a composite compound of Mn (S, which represents Μη. U). In the case of S-containing steel, it is considered to be: 0 (oxygen). The amount is used to generate a large Μ 系 vulcanized article to be used, as described above. In addition, it is required to use the "sulphur fast-cutting steel. In this case, the ΓPb composite quick-cutting is suitable for continuous and quick-cutting steel when cutting. For the purpose of the HSS tool, please refer to the following description." And the chemical formula of Mn (the element other than s 'X) is improved by the improvement of the steel and thus the cut-cut 12-(9) 1307720. However, when cutting in the aforementioned cutting speed field, if it is simply added The amount of sulfide in the amount of 0 is coarsened, and it is difficult to improve the handling property of the cutting chips. Therefore, the following is a detailed review of the correlation between the Μ-based vulcanization when cutting with the HSS tool. The roughness of the polished surface of the φ polishing surface and the size of the sulphide of the chip processing property, the dispersion form, and thus the following (b) to (d) are obtained. (b) By increasing the content of the steel In the case where the amount of cerium is crystallized, the polishing can be improved, but the handling property of the chips is deteriorated. The sulfide is a stress concentration point when it is shaped as a cutting process. Produce The crack at the starting point, in this way, suppresses the growth of the turning edge of the turning tool, thereby improving the polishing surface and reducing the resistance in the field of chip cutting, so that the tool life is prolonged. In the case where the crack is inside the cuttings, the chips are not broken. Therefore, (c) the Μ-type sulfide can improve the chip handling property in a fine form, but the polishing is poor. The eutectic reaction and the use of the HSS tool in the crystal will only make the Μ 系 system, especially the shape and the machinability of the object in the field of cutting speed. It is found that, for the ring, it is not only relying on Μη Will have a great impact. The roughness of the Μ-type sulfide coarse surface is reduced, that is, the coarse Μ-type cutting chips are used to withstand plastic deformation, and the Μ-type sulfide is used as the edge of the cutting edge. - the roughness becomes small and can be weakened, so that the cutting resistance is not effectively propagated, and the chip treatment property is deteriorated. In the case of crystallization, the surface roughness is changed. Many of the fine -13-(10) 1307720 Μη sulfides that have been analyzed are highly deformed, so they are stretched by forging or rolling, or the stretched ones are rolled again. It can be observed in the state of being broken and subtle. These fine crystallized Μη sulfides are easily deformed during the cutting process as the chips undergo plastic deformation, so when the chips are deformed When it is added to the shear stress, it will also deform. Then, with this deformed Μ-type sulfide as the starting point, the chips will be brittle and fracture, and the φ rationality of the cuttings can be improved. On the other hand, in the secondary shearing area around the built-up edge of the turning edge, the above-mentioned Μ 系 sulfide is more broken and finer, so it cannot be produced. It is a crack that is helpful for the built-up edge of the turning edge to break off the cuttings, so that the finer Μ-type sulfide is wrapped into the edge of the cutting edge of the turning edge. internal. As a result, it is impossible to suppress the growth of the edge portion of the blade edge, and therefore, the roughness of the polishing surface becomes large and deteriorates. (d) It is known from the above (b) and (c): If desired To improve the roughness of the polished surface to make it smaller, it must have: Μ 系 sulfide which can produce enough sufficient crack to break the edge of the blade edge and the cutting chips, that is, even In the state before cutting, which is subjected to strong processing in the second shearing zone, it is necessary to disperse a large-width Μ-type sulfide in the state before cutting. Moreover, if it is necessary to improve the roughness of the polished surface and to improve the handling of the chips, it is necessary to efficiently spread the cracks generated from the Μ-based sulfide as a starting point, so it is necessary to increase the coarse cracks. The distribution density of large width Μ 硫化 sulfides. -14- (11) (11)

1307720 因此，更進一步地針對於：藉由增加大寬度 硫化物的分布密度，以資提高拋光面粗糙度與切 性的兩種特性的條件，進行詳細檢討。其結果’ (e)〜（i)的創見，而且針對於工具壽命則是獲得 創見。 (e)爲了要增加大寬度的Μη系硫化物的分布 須增大Μη系硫化物的絶對量，因此，必須以超 範圍來含有S。 (0針對於大寬度的Μη系硫化物，在於與 Μη系硫化物之間的平均距離也就是「最短平均 離」很小的情況下，可有效率地讓裂隙傳播出去 切削屑的分斷開，即使在不含Pb的情況下，亦 含Pb快削鋼以及含Pb複合快削鋼同等的切削屑 (g)爲了要增加大寬度的Μη系硫化物的分布 須因應含S量，來使大多數之在凝固階段可作肩 化物的生成核心的Μη系氧化物分散開，爲了猜 果，不僅要增大含S量、含0量，也必須將鋼纪 ，特別是Mn、S以及0的含量平衡點以及Α1、 與雜質中的Ca、Mg、Ti、Zr以及REM的含量3 。此外，Μη系氧化物的生成頻度係與Μη和Ο ，也就是「Μηχ〇」相關連。 (h)先令在凝固的早期階段所生成的Μη系 分的密度分布’以這個Μη系氧化物當作生成 晶反應而生成Μη系硫化物，可使得寬度大且 的Μη系 削屑處理 獲得下列 下列⑴的 「密度，必 過0.4%的 最靠近的 '粒子間距 :而助長了 ;可獲得與 處理性。 ί密度，必 ;Μ η系硫 ί得這個結 J成分組成 S i的含量 >以適量化 的濃度積 I化物以充 ;5利用偏 €短平均粒 -15- (12) 1307720 子間距離很小的Μη系硫化物，以較大的分布密度存在。 (i) Ν並不會影響到較適合用來改善被切削性之μ η系 硫化物的形態以及氧化物組成，係固熔在肥粒鐵中來提高 切削屑處理性，所以最好是含有充分的量。 (j) 如果在肥粒鐵粒内大量地分散著細微的Μη系氧化 物的話，即可改善工具壽命而使其延長。 本發明係依據上述的創見而開發完成的，其要旨係在 於下列（1)〜（4)所示的低碳含硫快削鋼。 (1) 一種低碳含硫快削鋼，其特徵爲：以質量％換算， 係包含C : 0.05%以上且未滿0.20%、Si :未滿0.02%、Μη :0.7〜2.2%、Ρ: 0.005 〜0.25%、S:超過 0.40 % 且 0.60% 以下、Α1:未滿 0.003 %、0: 0.0090 〜0.0280%' Ν: 0.003 0〜0.0250%，其餘部分係由Fe以及雜質所組成，雜 質中的Ca、Mg、Ti、Zr以及REM係Ca :未滿0.001 %、 M g :未滿 0 . 〇 0 1 % ' T i :未滿 0.0 0 2 %、Z r :未滿 0.0 0 2 % 以 及REM :未滿0.001%，並且符合下列（1)式以及（2)式， Μηχ〇>〇·0 1 8 · · · (1)式； 2.5<Mn/(S + 〇)<3 .5 . · · (2)式， 在（1)式以及（2)式中的元素符號係代表：以該元素的 質量％之在於鋼中的含量。 (2) 如上述（1)所述的低碳含硫快削鋼，其中的N含量 ，以質量％換算，係N : 0.0 0 6 0〜0 . 〇 2 5 0 %。 (3) 如上述（1)或（2)所述的低碳含硫快削鋼，其中係含 T e : 0.0 0 0 5 〜0 · 0 3 %、S η : 0 · 0 0 1 % 以上且未滿 0.5 0 % 以及 -16- (13) (13)1307720 S e : 〇 · 〇 〇 〇 5 %以上且未滿0.3 0 %之中的1種以上，來取代 F e的一部分。 (4)如上述（1)至（3)之中的任何一種所述的低碳含硫快 削鋼，其中係含 C u : 0 _ 0 1 〜1 _ 〇 %、N i : 0 _ 0 1 〜1 · 0 % ' c r : 〇 . 0 1〜1 . 0 %以及 Mo : 0.0 1〜0 · 5 %之中的 1種以上，來取 代F e的一部分。 以下，係將上述（1)〜（4 )的低碳含硫快削鋼的發明， 分別稱爲「本發明（1 )」〜「本發明（4)」。而且有時候也 總稱爲「本發明」。 此外，本發明所稱的「REM」係爲Sc、Y以及類鑭元 素之合計17種元素的總稱，REM的含量係指：上述元素 的合計含量。 〔發明効果〕 本發明的鋼，雖然是未添加Pb的「可善待地球環境 的快削鋼」，但在1 〇〇m/分鐘以下的較低速領域內使用 HSS工具進行切削時，係具有與以往的含Pb快削鋼、及 複合添加了 Pb和S、P等其他的快削元素之含Pb複合快 削鋼同等級以上的良好的被切削性，也就是說，工具壽命 長、良好的切削屑處理性以及具有小抛光面粗糙度，且滲 碳性優異，並且連續鑄造性極優，所以可低價地大量生産 。因此，可作爲汽車用的煞車零件、電腦周邊機器零件以 及電氣機器零件之類的軟質小零件的素材來加以利用。 -17- (14) 1307720 【實施方式】 〔實施本發明之最佳形態〕 首先，說明本發明的低碳含硫快削鋼的化學組成以及 限定其含量的理由。此外，在以下的説明中，各元素的含 ' 量的「％」標示，係意指「質量％ j 。 C : 0.05%以上且未滿0.20% C係對於被切削性有很大影響的重要元素。在重視被 φ 切削性的用途的鋼的情況下，如果含C爲0.20%以上的話 ，鋼的強度會變高而使得被切削性變差。然而，若C的含 量未滿0_05%的話，鋼會太過於軟質，在進行切削中會產 生拉扯現象，反而會促進工具磨損，而且拋光面粗糙度也 會變大而變差。因此，C的含量選定爲〇.〇 5 %以上且未滿 0.2 0 %。此外，爲了獲得更良好的被切削性，C的含量選 定爲0.06〜0.18 %爲宜。 S i :未滿 0.0 2 % • Si係與0(氧）的親和性很強之強力的脫氧元素，在含 有0.02%以上的情況下，無法獲得對於改善被切削性較爲 適合的Μη系硫化物的形態以及氧化物組成，所以在 100m/分鐘以下的較低速領域內之利用HSS工具進行切削 時的被切削性會變差。因此，Si的含量選定爲未滿0.02% 。此外’ S i對於Μη系硫化物的形態以及氧化物組成有很 大的影響，所以不僅不要添加，在進行精煉鋼時，必須儘 可能地予以去除。如果想要獲得更優異的被切削性，S i的 含量係選定爲未滿0.01 %爲宜。 -18- (15) 1307720 Μη : 0.7 〜2.2% Μη係與S —起形成Μη系硫化物而對於被切削性有 很大影響的重要兀素。如果其含量未滿0.7 %的話，Μη系 硫化物的絶對量會不足’無法獲得所期望的良好的被切削 性，而且熱間加工性也會變差。Μη也具有可提高滲碳性 的作用’所以如果想要獲得良好的滲碳性的情況下，只要 提高Μη的含量即可，但是因爲Μη除了是Μη系硫化物 形成元素之外，又對於脫氧也具有助益，所以如果只是基 於改善滲碳性之目的，單純地提高Μη的含量的話，也無 法獲得所期望的中介物形態。如果想要獲得所期望的中介 物形態，必須先充分地考慮到與S、0(氧）的質量平衡度之 後，才來添加Μη。然而，即使是在這種情況下，Μη的含 量若超過2.2%的話，還是無法獲得所期望的中介物形態 ，被切削性會變差。因此，Μη的含量選定爲0.7〜2.2%。 此外，爲了要兼具所期望的良好的被切削性和良好的滲碳 性，Μη的含量係選定在1.2〜1 .8%爲宜。 此外，上述的「Μη系硫化物」係指：MnS以及如 Mn(S、Te)、Mn(S、Se)、Mn(S、0)及 Mn(S、Se、0)等所 表示般的，X代表S以外之可與Μη結合的元素也就是Te 、Se以及Ο，以Mn(S、X)的化學式來表示的Μη的複合 化合物。 Ρ: 0.005 〜0.25% Ρ係具有降低粒界的強度’提高被切削性的作用。若 想要獲得前述的効果，必須將Ρ的含量選定爲0.005%以 -19- (16) 1307720 上。另一方面，如果P的含量過度的話，鋼的強度會變高 ，反而會導致被切削性的降低，特別是若P的含量超過 0.25%的話，強度變得太高，被切削性的降低會很顯著。 此外，P的含量超過0.2 5 %的情況下，因爲會助長鋼塊的 偏晶析出，所以也會造成熱間加工性的降低。因此，P的 含量選定爲0.005〜0.25%。爲了要穩定地獲得更優異的被 切削性，P的含量係選定爲0.03〜0.1 5 %爲宜。 S :超過0.4 0 %且0.6 0 %以下 j S係與Μη —起形成Μη系硫化物以資提高被切削性 所必須的元素。利用Μη系硫化物來提高被切削性的効果 ，不僅係依據其生成量，也會隨著形態以及分散狀態而改 變。因此，S的含量、以及Μη和0(氧）的含量的平衡度是 很重要的，但是如果S的含量是0.4 0 %以下的話，縱使將 Μη以及〇(氧）的含量的平衡度適量化，也無法獲得充分量 的Μη系硫化物，無法獲得可用以得到所期望的良好的被 切削性之Μη系硫化物的分散形態。此外，在一般的情況 下，S的含量若超過0.3 5%的話，熱間加工性會降低，所 以會成爲在鑄片内部形成所謂的「内部斷裂」的主因，但 是藉由將Μη以及0(氧）的含量的平衡度予以適量化，S的 含量即使是超過〇 . 3 5 %的情況下，也不會引起内部斷裂的 現象，可提高被切削性。然而，S的含量若超過0.60 %的 情況下，則必須大量含有Μη，以使得熱間延性不會產生 惡化，但是Μη係當作脫氧元素來作用，所以無法確保充 分的氧量，因此有損Μ η系硫化物的形態，實質上是難以 -20- (17) 1307720 獲得所期望的Μη系硫化物的形態以及分散狀態。此外， 含量若超過0.60%之過量添加S的話，將會因爲良品率的 惡化導致製造成本上昇。因此，S的含量選定爲超過 0.40%且0_60%以下。此外，若想要更穩定地確保優異的 被切削性，並且不會讓製造性惡化地獲得所期望的Μη系 硫化物的形態的話’ S含量係選定爲0.4 5〜0.5 5 %爲宜。 Α1 :未滿 0.003 % Α1是與0(氧）的親和性很強之強力的脫氧元素，在含 有0.0 0 3 %以上的情況下，無法獲得適合改善被切削性的 Μη系硫化物的形態以及氧化物組成，所以在1 0 0 m/分鐘 以下的較低速領域下利用HSS工具進行切削時的被切削性 會惡化。因此，乃將A1的含量設定在未滿0.003%。此外 ，A1會對於Μη系硫化物的形態以及氧化物組成帶來很大 的影響，所以不僅是不要添加，而且在進行精煉時也必須 儘可能地予以除去。爲了獲得更優異的被切削性，Α1的含 量是設定在未滿0.002%爲宜。 Ο ： 0.0090 - 0.0280% 除了將Μη以及S的含量的平衡予以適量化之外，藉 由提高0(氧）的含量，可改變Μη系硫化物的形態，進而 可改善被切削性。然而，〇的含量若未滿〇 . 0 0 9 0 %的話， 無法得到用以獲得所期望的良好的被切削性的中介物形態 ，無法確保充分的被切削性。另一方面，若0的含量超過 0.02 8 0%的話，不僅無法獲得所期望的中介物形態，也會 產生粗大的氧化物，導致在進行輥軋時發生龜裂。因此， -21 - (18) 1307720 乃將Ο的含量設定在0.0090〜0.028 0%。此外’ 〇的含量 ，爲了要穩定地確保所期望的中介物形態、分散狀態，係 以設定在0.0100〜0.0200%的範圍爲宜。 Ν: 0.0030 〜0.0250% 即使提高Ν的含量，也不會影響適合改善被切削性的 Μη系硫化物的形態以及氧化物組成，而且在實質上並不 含Al、Ti的本發明中，幾乎不會形成硬質的Al、Ti的氮 化物，所以N係以固熔在肥粒鐵中的狀態存在。固熔在上 述肥粒鐵中的N係具有提高切削屑處理性的作用。然而， 若在N的含量未滿0.003 0%的情況下，無法獲得充分地提 高切削屑處理性的効果。另一方面，如果N的含量超過 0_〇2 5 0%的話，不僅前述的効果趨於飽和，也會導致製造 成本的上昇。因此，係將 N的含量設定在 0.0030〜 0.02 5 0%。此外，若想獲得良好的被切削性的情況下，含 N量係0.0060%以上爲宜，若想更有効果地獲得良好的被 切削性的情況下，含N量係0.0 0 8 0 %以上爲宜。 本發明的低碳含硫快削鋼中，雜質中的Ca、Mg、Ti 、Zr以及REM的含量係限制在下列的範圍。 C a :未滿 0 · 0 0 1 %、M g :未滿 0 · 0 0 1 %、T i :未滿 0.002%、Zr:未滿 0.002%以及 REM:未滿 0.001% 在一般的快削鋼中，Ca、Mg、Ti、Zr以及REM都是 被添加作爲用來改善被切削性的元素。然而，從上述的 Ca至REM的各元素，都會對於Μη系硫化物的形態、氧 化物組成以及這些中介物的分散狀態帶來不良影響，在 -22- (19) 13077201307720 Therefore, it is further directed to: a detailed review by increasing the distribution density of large-width sulfides to improve the conditions of the roughness and the cutness of the polished surface. The result is a creative idea of 'e) to (i), and it is acquired for tool life. (e) In order to increase the distribution of the Μ-type sulfide of a large width, the absolute amount of the Μ-type sulfide must be increased. Therefore, it is necessary to contain S in an excessive range. (0) For large-width Μ-type sulfides, in the case where the average distance between the Μ-type sulfides and the 最η-based sulfides is small, the "shortest average separation" is small, and the cracks can be efficiently propagated out of the cuttings. Even in the case of Pb-free, Pb-cut steel and Pb-containing composite-cut steel (g) are required to increase the distribution of large-width Μ-type sulfides in order to contain the amount of S. Most of the Μ-type oxides which can be used as the core of the formation of the shoulder in the solidification stage are dispersed. In order to guess, it is necessary to increase not only the amount of S, but also the amount of 0, and also the steel, especially Mn, S and 0. The content balance point and the content of Ca, Mg, Ti, Zr and REM in Α1 and impurities are 3. In addition, the frequency of formation of Μη oxide is related to Μη and Ο, that is, "Μηχ〇". The density distribution of the Μ 系 生成 生成 在 在 在 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 以 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度 密度(1) "The density must exceed 0.4%. 'particle spacing: and promoted; available and handleability. ί density, must; η η sulphur 得 get this junction J component composition S i content> with a moderate concentration of product I charge to charge; 5 use €η Short average particle -15- (12) 1307720 Μη sulfide with a small distance between sub-mass, which exists at a large distribution density. (i) Ν does not affect the μ which is more suitable for improving the machinability. The form and oxide composition of the η-based sulfide are solid-melted in the ferrite iron to improve the chip handling property, so it is preferable to contain a sufficient amount. (j) If a large amount of fine particles are dispersed in the ferrite particles The present invention is developed in accordance with the above-mentioned novelty, and the present invention is based on the low carbon sulfur-containing rapid cutting shown in the following (1) to (4). (1) A low-carbon sulfur-containing quick-cutting steel characterized by containing C: 0.05% or more and less than 0.20%, Si: less than 0.02%, and Μη: 0.7 to 2.2%, in terms of mass%. Ρ: 0.005 to 0.25%, S: more than 0.40% and 0.60% or less, Α1: less than 0.003%, 0: 0.0090 to 0.0280%' Ν: 0 .003 0~0.0250%, the rest is composed of Fe and impurities, Ca, Mg, Ti, Zr and REM in the impurities Ca: less than 0.001%, M g : less than 0. 〇0 1 % ' T i : less than 0.0 0 2 %, Z r : less than 0.0 0 2 % and REM : less than 0.001%, and conforms to the following formulas (1) and (2), Μηχ〇>〇·0 1 8 · · (1) Formula; 2.5 < Mn / (S + 〇) <3 .5 . · · (2) Formula, the element symbol in (1) and (2) represents: The % by mass is the content in the steel. (2) The low carbon sulfur-containing quick-cut steel according to the above (1), wherein the N content is converted by mass %, and is N: 0.0 0 6 0 to 0. 〇 2 5 0 %. (3) The low-carbon sulfur-containing quick-cut steel according to the above (1) or (2), which contains T e : 0.0 0 0 5 〜 0 · 0 3 %, S η : 0 · 0 0 1 % or more And less than 0.5 0 % and -16-(13) (13) 1307720 S e : 〇· 〇〇〇 5% or more and less than 0.3% of the total, instead of a part of F e . (4) The low carbon sulfur-containing quick-cut steel according to any one of the above (1) to (3), wherein C u : 0 _ 0 1 〜1 _ 〇%, N i : 0 _ 0 1 to 1 · 0 % ' cr : 〇. 0 1 to 1 . 0 % and Mo : 0.0 1 to 0 · 5 % One or more of them replaces a part of F e . Hereinafter, the inventions of the low carbon sulfur-containing quick-cut steels of the above (1) to (4) are referred to as "the present invention (1)" to "the present invention (4)", respectively. And sometimes it is also called "the invention". Further, the "REM" referred to in the present invention is a general term for a total of 17 elements of Sc, Y, and a quinone-like element, and the content of REM means the total content of the above elements. [Effect of the Invention] The steel of the present invention is a "fast-cut steel that can treat the global environment" without adding Pb. However, when the HSS tool is used for cutting in a lower speed region of 1 〇〇m/min or less, Good machinability with Pb-based fast-cut steel with Pb-cut steel and other fast-cutting elements such as Pb, S, P, etc., that is, long tool life and good The chip treatment property and the small polished surface roughness, and excellent carburization property, and excellent continuous casting property, can be mass-produced at low cost. Therefore, it can be used as a material for brake parts for automobiles, parts for computer peripherals, and soft small parts such as electrical equipment parts. -17- (14) 1307720 [Embodiment] [Best Mode for Carrying Out the Invention] First, the chemical composition of the low-carbon sulfur-containing quick-cut steel of the present invention and the reason for limiting the content thereof will be described. In addition, in the following description, the "%" of each element contains the "%", which means "mass% j. C: 0.05% or more and less than 0.20%. C is important for the machinability. In the case of steel which is used for the use of φ machinability, if the content of C is 0.20% or more, the strength of the steel becomes high and the machinability is deteriorated. However, if the content of C is less than 0_05%. Steel will be too soft, which will cause pulling during cutting, which will promote the wear of the tool, and the roughness of the polished surface will become larger and worse. Therefore, the content of C is selected to be more than 5%. In addition, in order to obtain better machinability, the content of C is preferably selected from 0.06 to 0.18%. S i : less than 0.0 2 % • The affinity between the Si system and 0 (oxygen) is strong. When a strong deoxidizing element is contained in an amount of 0.02% or more, the form and oxide composition of the Μ 硫化 sulfide which is suitable for improving the machinability are not obtained, so that it is used in a lower speed range of 100 m/min or less. The machinability of the HSS tool during cutting will change. Therefore, the content of Si is selected to be less than 0.02%. In addition, 'S i has a great influence on the morphology and oxide composition of the Μ 系 sulfide, so it is not necessary to add it, and it is necessary to carry out the steel as much as possible. It is removed. If it is desired to obtain more excellent machinability, the content of S i is preferably less than 0.01%. -18- (15) 1307720 Μη : 0.7 ～2.2% Μ 系 and S form a Μ 系 system An important element of sulphide which has a great influence on the machinability. If the content is less than 0.7%, the absolute amount of Μ 系 sulphide may be insufficient to obtain the desired good machinability, and hot interfacial processing The properties are also deteriorated. Μη also has the effect of improving the carburization property. Therefore, if it is desired to obtain good carburization properties, it is only necessary to increase the content of Μη, but since Μη is a Μη sulfide-forming element. In addition, it is also helpful for deoxidation, so if the content of Μη is simply increased based on the purpose of improving carburization, the desired intermediate form cannot be obtained. In the form of the intermediary, it is necessary to fully consider the mass balance with S and 0 (oxygen) before adding Μη. However, even in this case, if the content of Μη exceeds 2.2%, it is still not available. The desired form of the medium is deteriorated in the machinability. Therefore, the content of Μη is selected to be 0.7 to 2.2%. Further, in order to achieve both desired good machinability and good carburization, the content of Μη Preferably, the above-mentioned "Μη-based sulfide" means: MnS and such as Mn (S, Te), Mn (S, Se), Mn (S, 0), and Mn. (S, Se, 0) and the like, X represents a compound other than S which can be combined with Μη, that is, Te, Se, and Ο, and a composite compound of Μ η represented by a chemical formula of Mn (S, X). Ρ: 0.005 to 0.25% lanthanide has a function of lowering the grain boundary' to improve machinability. If you want to achieve the above results, you must select the content of bismuth to 0.005% to -19- (16) 1307720. On the other hand, if the content of P is excessive, the strength of the steel becomes high, and the machinability is lowered. In particular, if the content of P exceeds 0.25%, the strength becomes too high, and the machinability is lowered. Very significant. Further, when the content of P exceeds 0.25%, the unevenness of the steel block is promoted, so that the inter-heat workability is also lowered. Therefore, the content of P is selected to be 0.005 to 0.25%. In order to stably obtain more excellent machinability, the content of P is preferably selected from 0.03 to 0.15%. S: more than 0.40% and 0.60% or less The j S system and Μη together form an element which is necessary for the formation of Μ 硫化 sulfide to improve machinability. The effect of improving the machinability by using Μ 硫化 sulfide is not only dependent on the amount of formation but also on the form and dispersion state. Therefore, the balance of the content of S and the content of Μη and 0 (oxygen) is important, but if the content of S is 0.4% or less, the balance between the contents of Μη and 〇(oxygen) is quantified. Also, a sufficient amount of Μ-based sulfide cannot be obtained, and a dispersion form of the Μ-based sulfide which can be used to obtain desired good machinability cannot be obtained. In addition, in general, when the content of S exceeds 0.35%, the hot-intermediate workability is lowered, so that the so-called "internal fracture" is formed inside the cast piece, but by Μη and 0 ( The balance of the content of oxygen is appropriately quantified, and even if the content of S exceeds 0.35%, the internal fracture does not occur, and the machinability can be improved. However, when the content of S exceeds 0.60%, Μη must be contained in a large amount so that the thermal ductility does not deteriorate, but Μη acts as a deoxidizing element, so that a sufficient amount of oxygen cannot be secured, and thus it is impaired. The form of the η-based sulfide is substantially difficult to obtain the desired form of the Μ-based sulfide and the dispersed state of -20-(17) 1307720. Further, if S is added in an excess amount of more than 0.60%, the manufacturing cost will increase due to deterioration of the yield. Therefore, the content of S is selected to be more than 0.40% and 0_60% or less. In addition, it is preferable that the 'S content is selected to be 0.4 5 to 0.5 5 %, if it is desired to ensure excellent machinability more stably and to obtain a desired form of the Μ 系 sulfide without deteriorating the manufacturability. Α1 : less than 0.003 % Α1 is a strong deoxidizing element having a strong affinity with 0 (oxygen). When it contains 0.03 % or more, the form of the Μ 系 sulfide suitable for improving the machinability cannot be obtained. Since the oxide composition is used, the machinability at the time of cutting by the HSS tool in the lower speed range of 100 m/min or less is deteriorated. Therefore, the content of A1 is set to less than 0.003%. In addition, A1 has a great influence on the morphology and oxide composition of the Μ 硫化 sulfide, so it is not only added, but must be removed as much as possible during refining. In order to obtain more excellent machinability, the content of Α1 is preferably set to less than 0.002%. Ο : 0.0090 - 0.0280% In addition to the balance between the contents of Μη and S, by increasing the content of 0 (oxygen), the form of the Μ 硫化 sulfide can be changed, and the machinability can be improved. However, if the content of niobium is less than 0.90%, an intermediate form for obtaining a desired good machinability cannot be obtained, and sufficient machinability cannot be ensured. On the other hand, when the content of 0 exceeds 0.02 80%, not only the desired intermediate form but also coarse oxides are generated, and cracking occurs during rolling. Therefore, -21 - (18) 1307720 sets the content of cerium to 0.0090 to 0.028 0%. Further, the content of ruthenium is preferably set in the range of 0.0100 to 0.0200% in order to stably ensure the desired form and dispersion state of the intermediate. Ν: 0.0030 to 0.0250% Even if the content of niobium is increased, the morphology and oxide composition of the niobium-based sulfide suitable for improving the machinability are not affected, and in the present invention which does not substantially contain Al or Ti, hardly Since a hard Al and Ti nitride is formed, the N system exists in a state of being solid-melted in the ferrite iron. The N-series which is solid-melted in the above ferrite iron has an effect of improving chip handling properties. However, if the content of N is less than 0.003 0%, the effect of sufficiently improving the chip treatment property cannot be obtained. On the other hand, if the content of N exceeds 0_〇250%, not only the aforementioned effects tend to be saturated, but also the manufacturing cost rises. Therefore, the content of N is set to 0.0030 to 0.02 50%. In addition, when it is desired to obtain good machinability, the N content is preferably 0.0060% or more, and if it is desired to obtain good machinability more effectively, the N content is 0.080% or more. It is appropriate. In the low carbon sulfur-containing quick-cut steel of the present invention, the contents of Ca, Mg, Ti, Zr and REM in the impurities are limited to the following ranges. C a : less than 0 · 0 0 1 %, M g : less than 0 · 0 0 1 %, T i : less than 0.002%, Zr: less than 0.002%, and REM: less than 0.001% in general fast cutting In steel, Ca, Mg, Ti, Zr, and REM are all added as elements for improving machinability. However, the elements from the above-mentioned Ca to REM adversely affect the morphology, oxide composition, and dispersion state of these intermediates, in -22- (19) 1307720

1 00m/分鐘以下的較低速領域下’利用HS S工具進行切削 時的被切削性會降低。尤其是雜質中的上述的Ca、Mg、 Ti、Zr以及REM，如果Ca、Mg以及REM的其中一種的 含量是0.001%以上，Ti以及Zr的其中一種的含量是 ' 0.0 0 2 %以上的情況下，在前述的切削速度領域下使用H S S 工具進行切削時的被切削性的降低會趨於明顯。因此，Ca 、Mg、Ti、Zr以及REM的雜質中的含量必須限定爲Ca : _ 未滿 0.001%、Mg :未滿 0.00 1%、Ti :未滿 0.002%、Zr : 未滿0.002%以及REM :未滿0.00 1 %。雜質中的上述Ca 'In the lower speed range of 1 00 m/min or less, the machinability when cutting with the HS S tool is lowered. In particular, in the above-mentioned Ca, Mg, Ti, Zr, and REM of the impurities, if the content of one of Ca, Mg, and REM is 0.001% or more, the content of one of Ti and Zr is '0.0 0 2% or more. Next, the reduction in machinability when cutting using the HSS tool in the aforementioned cutting speed field tends to be conspicuous. Therefore, the content of impurities in Ca, Mg, Ti, Zr and REM must be limited to Ca: _ less than 0.001%, Mg: less than 0.001%, Ti: less than 0.002%, Zr: less than 0.002%, and REM : Less than 0.00 1 %. The above Ca ' in impurities

Mg、Ti、Zr以及REM的任何一種均爲0.000 5 %以下爲宜 〇 此外，如前所述，「REM」是S c、Y以及類鑭元素的 合計1 7元素的總稱，rEm的含量係指上述元素的合計含 量。 Μη與Ο的濃度積（Μηχ〇):超過0.018 # 含有上述範圍的C至Ν的元素，其餘部分係由Fe以 及雜質所組成，雜質中的Ca、Mg、Ti、Zr以及REM係 C a :未滿 0.0 0 1 %、M g :未滿 〇 · 0 〇 1 %、T i :未滿 0 _ 0 0 2 %、Any of Mg, Ti, Zr, and REM is preferably 0.0005% or less. As described above, "REM" is a general term for the total of 17 elements of S c, Y, and yttrium-like elements, and the content of rEm is Refers to the total content of the above elements. Concentration product of Μη and Ο(Μηχ〇): more than 0.018# contains elements of C to bismuth in the above range, and the rest consists of Fe and impurities. Ca, Mg, Ti, Zr and REM in the impurities are Ca: Less than 0.0 0 1 %, M g : not full 〇 · 0 〇 1 %, T i : less than 0 _ 0 0 2 %,

Zr:未滿0.002%以及rem:未滿0.001%的鋼，其中的 Μη與0的濃度積的値，也就是說，「Μηχ〇」的値若超過 0 · 0 1 8的情況下，即可確保在1 〇 〇 m/分鐘以下的較低速領 域下利用HSS工具進行切削時之所期望的優異的被切削性 〇 因此’ Mn與〇的濃度積也就是Μη X Ο的値必須超過 -23- (20) (20)1307720 0 · 0 1 8，換言之，必須符合前述（1)式。此外，上述（i)式「 Μ η X Ο」中的元素符號，係以該元素的質量％來表示在鋼中 的含量’ Μηχ〇的値的上限係0.030爲宜。Μη χ〇的値若超 過0 · 0 3 0的情況下’寬度較大的Μη系硫化物的分布密度 不會太高’有時候會難以獲得良好的拋光面粗糙度與切削 肩處理性。Zr: steel of less than 0.002% and rem: less than 0.001%, wherein 积 of 浓度η and 0 is 値, that is, if 値 χ〇 χ〇 超过 exceeds 0 · 0 1 8 Ensure the excellent machinability expected when cutting with HSS tools in the lower speed range below 1 〇〇m/min. Therefore, the concentration product of Mn and 〇 is Μη X Ο must exceed -23 - (20) (20) 1307720 0 · 0 1 8. In other words, it must conform to the above formula (1). Further, the element symbol in the above formula (i) "Μ η X Ο" is preferably expressed by the mass % of the element, and the upper limit of 値 0.0 χ〇 χ〇 is preferably 0.030. When Μη χ〇 exceeds 0 · 0 3 0, the distribution density of 宽度 系 sulfides with a large width is not too high. Sometimes it is difficult to obtain good polished surface roughness and shoulder handling properties.

Mn/(S + 0)：超過2.5但未滿3.5 含有上述範圍的C至N的元素，其餘部分係由Fe以 及雜質所組成，雜質中的Ca、Mg、Ti、Zr以及REM係 C a :未滿 0.0 〇 1 %、M g :未滿 0 · 〇 〇 1 %、τ i :未滿 0. Ο Ο 2 %、 Zr :未滿 0.002%以及REM :未滿 0.001%的鋼，其中的 Mn/(S + 0)的値係超過2.5的情況下，在凝固階段時可使得 作爲Μη系硫化物的生成核的Μη系氧化物大量地分散， 而可增加寬度大的Μη系硫化物的分布密度，所以可獲得 所期望之良好的被切削性。此外，Mn/(S + 0)的値爲2.5以 下的情況下，利用連續鑄造進行製造的話，鑄片内部會產 生裂隙等現象而導致熱間加工性的降低，但是Mn/(S + 0) 的値若超過2.5的話，不僅使合工業性規模的大量生産， 亦可確保充分的熱間加工性。 另一方面，Mn/(S + 0)的値爲3.5以上的情況下，相對 於所含有的S、0的量，Μη的含量會過剩’導致固熔在組 織中的Μη量變成過剩，因而被切削性’特別是工具壽命 會惡化。此外，在實質上並未含Al、Si、Ca、Mg、Ti' Zr以及REM的本發明中，爲了 Μη發揮作爲脫氧元素的 -24- (21) 1307720 作用’如果Μη含量過剩的話，就無法獲得：爲了得到可 改善被切削性的Μη系硫化物的形態之充分的〇量，所以 _ 切削屑處理性會降低，並且拋光面粗糙度會變大。 因此，Mn/(S + 〇)的値需要超過2.5且未滿3_5，換言 之，必須符合前述（2)式。此外，上述的（2)式「Mn/(S + 〇) 」中的元素符號是以該元素的質量％來表示在鋼中的含量 〇 • 基於上述的理由，本發明（1)的低碳含硫快削鋼的化學 組成係界定成含有：上述範圍的C至N的元素，其餘部分 係由Fe以及雜質所組成，雜質中的Ca、Mg、Ti、Zr以及 REM 係 Ca :未滿 0.001%、Mg :未滿 0.001%、Ti :未滿 0.002%、Zr:未滿 0.002%以及 REM:未滿 0.001%，且符 合前述的（1)式以及（2)式。 又，本發明（2)的低碳含硫快削鋼的化學組成’係針對 本發明（1)的低碳含硫快削鋼，將其中的N含量界定在N ® : 0.0060 〜0.0250%。 本發明的低碳含硫快削鋼，亦可因應必要’以從後述 的第1群所選出的種以上的元素以及從第2群所選出的1 種以上的元素之其中一方或雙方，當作可隨意添加的元素 來添加含有，以取代Fe的一部分。 以下，將說明上述第1群以及第2群的可隨意添加的 元素。 第 1 群：Te: 0.0005 〜0.03%、Sn: 0.001 % 以上且未 滿0.5 0 %以及S e : 0.0 〇 〇 5 %以上且未滿〇 · 3 〇 % -25- (22) (22)1307720 T e、S η以及S e均不會損及可改善被切削性的中介物 的較佳形態，而具有提高被切削性的作用。因此’在 100m/分鐘以下的較低速領域內使用HSS工具的時候’如 果想要獲得更優異的被切削性的話，亦可在以下的範圍內 來予以含有。Mn/(S + 0): an element of C to N containing more than 2.5 but less than 3.5 in the above range, the remainder consisting of Fe and impurities, and Ca, Mg, Ti, Zr and REM in the impurity are Ca: Less than 0.0 〇1 %, M g : less than 0 · 〇〇1 %, τ i : less than 0. Ο Ο 2 %, Zr: less than 0.002% and REM: less than 0.001% steel, of which Mn When the lanthanoid system of /(S + 0) exceeds 2.5, the Μ-type oxide which is a nucleus of the Μ-based sulfide can be largely dispersed in the solidification stage, and the distribution of the Μ-type sulfide having a large width can be increased. The density is such that the desired good machinability can be obtained. In addition, when the enthalpy of Mn/(S + 0) is 2.5 or less, when it is produced by continuous casting, cracks or the like are formed inside the cast piece, and the inter-heat workability is lowered, but Mn/(S + 0) If it exceeds 2.5, it will not only enable mass production on an industrial scale, but also ensure sufficient hot workability. On the other hand, when the enthalpy of Mn/(S + 0) is 3.5 or more, the content of Μη is excessive with respect to the amount of S and 0 contained, and the amount of Μη which solid-melt in the structure becomes excessive, and thus Machinability 'especially tool life will deteriorate. Further, in the present invention which does not substantially contain Al, Si, Ca, Mg, Ti'Zr, and REM, the role of -24-(21) 1307720 as a deoxidizing element is exhibited for Μ η if the Μη content is excessive, Obtained: In order to obtain a sufficient amount of Μ 系 sulfide which can improve the machinability, _ chip handling property is lowered, and the polishing surface roughness is increased. Therefore, the enthalpy of Mn/(S + 〇) needs to exceed 2.5 and not more than 3_5, in other words, it must conform to the above formula (2). Further, the element symbol in the above formula (2) "Mn/(S + 〇)" is a content expressed in steel in terms of the mass % of the element. 低 For the above reasons, the low carbon of the invention (1) The chemical composition of sulfur-containing fast-cut steel is defined as containing C to N elements in the above range, and the rest is composed of Fe and impurities. Ca, Mg, Ti, Zr and REM in the impurities Ca: less than 0.001 %, Mg: less than 0.001%, Ti: less than 0.002%, Zr: less than 0.002%, and REM: less than 0.001%, and conform to the above formulas (1) and (2). Further, the chemical composition of the low-carbon sulfur-containing quick-cut steel of the invention (2) is directed to the low-carbon sulfur-containing quick-cut steel of the invention (1), and the N content thereof is defined as N ® : 0.0060 to 0.0250%. The low-carbon sulfur-containing quick-cut steel of the present invention may be used as one or both of the elements selected from the first group described later and one or more elements selected from the second group. Add an element that can be added as desired to replace a part of Fe. Hereinafter, the elements of the first group and the second group which are freely addable will be described. Group 1: Te: 0.0005 to 0.03%, Sn: 0.001% or more and less than 0.50%, and S e : 0.0 〇〇 5% or more and less than 〇 · 3 〇% -25- (22) (22) 1307720 Each of T e, S η and S e does not impair the preferable form of the medium which can improve the machinability, but has an effect of improving the machinability. Therefore, when the HSS tool is used in a lower speed range of 100 m/min or less, if it is desired to obtain more excellent machinability, it can be contained in the following range.

Te: 0.0005 〜0.03%Te: 0.0005 to 0.03%

Te係可與Μη —起產生Mn(S、Te)，這個Mn(S、Te) 在切削過程中係可發揮擬似性的潤滑効果的功能。而且即 使添加了 Te，也只是增加了大粒度的Μη系硫化物的比例 而已，對於氧化物的形態並無影響，所以可提高在前述的 切削速度領域內使用HSS工具進行切削時的被切削性。但 是，如果其含量未滿0.0005 %的話，即使添加了該元素’ 効果也不明顯。另一方面，如果含Te超過了 0.03%，其 効果趨於飽和只會增加成本並無特別助益，而且熱間加工 性也會惡化。因此，如果想要添加的話，係將Te的含量 界定在0.0005〜0.03%。此外，爲了更穩定地兼具有良好 的熱間加工性與良好的被切削性，Te的含量係設定在 0.003〜0.02%爲宜，更好是設定在0.003〜0.01%。 S η : 0.0 0 1 %以上且未滿0.5 0 % S η係具有可改善鋼的被切削性的作用。這是因爲被 認爲Sn具有將基底金屬脆化的効果。但是，如果其含量 未滿0.0 0 1 %的話，添加的効果並不明顯。另一方面，如 果含Sn量是0.50%以的話，其効果將會飽和，而且熱間 加工性也會惡化。因此，如果想要添加的話，係將Sn的 -26- (23) 1307720 含量設定在0.001%以上且未滿0.50%。此外，爲了要兼具 有良好的熱間加工性與良好的被切削性，s η的含量是設 定在0.0 3 %以上0.3 0 %以下爲宜。 S e : 0.0 0 0 5 %以上且未滿0.3 0 %The Te system can produce Mn(S, Te) together with Μη, and this Mn(S, Te) can function as a pseudo-lubricating effect during the cutting process. Further, even if Te is added, the ratio of the Μη-based sulfide having a large particle size is increased, and the form of the oxide is not affected. Therefore, the machinability when cutting using the HSS tool in the above-described cutting speed can be improved. . However, if the content is less than 0.0005 %, the effect is not obvious even if the element is added. On the other hand, if the Te content exceeds 0.03%, the effect tends to be saturated, which only increases the cost, and the heat interworkability is also deteriorated. Therefore, if it is desired to add, the content of Te is defined to be 0.0005 to 0.03%. Further, in order to have both a good inter-heat processability and a good machinability, the content of Te is preferably 0.003 to 0.02%, more preferably 0.003 to 0.01%. S η : 0.0 0 1 % or more and less than 0.5 0 % S η has an effect of improving the machinability of steel. This is because it is considered that Sn has an effect of embrittlement of the base metal. However, if the content is less than 0.001%, the effect of the addition is not obvious. On the other hand, if the amount of Sn is 0.50%, the effect will be saturated, and the hot workability will be deteriorated. Therefore, if it is desired to add, the content of -26-(23) 1307720 of Sn is set to 0.001% or more and less than 0.50%. Further, in order to have both good hot workability and good machinability, the content of s η is preferably set to 0.03 % or more and 0.30% or less. S e : 0.0 0 0 5 % or more and less than 0.3 0 %

Se係可與Μη —起產生Mn(S、Se)，這種Mn(S、Se) 在進行切削過程中係可發揮擬似性的潤滑効果的功能。而 且即使添加了 S e，也只是增加了大粒度的Μη系硫化物的 比例而已，對於氧化物的形態並無影響，所以可提高在前 述的切削速度領域下使用HS S工具進行切削時的被切削性 。但是，如果其含量未滿0.0005 %的話，添加的効果並不 明顯。另一方面，即使含Se量是0.30%以上，其効果將 會趨於飽和而只是增加成本而且，而且熱間加工性也會惡 化。因此，如果想要添加的話，係將 Se的含量設定爲 0.0005 %以上且未滿0.30%。此外，爲了要更穩定地兼具 有良好的熱間加工性與良好的被切削性，係將Se的含量 設定在0.005%以上且0.1 5%以下爲宜。 上述的Te、Sn以及Se均可只添加其中任何1種而已 ，或者也可以將其中2種以上複合添加在一起。 第 2 群：Cu: 0.01 〜1.0 %、Ni: 0.01 〜1.0%、Cr: 0.0 1 〜1 . 0 % 以及 Μ 〇 : 0.0 1 〜0 _ 5 %The Se system can generate Mn (S, Se) together with Μη, and this Mn (S, Se) can function as a pseudo-lubricating effect during the cutting process. Further, even if S e is added, the ratio of the Μη sulfide to a large particle size is increased, and there is no influence on the form of the oxide. Therefore, it is possible to improve the use of the HS S tool for cutting in the above-described cutting speed field. Machinability. However, if the content is less than 0.0005%, the effect of the addition is not obvious. On the other hand, even if the amount of Se contained is 0.30% or more, the effect tends to be saturated, but the cost is increased, and the hot workability is deteriorated. Therefore, if it is desired to add, the content of Se is set to 0.0005% or more and less than 0.30%. Further, in order to have a good heat interfacial workability and good machinability, it is preferable to set the content of Se to 0.005% or more and 0.15% or less. Any one of the above-mentioned Te, Sn, and Se may be added, or two or more of them may be added together. Group 2: Cu: 0.01 to 1.0%, Ni: 0.01 to 1.0%, Cr: 0.0 1 to 1. 0 % and Μ 〇 : 0.0 1 to 0 _ 5 %

Cu、Ni、Cr以及Mo均具有提高鋼的強度的作用。因 此，如果想要提高製品強度的話，可在於以下的範圍內予 以含有。 C u : 〇 . 〇 1 〜1.0 % -27- (24) 1307720Cu, Ni, Cr, and Mo all have an effect of increasing the strength of the steel. Therefore, if it is desired to increase the strength of the product, it may be contained in the following range. C u : 〇 . 〇 1 ～1.0 % -27- (24) 1307720

Cu係可因爲晶析強化效果而具有提高鋼的強度的作 用。然而，其含量如果未滿0. 〇 1 %的話，其添加的効果並 不明顯。另一方面，如果Cu的含量超過1 .0 %的話，將導 致熱間加工性的惡化，而且Cu的晶析物會粗大化，所以 不僅前述的効果趨於飽和，也會導致被切削性的降低。因 此，如果想要添加的話，係將Cu的含量設定爲0.0 1〜 1.0%。此外，爲了’要穩定地兼具有良好的強度與良好的熱 間加工性，係將Cu的含量設定爲0.03〜0.50%爲宜，爲了 穩定地兼具有更爲良好的強度與良好的熱間加工性，係將 Cu的含量設定在0.05〜0.50 %更佳。 N i : 0.0 1 〜1 . 0 %The Cu system has a function of increasing the strength of the steel because of the crystallization strengthening effect. However, if the content is less than 0. 〇 1%, the effect of the addition is not obvious. On the other hand, if the content of Cu exceeds 1.0%, the inter-heat processability is deteriorated, and the crystallization of Cu is coarsened. Therefore, not only the aforementioned effects tend to be saturated, but also machinability is caused. reduce. Therefore, if it is desired to add, the content of Cu is set to 0.01 to 1.0%. Further, in order to "stablely have good strength and good hot-processability, it is preferable to set the content of Cu to 0.03 to 0.50%, in order to stably have both better strength and good heat. The inter-processability is preferably set to a content of Cu of 0.05 to 0.50%. N i : 0.0 1 〜1 . 0 %

Ni係可利用固熔強化效果而具有提高鋼的強度之作用 。但是，如果其含量未滿0.01%的話，其添加的効果並不 明顯。另一方面，如果Ni的含量超過1.0%的話，不僅會 導致被切削性的惡化，也會使得熱間加工性惡化》因此， 如果想要添加的話，係將Ni的含量設定爲0.01〜1.0%。 此外，爲了要穩定地兼具有良好的強度、被切削性以及熱 間加工性，係將Ni的含量設定在0.03〜0.50%爲宜。The Ni system can enhance the strength of steel by utilizing the solid solution strengthening effect. However, if the content is less than 0.01%, the effect of the addition is not obvious. On the other hand, if the content of Ni exceeds 1.0%, not only the machinability is deteriorated, but also the inter-heat processability is deteriorated. Therefore, if it is desired to add, the Ni content is set to 0.01 to 1.0%. . Further, in order to stably have both good strength, machinability, and hot workability, it is preferable to set the content of Ni to 0.03 to 0.50%.

Cr : 0.01 〜1 .〇%Cr : 0.01 〜1 .〇%

Cr係具有提高鋼的強度之作用。Cr也具有提高鋼的 淬火性進而改善滲碳性的作用。但是，如果其含量未滿 0 · 0 1 %的話，其添加的効果並不明顯。另一方面，即使含 有Cr超過1 . 0%，前述的効果將會趨於飽和而不僅會增加 成本，還會降低被切削性。因此，如果想要添加的話，係 -28- (25) 1307720 將C r的含量設定爲〇 · 〇 1〜1 0 %。此外，爲了要穩定地兼 具有良好的強度、淬火性以及被切削性，係將Cr的含量 設定在〇 · 〇 2〜0 · 5 °/〇爲宜’爲了要穩定地具備更加良好的強 度、淬火性以及被切削性，係將C r的含量設定在〇. 〇 3〜 0.5 %更佳。 Μ 〇 : 0 · 〇 1 〜〇 _ 5 %The Cr system has an effect of increasing the strength of the steel. Cr also has an effect of improving the hardenability of steel and improving carburization. However, if the content is less than 0 · 0 1 %, the effect of the addition is not obvious. On the other hand, even if Cr is contained in excess of 1.0%, the aforementioned effects tend to be saturated, which not only increases the cost but also reduces the machinability. Therefore, if you want to add it, -28-(25) 1307720 sets the content of Cr to 〇 · 〇 1~1 0 %. In addition, in order to stably have both good strength, hardenability, and machinability, it is preferable to set the Cr content to 〇· 〇2 to 0 · 5 ° / ' in order to stably provide better strength. The quenching property and the machinability are preferably set to 〇3 to 0.5%. Μ 〇 : 0 · 〇 1 〇 _ _ 5 %

Mo係具有提高鋼的強度之作用。Mo也具有可提高鋼 的淬火性進而改善滲碳性的作用以及將組織細微化以提高 韌性的作用。然而，其含量如果未滿0 · 01 %的話，其添加 的効果並不明顯。另一方面，即使含有Μ 〇超過了 〇 . 5 %， BU述的効果將趨於飽和’不僅將使得成本增加，也會降低 被切削性。因此，如果想要添加的話，係將Μ 〇的含量設 定爲0 · 0 1〜0.5 %。此外，爲了要使其穩定地具備良好的強 度、淬火性、韌性以及被切削性，Mo的含量係設定在 0.05〜0.5 %爲宜。又，爲了要既可壓低製造成本，又具備 有良好的強度、淬火性、韌性以及被切削性，係將Mo的 含量設定在0.02〜0.3 %爲宜。 上述的Cu、Ni、Cr以及Mo均可只添加其中任何1 種而已，或者也可以將其中2種以上複合添加在一起。 基於上述的理由，本發明（3)的低碳含硫快削鋼的化學 組成，係針對於本發明（1)或本發明（2)的低碳含硫快削鋼 ，係界定成含 Te: 0.0005〜0.03%、Sn: 0.001 %以上且未 滿0.50%以及Se: 0.0 005 %以上且未滿0.30%之中的1種 以上’來取代Fe的一部分。 -29- (26) 1307720 又，本發明（4)的低碳含硫快削鋼的化學組成，係針對 於本發明（1)至本發明（3 )的任何一種低碳含硫快削鋼，係 界定成含 Cu: 0.01 〜1.0%、Ni: 0.01 〜1.〇%、Cr: 〇.〇1 〜 1 . 〇 %以及Mo : 0 · 0 1〜0 · 5 %之中的1種以上’來取代F e的 一部分。 此外，Μη系硫化物的分散形態、氧化物組成，有時 候係受到凝固速度、製造條件的左右。因此，本發明的低 碳含硫快削鋼，例如：係可採用下列的製法來進行工業規 模的大量生産。 首先，利用連續鑄造法來製造本發明的低碳含硫快削 鋼的情況下，必須先調整從轉爐之類的煉鋼爐倒至澆桶時 的出鋼階段以及在澆桶時的爐渣精煉階段時的狀態。 具體而言，在澆桶精煉開始時，先將熔鋼中所含有的 Μη量調整爲未滿1 .5%，較好是未滿1 .2%。在這個階段， 即使令熔鋼中含有1 . 5 %以上的Μη，最終還是可以調整成 前述的範圍内，但是爲了要獲得適切的氧化物以及Μη系 硫化物的形態，最好是在精煉開始時的Μη的含量預先調 整成上述的含量。在進行這種Μη含量的調整之同時，就 將精煉開始時的爐渣中的ΜηΟ的含量調整到適切的範圍 ’具體而言，調整到2 5〜4 0 %的範圍更佳。然後，從精煉 的後半到末期，只要藉由添加入合金鐵來調整成預定的 Μη含量即可。 其次’爲了要獲得適切的Μη系硫化物的形態，而調 整鑄造時的冷却速度。 -30- (27) 1307720 亦即’鑄片的冷却速度，在於表皮以及中心部係有很 大的差’所以爲了要讓粒度大且最短平均粒子間距離很小 的Μη系硫化物以較大的分布密度穩定地存在，乃將中心 部的冷却速度設定爲至少1°C/分以上，更好是設定爲2。(：/ 分以上來進行冷却。 此外，在利用造塊法來製造鋼塊的時候，在鑄造小型 鋼錠的這種冷却速度很快的情況下，只要將鑄模設計成可 讓鋼塊中心部的冷却速度達到20T： /分以下的程度即可。 相反地，在鑄造巨大的鋼錠的這種冷却速度很慢的情況下 ’只要將鑄模設計成可使得中心部的冷却速度達到11 /分 以上的程度即可。 以下將利用實施例更加詳細說明本發明。 〔實施例〕 使用高周波電磁感應爐，將具有表1〜3所示的化學 組成的鋼1〜5 7加以熔製，以製作成直徑約2 2 0 m m的1 5 0 〜180kg的鋼塊。 表1中的鋼1〜23係化學組成分爲本發明所界定的範 圍内的鋼（以下’稱爲「本發明例的鋼」）。另一方面，表 2中的鋼24〜41以及表3中的鋼42〜57係化學組成分脫 離本發明所界定的比較例的鋼。此外，比較例的鋼之中的 鋼5 5〜5 7係相當於以往的含p b快削鋼的鋼。 上述的各種鋼之中’本發明例的鋼也就是鋼1〜23及 比較例的鋼之中的鋼29、鋼30、鋼34、鋼36以及鋼50 -31 - (28) 1307720 〜5 7 ’都是控制了其在熔製階段時的溶氧量以及凝固速度 而製作成鋼塊。換言之’原料鐵熔融之後，在添加過副原 料的階段，係在熔鋼内添加入以鐵箔包裹的狀態來販售的 MnO粉末’然後，實施成分的調整，以MOiTC前後的温度 出鋼倒入鑄模。此外，爲了調節鋼的凝固速度，先出鋼導 入到以砂子圍繞起來的陶瓷製的坩鍋以將凝固速度調整成 適切的速度。 φ 另一方面，比較例的鋼之中的鋼24〜28、鋼31〜33 、鋼3 5以及鋼3 7〜4 9，則並未講究上述這種特別的手段 就進行熔製。換言之，添加過副原料後，並未加入MnO 粉體，或者並未採用以砂子圍繞起來的陶瓷製的坩鍋，直 接鑄造到一般的鑲模。 -32- 1307720Mo has the effect of increasing the strength of steel. Mo also has an effect of improving the hardenability of steel and improving carburization, and miniaturizing the structure to improve the toughness. However, if the content is less than 0.01%, the effect of the addition is not obvious. On the other hand, even if the Μ 〇 exceeds 〇 5 %, the effect of the BU will tend to be saturated, which will not only increase the cost but also reduce the machinability. Therefore, if you want to add it, set the content of Μ 为 to 0 · 0 1~0.5 %. Further, in order to stably provide good strength, hardenability, toughness, and machinability, the content of Mo is preferably set to 0.05 to 0.5%. Further, in order to reduce the manufacturing cost and to have good strength, hardenability, toughness, and machinability, it is preferable to set the Mo content to 0.02 to 0.3%. Any one of Cu, Ni, Cr, and Mo described above may be added, or two or more of them may be added together. For the above reasons, the chemical composition of the low-carbon sulfur-containing quick-cut steel of the invention (3) is directed to the low-carbon sulfur-containing quick-cut steel of the invention (1) or the invention (2), which is defined as containing Te : 0.0005 to 0.03%, Sn: 0.001% or more and less than 0.50%, and one or more of Se: 0.0 005 % or more and less than 0.30% to replace a part of Fe. -29- (26) 1307720 Further, the chemical composition of the low carbon sulfur-containing quick-cut steel of the invention (4) is any low-carbon sulfur-containing quick-cut steel for the invention (1) to the invention (3) , is defined as containing Cu: 0.01 to 1.0%, Ni: 0.01 to 1. 〇%, Cr: 〇.〇1 to 1 . 〇% and Mo: 0 · 0 1~0 · 5 % of one or more 'To replace part of F e. Further, the dispersion form and the oxide composition of the Μ-based sulfide may be affected by the solidification rate and the production conditions. Therefore, the low-carbon sulfur-containing quick-cut steel of the present invention, for example, can be mass-produced in an industrial scale by the following method. First, in the case of manufacturing the low-carbon sulfur-containing quick-cut steel of the present invention by the continuous casting method, it is necessary to first adjust the tapping stage from the steelmaking furnace such as the converter to the pouring barrel and the slag refining at the time of pouring the barrel. The state at the stage. Specifically, at the start of the refining of the ladle, the amount of Μη contained in the molten steel is first adjusted to less than 1.5%, preferably less than 1.2%. At this stage, even if the molten steel contains more than 1.5% of Μη, it can be adjusted to the above range, but in order to obtain suitable oxides and Μ 硫化 sulfide forms, it is preferable to start at the refining. The content of Μη in time is adjusted to the above content in advance. While the Μη content is adjusted, the content of ΜηΟ in the slag at the start of refining is adjusted to an appropriate range. Specifically, it is more preferably adjusted to a range of 25 to 40%. Then, from the latter half to the end of the refining, it is only necessary to adjust the predetermined Μη content by adding the alloy iron. Next, in order to obtain a suitable form of the Μ-type sulfide, the cooling rate at the time of casting was adjusted. -30- (27) 1307720 That is, the cooling rate of the cast piece is due to the large difference between the skin and the center. Therefore, in order to make the particle size large and the shortest average particle-to-particle distance is small, the Μ-type sulfide is larger. The distribution density is stably present, and the cooling rate of the center portion is set to at least 1 ° C / min or more, and more preferably set to 2. (: / The above is used for cooling. In addition, when the steel block is manufactured by the agglomeration method, in the case where the cooling speed of the cast small steel ingot is fast, the mold is designed to be at the center of the steel block. The cooling rate can be as low as 20 T: / min. Conversely, in the case where the cooling rate of casting a large steel ingot is very slow, 'the mold is designed so that the cooling rate of the center portion is 11 / min or more. The present invention will be described in more detail below by way of examples. [Examples] Steels 1 to 5 7 having the chemical compositions shown in Tables 1 to 3 were melted using a high-frequency electromagnetic induction furnace to prepare a diameter. A steel block of 150 to 180 kg of about 2 2 mm. The steel composition of the steels 1 to 23 in Table 1 is classified into steel within the range defined by the present invention (hereinafter referred to as "steel of the present invention") On the other hand, the steels 24 to 41 in Table 2 and the steels 42 to 57 in Table 3 are chemically separated from the steel of the comparative example defined by the present invention. Further, the steel of the comparative example is 5 5 5 5 7 series is equivalent to the previous steel with pb fast cutting steel Among the above various steels, 'the steel of the present invention is the steels 29 to 23 of the steels 1 to 23 and the steel of the comparative example, the steel 30, the steel 34, the steel 36, and the steel 50 - 31 - (28) 1307720 to 5 7' is controlled by the amount of dissolved oxygen and the solidification rate in the melting stage to form a steel block. In other words, after the raw material iron is melted, the iron foil is added to the molten steel at the stage of adding the auxiliary raw material. In the state of the package, the MnO powder sold is sold. Then, the composition is adjusted, and the steel is poured into the mold at a temperature before and after the MOiTC. In addition, in order to adjust the solidification speed of the steel, the first steel is introduced into a ceramic made of sand. The crucible is used to adjust the solidification rate to a suitable speed. φ On the other hand, in the steel of the comparative example, the steel 24 to 28, the steel 31 to 33, the steel 3 5, and the steel 3 7 to 4 9, are not concerned about the above. This special means is melted. In other words, after the addition of the auxiliary raw material, the MnO powder is not added, or the ceramic crucible surrounded by the sand is not used, and it is directly cast into a general insert. - 1307720

τ—I«τ—I«

Mn/(S+0) 的値 2.79 2.78 2.94 3.20 2.91 3.21 2.61 2.83 3.36 2.51 3.47 3.45 3.23 3.36 3.28 2.99 3.18 3.08 2.70 2.80 2.71 2.74 2.80 ΜηχΟ 的値 0.027 0.023 0.025 0.021 0.019 0.021 0.023 0.023 0.020 0.021 0.029 0.029 0.029 0.020 ；0.030 0.020 0.021 0.022 0.022 0.020 0.025 0.022 0.020 化 學 組 成 分（質量％) 其餘部分：Fe以及雜質 其他 - i - -1 Cr:0.30 Μο.Ό.15 Cu;0.26 Ni:0.20 Te:0.008 Te:0.015 Sn:0.25 Se:0.042 ;Te:0.005，Cr:0.09 Te:0.010sMo:0.05 Te:0.015,Cu:0.29 Se:0.055,Ni:0.15 Te:0.007,Sn:0.25 Cu:0.20,Ni:0.15 Cr:0.25,Cu:0.20,Te:0.0008 REM 0.0001 0.0005 0.0004 0.0003 0.0003 0.0004 0.0004 0.0004 0.0001 0.0001 0.0003 0.0003 0.0004 0.0001 0.0004 0.0002 0.0004 0.0002 0.0002 0.0004 0.0002 0.0001 0.0005 N 0.0002 0.0001 0.0001 ! 0.0003 0.0004 0.0012 0.0003 0.0003 0.0003 0.0004 0.0002 0.0004 0.0001 0.0002 S 0.0003 j 0.0003 0.0007 0.0006 0.0002 0.0003 0.0003 0.0001 0.0004 0.0002 0.0002 0.0003 0.0012 0.0011 0.0003 0.0002 0.0004 0.0004 0.0001 0.0003 0.0005 0.0003 0.0004 0.0007 0.0003 0.0001 0.0006 0.0006 0.0003 0.0002 0.0002 0.0002 0,0002 0.0002 0.0001 0.0003 0.0003 0.0003 0.0002 0.0002 0.0001 0.0003 0.0002 0.0004 0.0002 0.0003 0.0003 0.0004 0.0002 0.0006 0.0002 0.0002 0.0003 0.0001 0.0001 cd U 0.0004 0.0002 0.0003 0.0003 ； 0.0001 0.0003 0.0003 0.0002 0.0004 0.0002 0.0002 0.0002 0.0002 0.0006 0.0002 0.0005 0.0004 0.0002 0.0002 0.0002 0.0001 0.0002 0.0002 〇 0.0188 0.0168 0.0152 0.0109 0.0125 0.0135 0.0200 0.0172 0.0137 0.0145 0.0190 0.0160 0.0168 0.0134 0.0195 0.0142 0.0139 0.0131 0.0147 0.0147 0.0167 0.0154 0.0141 0.0090 0.0105 0.0085 0.0095 0.0130 0.0082 0.0070 0.0102 0.0120 0.0102 0.0111 0.0098 0.0094 0.0084 0.0095 0.0139 0.0197 0.0115 0.0176 0.0100 0.0126 0.0115 0.0036 < 0·00】 0.001 0.002 0.001 0.002 0.002 0.001 0.001 0.002 0.001 0.002 0.002 0.002 0.001 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 00 0.50 0.48 0.55 0.58 0.50 0.46 0.42 0.46 0.41 0.56 0.41 0.46 '0.51 0.43 0.45 0.46 0.46 0.54 0.54 0.47 0.54 0.51 0.49 0.067 0.095 ： 0.087 ： 1 0.092 ! 0.065 0.072 0.120 0.072 0.081 0.075 0.093 0.074 0.078 0.085 0.077 0.054 0.139 0.083 0.034 0.053 0.070 0.062 0.079 1.45 1.38 1.66 1.89 1.49 1.52 1.15 1.35 1.49 1.44 1.49 1.64 1.70 :1.49 1 i 1.54 1.42 1.51 1.71 1.51 1.36 1.51 1.44 1.41 0.005 0.004 0.007 0.006 0.009 0.012 0.010 0.004 0.010 0.009 0.007 0.005 0.006 ；0.011 i 0,005 0.007 0.003 0.001 0.009 0.007 0.004 0.006 0.008 〇 0.08 0.10 0.09 0.12 0.18 0.06 0.07 0.08 0.07 0.10 0.09 0.07 0.09 0.10 0.08 0.10 0.12 0.09 0.08 0.08 0.08 0.09 0.08 匿 —rsm 寸二 -33- 1307720Mn/(S+0) 値2.79 2.78 2.94 3.20 2.91 3.21 2.61 2.83 3.36 2.51 3.47 3.45 3.23 3.36 3.28 2.99 3.18 3.08 2.70 2.80 2.71 2.74 2.80 80ηχΟ 値0.027 0.023 0.025 0.021 0.019 0.021 0.023 0.023 0.020 0.021 0.029 0.029 0.029 0.020 ; 0.030 0.020 0.021 0.022 0.022 0.020 0.025 0.022 0.020 Chemical composition (mass%) The rest: Fe and impurities Other - i - -1 Cr: 0.30 Μο.Ό.15 Cu; 0.26 Ni: 0.20 Te: 0.008 Te:0.015 Sn: 0.25 Se: 0.042; Te: 0.005, Cr: 0.09 Te: 0.010 sMo: 0.05 Te: 0.015, Cu: 0.29 Se: 0.055, Ni: 0.15 Te: 0.007, Sn: 0.25 Cu: 0.20, Ni: 0.15 Cr: 0.25, Cu: 0.20, Te: 0.0008 REM 0.0001 0.0005 0.0004 0.0003 0.0003 0.0004 0.0004 0.0004 0.0001 0.0001 0.0003 0.0003 0.0004 0.0001 0.0004 0.0002 0.0004 0.0002 0.0002 0.0004 0.0002 0.0001 0.0005 N 0.0002 0.0001 0.0001 ! 0.0003 0.0004 0.0012 0.0003 0.0003 0.0003 0.0004 0.0002 0.0004 0.0001 0.0002 S 0.0003 j 0.0003 0.0007 0.0006 0.0002 0.0003 0.0003 0.0001 0.0004 0.0002 0.0002 0.0003 0.0012 0.0011 0.0003 0.0002 0.0004 0.0004 0.0001 0.0003 0.0005 0.0003 0. 0004 0.0007 0.0003 0.0001 0.0006 0.0006 0.0003 0.0002 0.0002 0.0002 0,0002 0.0002 0.0001 0.0003 0.0003 0.0003 0.0002 0.0002 0.0001 0.0003 0.0002 0.0004 0.0002 0.0003 0.0003 0.0004 0.0002 0.0006 0.0002 0.0002 0.0003 0.0001 0.0001 cd U 0.0004 0.0002 0.0003 0.0003 ; 0.0001 0.0003 0.0003 0.0002 0.0004 0.0002 0.0002 0.0002 0.0002 0.0006 0.0002 0.0005 0.0004 0.0002 0.0002 0.0002 0.0001 0.0002 0.0002 〇0.0188 0.0168 0.0152 0.0109 0.0125 0.0135 0.0200 0.0172 0.0137 0.0145 0.0190 0.0160 0.0168 0.0134 0.0195 0.0142 0.0139 0.0131 0.0147 0.0147 0.0167 0.0154 0.0141 0.0090 0.0105 0.0085 0.0095 0.0130 0.0082 0.0070 0.0102 0.0120 0.0102 0.0111 0.0098 0.0094 0.0084 0.0139 0.0197 0.0115 0.0176 0.0100 0.0126 0.0115 0.0036 < 0·00] 0.001 0.002 0.001 0.002 0.002 0.001 0.001 0.002 0.001 0.002 0.002 0.002 0.001 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 00 0.50 0.48 0.55 0.58 0.50 0.46 0.42 0.46 0.41 0.56 0.41 0.46 ' 0.51 0.43 0.45 0.46 0.46 0.54 0.54 0.47 0.54 0.51 0.49 0.067 0.095 : 0.087 : 1 0.092 ! 0.065 0.072 0.120 0.072 0.081 0.075 0.093 0.074 0.078 0.085 0.077 0.054 0.139 0.083 0.034 0.053 0.070 0.062 0.079 1.45 1.38 1.66 1.89 1.49 1.52 1.15 1.35 1.49 1.44 1.49 1.64 1.70 :1.49 1 i 1.54 1.42 1.51 1.71 1.51 1.36 1.51 1.44 1.41 0.005 0.004 0.007 0.006 0.009 0.012 0.010 0.004 0.010 0.009 0.007 0.005 0.006 ;0.011 i 0,005 0.007 0.003 0.001 0.009 0.007 0.004 0.006 0.008 〇0.08 0.10 0.09 0.12 0.18 0.06 0.07 0.08 0.07 0.10 0.09 0.07 0.09 0.10 0.08 0.10 0.12 0.09 0.08 0.08 0.08 0.09 0.08 隐—rsm inch two-33- 1307720

««

Mn/(S+0) 的値 3.46 * 4.04 3.45 3.44 2.59 3.02 3.30 2.56 * 4.81 * 1.04 3.02 3.44 2.57 3.12 2.53 2.96 * 2.16 * 2.14 *記號表示脫離本發明所界定的條件。 ΜηχΟ 的値 *0.008 *0.005 0.021 0.024 0.028 0.021 0.020 *0.006 0.026 *0.010 0.024 *0.006 0.023 *0.013 *0.014 *0.016 0.028 0.019 化 學 組成分（質量％) 其餘部分：Fe以及雜質 其他 i · 1 1 1 1 1 1 ι 1 ι 1 1 1 ι 1 1 1 REM 0.0002 0.0004 0.0003 0.0004 0.0004 0.0003 0.0003 0.0004 0.0004 0.0002 0.0005 0.0002 0.0003 0.0005 0.0005 0.0005 0.0001 0.0003 N 0.0002 0.0003 0.0004 0.0005 0.0002 0.0002 0.0003 ; 0.0005 0.0001 0.0002 1 0.0002 0.0004 1 0.0004 0.0004 0.0002 0.0003 0.0002 0.0005 0.0002 0.0002 0.0001 0.0007 0.0007 0.0002 0.0002 0.0001 0.0003 0.0002 0.0004 0.0004 0.0004 0.0005 0.0003 0.0004 0.0005 0.0002 tj) s 0.0002 0.0004 0.0002 ; 0.0001 0.0001 丨 0.0005 0.0005 0.0001 0.0004 0.0002 0.0002 ί 0.0003 1 0.0005 0.0003 0.0003 0.0004 0.0004 0.0002 0.0002 0.0001 0.0003 0.0003 0.0004 0.0003 0.0001 0.0003 0.0003 0.0002 0.0005 i 0.0005 0.0002 0.0002 0.0003 0.0003 0.0002 0.0005 ο *0.0080 *0.0048 0.0168 0.0188 0.0148 0.0134 0.0120 *0.0042 0.0101 0.0182 0.0160 1 *0.0034 0.0187 0.0099 0.0134 0.0108 *0.0295 0.0162 0.0070 0.0061 0.0065 0.0086 0.0110 0.0110 0.0127 0.0085 0.0079 0.0085 0.0133 0.0098 *0.0020 0.0061 0.0064 0.0070 0.0115 0.0104 < 0.001 0.001 0.002 ι 1 0.001 ； 0.002 0.002 0.002 0.002 0.002 0.002 0.002 *0.015 ! 0.002 0.001 0.001 0.001 0.002 0.001 *0.29 *0.24 *0.34 *0.35 *0.72 0.51 0.50 0.52 0.52 0.51 0.49 0.52 0.46 0.42 0.41 0.50 0.41 0.53 &Η 0.032 0.026 : 0.061 0.058 0.049 0.072 0.075 0.096 0.087 0.041 *0.320 0.129 0.064 0.027 0.032 0.070 0.068 0.095 Μη _1 1.03 ! 0.99 ! 1.23 1.27 1.90 1.58 1.68 1.35 *2.55 *0.55 1.53 1.80 1.23 1.34 1.07 1.51 0.95 1.17 0.004 0.015 0.008 0.007 0.008 0.004 0.004 *0.250 0.009 0.004 0.004 0.007 0.003 0.006 0.004 0.005 0.009 0.009 υ 0.09 0.07 0.08 0.09 0.09 *0.04 *0.23 0.10 0.09 0.06 0.08 0.07 0.09 0.08 ；0.12 0.08 0.10 0.09 1 -34- 1307720Mn of Mn/(S+0) 3.46 * 4.04 3.45 3.44 2.59 3.02 3.30 2.56 * 4.81 * 1.04 3.02 3.44 2.57 3.12 2.53 2.96 * 2.16 * 2.14 *The mark indicates the condition defined by the present invention. ΜηχΟ 値*0.008 *0.005 0.021 0.024 0.028 0.021 0.020 *0.006 0.026 *0.010 0.024 *0.006 0.023 *0.013 *0.014 *0.016 0.028 0.019 Chemical composition (% by mass) The rest: Fe and impurities Other i · 1 1 1 1 1 1 ι 1 ι 1 1 1 ι 1 1 1 REM 0.0002 0.0004 0.0003 0.0004 0.0004 0.0003 0.0003 0.0004 0.0004 0.0002 0.0005 0.0002 0.0003 0.0005 0.0005 0.0005 0.0001 0.0003 N 0.0002 0.0003 0.0004 0.0005 0.0002 0.0002 0.0003 ; 0.0005 0.0001 0.0002 1 0.0002 0.0004 1 0.0004 0.0004 0.0002 0.0003 0.0002 0.0005 0.0002 0.0002 0.0001 0.0007 0.0007 0.0002 0.0002 0.0001 0.0003 0.0002 0.0004 0.0004 0.0004 0.0005 0.0003 0.0004 0.0005 0.0002 tj) s 0.0002 0.0004 0.0002 ; 0.0001 0.0001 丨0.0005 0.0005 0.0001 0.0004 0.0002 0.0002 ί 0.0003 1 0.0005 0.0003 0.0003 0.0004 0.0004 0.0002 0.0002 0.0001 0.0003 0.0003 0.0004 0.0003 0.0001 0.0003 0.0003 0.0002 0.0005 i 0.0005 0.0002 0.0002 0.0003 0.0003 0.0002 0.0005 ο *0.0080 *0.0048 0.0168 0.0188 0.0148 0.0134 0.0120 *0.0042 0.0101 0.0182 0.0160 1 *0.00 34 0.0187 0.0099 0.0134 0.0108 *0.0295 0.0162 0.0070 0.0061 0.0065 0.0086 0.0110 0.0110 0.0127 0.0085 0.0079 0.0085 0.0133 0.0098 *0.0020 0.0061 0.0064 0.0070 0.0115 0.0104 < 0.001 0.001 0.002 ι 1 0.001 ; 0.002 0.002 0.002 0.002 0.002 0.002 0.002 *0.015 ! 0.002 0.001 0.001 0.001 0.002 0.001 *0.29 *0.24 *0.34 *0.35 *0.72 0.51 0.50 0.52 0.52 0.51 0.49 0.52 0.46 0.42 0.41 0.50 0.41 0.53 & Η 0.032 0.026 : 0.061 0.058 0.049 0.072 0.075 0.096 0.087 0.041 *0.320 0.129 0.064 0.027 0.032 0.070 0.068 0.095 Μη _1 1.03 ! 0.99 ! 1.23 1.27 1.90 1.58 1.68 1.35 *2.55 *0.55 1.53 1.80 1.23 1.34 1.07 1.51 0.95 1.17 0.004 0.015 0.008 0.007 0.008 0.004 0.004 *0.250 0.009 0.004 0.004 0.007 0.003 0.006 0.004 0.004 0.006 0.004 0.005 0.005 0.005 0.07 0.08 0.09 0.09 *0.04 * 0.23 0.10 0.09 0.06 0.08 0.07 0.09 0.08 ;0.12 0.08 0.10 0.09 1 -34- 1307720

ε*ε*

Mn/(S+〇) 的値 * 4.86 * 1.84 2.99 3.43 3.33 3.12 3.20 2.91 3.49 2.98 3.44 2.85 3.16 * 4.05 3.47 3.04 O 擧 虼 鎞 I 鍵 ΜηχΟ 的値 0.020 *0,012 *0.017 *0.011 *0.014 *0.003 ；*0.003 ；*0.017 0.020 0.025 0.020 0.023 0.021 *0.015 *0,011 *0.016 化 學 組 成 分（質量％) 其餘部分：Fe以及雜質 其他 1 :. l*Cr:1.30 *M〇:0.70 +Te:0.058 *Sn:0_65 *Se:0.35 *Pb:0.25 *Pb:0.20 *Pb:0.31 REM 0.0002 0.0001 0.0002 0.0001 0.0003 0.0004 0.0006 *0.0013 0.0005 0.0004 0.0001 '0.0003 0.0002 0.0003 0.0004 0.0005 N 0.0002 0.0002 0.0003 j 0.0003 0.0003 0.0004 :*0.046 0.0002 0.0006 0.0004 0.0004 0.0003 0.0002 0.0005 0.0002 0.0003 0.0004 0.0002 0.0002 0.0004 0.0002 *0.054 0.0003 0.0001 0.0002 0.0005 0.0003 0.0001 0.0004 0.0003 0.0004 0.0003 0.0003 0.0004 0.0002 0.0001 *0.0015 0.0004 0.0002 I 0.0003 1 0.0003 0.0004 0.0002 0.0002 0.0005 0.0001 0.0004 0.0004 0.0002 0.0001 | 0.0003 *0.0020 0.0004 0.0003 0.0003 0.0001 0.0004 ；0.0002 0.0002 0.0002 0.0004 0.0003 0.0003 0.0002 〇 0.0098 0.0127 0.0122 i *0.0065 *0.0081 *0.0019 *0.0024 0.0107 0.0113 0.0163 ；0.0136 0.0154 0.0133 0.0112 *0.0085 0.0160 0.0086 0.0125 ! 0.0065 0.0087 0.0099 0.0065 ,0.0085 0.0083 0.0090 0.0102 0.0104 0.0127 0.0084 *0.0057 *0.0056 *0.0052 - 0.002 0.002 0.001 0.002 0.001 0.001 0.001 0.001 0.002 0.001 0.002 0.002 0.001 0.001 0.001 0.002 0.41 0.52 0.45 ； 0.47 0.51 0.47 0.42 1 i 0.53 1 0.47 0.49 0.42 0.50 0.48 *0.31 *0.32 *0.32 PU 0.078 0.077 0.033 0.075 0.058 0.034 0.045 0.038 0.060 0.049 0.055 '0.061 0.078 0.070 0.072 0.070 C S 2.04 0.98 | 1.38 j 1.65 1.73 1.47 1.35 1.56 1.68 1.51 1.49 1.47 1.56 1.30 1.14 1.02 0.011 0.008 ； 0.004 0.005 0.001 0.018 0.014 0.001 0.005 ；0.006 0.003 0.007 0.002 0.006 0.007 0.007 U 0.08 0.09 : 1 0.09 ： 0.07 0.10 0.09 0.07 0.08 0.09 0.07 0,07 0.08 0.09 0.10 0.10 0.07 m sfe * 靈 (Nm^r^〇v〇r^oo〇\〇 — -35- (32) 1307720 上述各種鋼的鋼塊，以靠近表面部之Di/8部（「Di」 是鋼塊的直徑）的位置作爲中心，從鋼塊高度方向採取直 徑1 0 m m、長度1 3 0 m m的高温拉伸試驗片，針對熱間加工 性加以調査。亦即，使用熱間加工再現試驗裝置，在大氣 壓中利用高周波加熱到達1 2 5 0 °C，並且保持5分鐘之後， 以l〇°C/分的速度冷卻到900°C，保持1〇秒鐘之後，以1〇 秒―1的變形速度在900°C的條件下進行高温拉伸試驗，調 査其熱間加工性。此外，上述棒狀試驗片的加熱區域係長 度方向的中央部約20mm，高温拉伸試驗後立即進行急速 冷卻。上述過程中，高温拉伸試驗的温度被選定爲90(TC 的理由是因爲一般而言，在低碳快削鋼的情況下，在 900 °C進行高温拉伸的縮徑値會變爲極小點。 熱間加工性係以上述高温拉伸試驗時的縮徑値（％)來 進行評估。此外，熱間加工性的目標，係採用：在上述高 温拉伸試驗時，具有4 0 %以上的縮徑値爲目標。此外，在 這種情況下，即使是含有超過0.4%的這種含有高S量的 鋼，在進行連續鑄造時，内部也不會產生裂隙，可穩定地 製造鑄片。 此外，根據以下所述的方法，針對各鋼的被切削性以 及滲碳性加以調査。 亦即，將各個鋼的上述直徑約220mm的鋼塊的其餘 部分，加熱到1 200 °C並保持2小時以上之後，以最後精製 温度保持在1 〇 〇 〇 °C以上的狀態進行熱間鍛造，鍛造後進行 空冷以製作成直徑40mm的圓棒。接下來，上述的各圓棒 -36- (33) 1307720 加熱到950°C並保持1小時間之後，進行空冷後，進行正 常化處理。此外，鋼3 3在進行熱間鍛造時就產生了裂隙 ，因此並未執行以下的調査。 接下來，將上述直徑40mm的圓棒的一部分予以切削 掉而製作成直徑3 1 mm的圓棒，對於這個圓棒實施冷間抽 拉加工，而精製成直徑爲28mm的圓棒。 以這種方式所製得的直徑爲28mm的圓棒係當作試驗 材，使用並未實施銨覆處理的HSS工具，具體而言，係使 用SKH4(JIS G 4403(2000))的旋削用車刀頭，根據下列的 條件進行旋削，以調查其被切削性。 •切削速度：l〇〇m/min; •給送量：〇.〇5mm/rev; •切入深度：0.5mm; •潤滑：使用水溶性潤滑油的濕式潤滑。 亦即，以上述條件進行1分鐘連續的旋削之後，使用 觸針式的粗糙度測定計，測定了最大高度的粗糙度Rz， 以針對抛光面粗糙度進行評估。 又’切削屑處理性係採取上述1分鐘所排出的切削屑 ’從最長的切削屑起依序採取2 0個切削屑，測定其質量 ’依據該質量來進行評估。這個質量的値愈小的話，可以 判定爲切削屑處理性愈良好。此外，針對於切削屑處理性 很差’因爲較長的切削屑被排出的結果，而無法獲得20 個的切削屑的試驗材，則是由其個數和質量來換算成每20 個的質量。 -37- (34) (34)1307720 此外，針對於工具磨損係以與上述相同的條件，進行 3 〇分鐘切削之後，測定的前端磨損量來進行評估。 上述的拋光面粗糙度、切削屑處理性以及工具磨損量 ，係分別以相當於以往的Pb快削鋼的鋼5 5〜5 7所具有的 各種特性之中最差者當作評估基準。亦即，抛光面粗糙度 係以鋼56的Rz也就是7.8μιη當作評估的基準値；工具磨 損量係以鋼57的175μιη當作評估的基準値，又，切削屑 處理性係以鋼55的切削屑質量2.7g當作評估的基準値。 而且拋光面粗糙度Rz爲 7.8 μιη以下、工具磨損量爲 1 75 μπι以下以及切削屑質量爲2.7g以下的情況下，就將 其當作具有與含Pb快削鋼同等以上的被切削性。 此外，從已經過正常化處理後的前述直徑40mm的各 圓棒的其餘部分，採取出直徑爲24mm，長度爲50mm的 円柱狀的試驗片來進行調查其滲碳性。 亦即，將上述直徑爲24mm且長度爲50mm的円柱狀 的試驗片，加熱到900°C以進行滲碳處理之後，在850°C的 溫度進行擴散處理，然後在80°C的油中進行冷却以實施淬 火處理。接下來，將上述試驗片加熱到190 °C並保持60分 鐘之後，進行空冷之後又實施回火處理。此外，上述滲碳 時的碳勢能値係0.8%且處理時間係75分鐘。又，進行擴 散時的碳勢能値係〇 . 7 %且處理時間係2 0分鐘。 從上述的滲碳淬火-回火處理後的試驗片的端部起迄 25mm爲止的位置，換言之，在試驗片的長度方向的中央 位置的横斷面，從表面起往内部，以2.94N的試驗力量來 -38- (35) (35)Mn of Mn/(S+〇)* 4.86 * 1.84 2.99 3.43 3.33 3.12 3.20 2.91 3.49 2.98 3.44 2.85 3.16 * 4.05 3.47 3.04 O 虼鎞I key ΜηχΟ 値0.020 *0,012 *0.017 *0.011 *0.014 *0.003 ;*0.003 ;*0.017 0.020 0.025 0.020 0.023 0.021 *0.015 *0,011 *0.016 Chemical composition (% by mass) Others: Fe and impurities Other 1 :. l*Cr: 1.30 *M〇: 0.70 +Te:0.058 *Sn:0_65 * Se: 0.35 * Pb: 0.25 * Pb: 0.20 * Pb: 0.31 REM 0.0002 0.0001 0.0002 0.0001 0.0003 0.0004 0.0006 * 0.0013 0.0005 0.0004 0.0001 '0.0003 0.0002 0.0003 0.0004 0.0005 N 0.0002 0.0002 0.0003 j 0.0003 0.0003 0.0004 :*0.046 0.0002 0.0006 0.0004 0.0004 0.0003 0.0002 0.0005 0.0002 0.0003 0.0004 0.0002 0.0002 0.0004 0.0002 *0.054 0.0003 0.0001 0.0002 0.0005 0.0003 0.0001 0.0004 0.0003 0.0004 0.0003 0.0003 0.0004 0.0002 0.0001 *0.0015 0.0004 0.0002 I 0.0003 1 0.0003 0.0004 0.0002 0.0002 0.0005 0.0001 0.0004 0.0004 0.0002 0.0001 | 0.0003 *0.0020 0.0004 0.0003 0.0003 0.0001 0.0004 ;0.0002 0.0002 0.0002 0.0004 0.0003 0.0003 0.0002 〇 0.0098 0.0127 0.0122 i *0.0065 *0.0081 *0.0019 *0.0024 0.0107 0.0113 0.0163 ;0.0136 0.0154 0.0133 0.0112 *0.0085 0.0160 0.0086 0.0125 ! 0.0065 0.0087 0.0099 0.0065 ,0.0085 0.0083 0.0090 0.0102 0.0104 0.0127 0.0084 *0.0057 *0.0056 *0.0052 - 0.002 0.002 0.001 0.002 0.001 0.001 0.001 0.001 0.002 0.001 0.002 0.002 0.001 0.001 0.001 0.002 0.41 0.52 0.45 ; 0.47 0.51 0.47 0.42 1 i 0.53 1 0.47 0.49 0.42 0.50 0.48 *0.31 *0.32 *0.32 PU 0.078 0.077 0.033 0.075 0.058 0.034 0.045 0.038 0.060 0.049 0.055 '0.061 0.078 0.070 0.072 0.070 CS 2.04 0.98 | 1.38 j 1.65 1.73 1.47 1.35 1.56 1.68 1.51 1.49 1.47 1.56 1.30 1.14 1.02 0.011 0.008 ; 0.004 0.005 0.001 0.018 0.014 0.001 0.005 ;0.006 0.003 0.007 0.002 0.006 0.007 0.007 U 0.08 0.09 : 1 0.09 : 0.07 0.10 0.09 0.07 0.08 0.09 0.07 0,07 0.08 0.09 0.10 0.10 0.07 m sfe * Ling (Nm^r^〇v〇r^oo〇\〇— -35- (32) 1307720 Steel blocks of the above various steels, close to the surface of the Di /8 part ("Di" is the diameter of the steel block) as the center, from the steel A high-temperature tensile test piece having a diameter of 10 mm and a length of 130 mm was used in the block height direction to investigate the hot workability. That is, using a hot-bed processing reproduction test apparatus, using high-frequency heating at atmospheric pressure to reach 1 250 ° C, and after 5 minutes, cooling to 900 ° C at a rate of 10 ° C / min, for 1 〇 second After the clock, a high-temperature tensile test was carried out at a deformation speed of 1 sec -1 at 900 ° C to investigate the hot workability. Further, the heating zone of the rod-shaped test piece was about 20 mm in the central portion in the longitudinal direction, and was rapidly cooled immediately after the high-temperature tensile test. In the above process, the temperature of the high temperature tensile test was selected to be 90 (the reason for TC is because, in general, in the case of low carbon fast-cut steel, the reduction enthalpy at high temperature stretching at 900 °C becomes extremely small. The heat interworkability is evaluated by the reduced diameter 値 (%) in the above high temperature tensile test. The hot workability is also achieved by using 40% or more in the above high temperature tensile test. In addition, in this case, even if it contains more than 0.4% of such a steel containing a high S amount, there is no crack inside during continuous casting, and the cast piece can be stably produced. In addition, the machinability and carburization of each steel were investigated according to the method described below. That is, the remaining portion of the steel piece having the above-mentioned diameter of about 220 mm of each steel was heated to 1,200 ° C and kept. After 2 hours or more, hot forging was carried out in a state where the final purification temperature was maintained at 1 〇〇〇 ° C or higher, and forging was carried out, followed by air cooling to prepare a round bar having a diameter of 40 mm. Next, each of the above-mentioned round bars -36- ( 33) 1307720 heated to 950 ° C After being kept for 1 hour, air cooling was performed, and normalization treatment was performed. Further, since the steel 3 3 was cracked during hot forging, the following investigation was not performed. Next, the above-mentioned 40 mm diameter round bar was used. A part of which was cut off to make a round rod with a diameter of 31 mm, and the rod was subjected to a cold drawing process to prepare a round rod having a diameter of 28 mm. A round rod having a diameter of 28 mm was produced in this manner. As a test material, the HSS tool that does not perform the ammonium coating treatment is used. Specifically, the turning head for turning using SKH4 (JIS G 4403 (2000)) is used to perform the turning according to the following conditions to investigate the Machinability • Cutting speed: l〇〇m/min; • Feeding amount: 〇.〇5mm/rev; • Cutting depth: 0.5mm; • Lubrication: Wet lubrication with water-soluble lubricating oil. After the above conditions were continuously rotated for 1 minute, the roughness Rz of the maximum height was measured using a stylus type roughness meter to evaluate the roughness of the polished surface. Exhausted chips 'From the longest cuttings, 20 chips are taken in order, and the mass is measured'. The quality is evaluated. If the mass is small, it can be judged that the chip processing property is better. In addition, for cutting The chip handling property is very poor. 'Because the long cutting chips are discharged, the test material that cannot obtain 20 chips is converted into the mass per 20 by its number and mass. -37- ( 34) (34) 1307720 In addition, for the tool wear, the measured front end wear amount was evaluated after 3 〇 minutes of cutting under the same conditions as above. The above-mentioned polished surface roughness, chip handling property, and tool wear were performed. The amount is the worst of the various characteristics of the steels corresponding to the conventional Pb quick-cut steels of 5 5 to 5 7 , respectively. That is, the roughness of the polished surface is based on the Rz of steel 56, which is 7.8 μm, as the reference 値; the tool wear amount is 175 μm of steel 57 as the reference 评估, and the chip handling is steel 55. The quality of the chips was 2.7 g as the basis for the evaluation. Further, when the polishing surface roughness Rz is 7.8 μηη or less, the tool wear amount is 1 75 μπι or less, and the chip quality is 2.7 g or less, it is considered to have the same machinability as the Pb-containing hot-cut steel. Further, from the remaining portion of each of the round bars having a diameter of 40 mm which had been subjected to the normalization treatment, a columnar test piece having a diameter of 24 mm and a length of 50 mm was taken to investigate the carburization property. That is, the above-mentioned columnar test piece having a diameter of 24 mm and a length of 50 mm was heated to 900 ° C for carburization treatment, then subjected to diffusion treatment at a temperature of 850 ° C, and then carried out in oil at 80 ° C. Cooling to carry out quenching treatment. Next, the test piece was heated to 190 ° C for 60 minutes, and then air-cooled and then tempered. Further, the carbon potential at the time of carburizing described above was 0.8% and the treatment time was 75 minutes. Further, the carbon potential energy at the time of diffusion was 〇 7 % and the treatment time was 20 minutes. The position from the end of the test piece after the carburization quenching-tempering treatment described above to 25 mm, in other words, the cross section at the center position in the longitudinal direction of the test piece, from the surface to the inside, was 2.94 N. Test strength comes to -38- (35) (35)

1307720 測定維氏硬度分布，從表面起至維氏硬度變成5 5 〇 位置當作「有効硬化層深度」，針對於滲碳性進行 此外，針對於滲碳性，也是以與以往的含Pb 相當的鋼5 5〜5 7的滲碳性之中最差者，當作評估 亦即，係以鋼5 7的有効硬化層深度〇 . 1 5mm當作評 準値。而以有効硬化層深度爲.0.15±0.05mm，換言 於有効硬化層深度爲0.10〜0.2 0mm的情況，當作 含P b快削鋼同等的滲碳性。 表4以及表5係彙整顯示出上述各試驗的結身 以及表5中的滲碳性欄的「◎」係表示有効硬化層 過0.20mm之具有優於含Pb快削鋼的滲碳性；「〇」 有効硬化層深度爲0.10〜0.20mm之具有與含Pb按 等的滲碳性；而「X」係表示有効硬化層深度少於 之具有劣於含Pb快削鋼的滲碳性。此外，表5中 的「-」係表示因爲無法進行熱間鍛造，所以並未罰 爲止的 評估。 快削鋼 基準。 :估的基 之，在 :具有與 !。表4 ί深度超 係表不 [削鋼同 0.10mm 的鋼3 3 I査。1307720 The Vickers hardness distribution is measured from the surface to the Vickers hardness of 5 5 〇 as the "effective hardened layer depth". For the carburization, the carburization is also equivalent to the conventional Pb-containing. The worst of the carburizing properties of steel 5 5 to 5 7 is evaluated as the effective hardened layer depth of steel 5 7 1 1 5 mm. The depth of the effective hardened layer is .0.15 ± 0.05 mm, in other words, the effective hardened layer depth is 0.10 to 0.2 0 mm, which is equivalent to the carburizing property of the P b-cut steel. Tables 4 and 5 show that the body of each of the above tests and the "◎" of the carburization column in Table 5 indicate that the effective hardened layer has a carburization property superior to that of the Pb-containing quick-cut steel when it passes through 0.20 mm; "〇" The effective hardened layer has a depth of 0.10 to 0.20 mm and has a carburizing property with Pb, and "X" indicates that the effective hardened layer has a depth lower than that of a Pb-containing hot-cut steel. In addition, the "-" in Table 5 indicates that the evaluation is not penalized because hot forging cannot be performed. Fast cutting steel benchmark. : The basis of the estimate, in: with and !. Table 4 ί depth super system is not [cut steel with 0.10mm steel 3 3 I check.

-39- (36)1307720 表 4-39- (36)1307720 Table 4

鋼 被切削性 滲碳性 熱間加工性 [縮徑率] (%) 精製面粗糙度 [RZ] (// m ) 切削屑 質量 (g) 工具前端 磨損量 (β m) 1 5.8 1.5 112 〇 52 2 5.5 1.6 104 〇 55 3 5.9 1.5 83 〇 59 4 6.1 1 . 1 74 〇 69 5 7.3 0.7 100 〇 66 6 6.8 1.6 88 〇 70 7 5.8 1.8 113 〇 5 7 8 5.2 1.4 105 ◎ 6 1 9 5.8 0.8 115 ◎ 72 10 6.4 0.9 110 〇 53 11 6.1 1 . 8 120 〇 69 1 2 5.5 2.1 118 〇 5 0 13 5 . 1 2.4 105 〇 46 14 5.6 2.3 116 〇 56 15 5.8 2.5 99 〇 45 16 6.1 2.6 113 ◎ 48 17 5.9 2.1 111 ◎ 46 18 5.5 2.0 103 〇 44 19 5.4 1.2 109 〇 42 20 5.6 2.6 105 〇 43 2 1 6.2 1 .2 112 〇 6 1 22 5.7 1 .8 113 ◎ 50 23 6.2 2.4 105 〇 59 *24 15.0 2.8 1 84 〇 59 *25 16.5 2.0 179 ◎ 72 *26 7.3 4.8 119 〇 65 *27 7.4 5.0 126 〇 68 *28 6.8 0.6 78 〇 19 *29 9.2 2.3 193 〇 69 * 3 0 8.0 1.0 222 〇 67 *記號表示脫離本發明所界定的條件。 滲碳性的欄中的「◎」、「〇」、「X」係表7K有效硬化 層深度分別是「超過〇.20mm」、「0.10〜0.20mm」、「 未滿0 . 1 0 m m」。 -40- (37)1307720 〔表5〕 表 5Steel machinability hot workability [reduction ratio] (%) Refined surface roughness [RZ] (// m ) Chip quality (g) Tool tip wear amount (β m) 1 5.8 1.5 112 〇 52 2 5.5 1.6 104 〇55 3 5.9 1.5 83 〇59 4 6.1 1 . 1 74 〇69 5 7.3 0.7 100 〇66 6 6.8 1.6 88 〇70 7 5.8 1.8 113 〇5 7 8 5.2 1.4 105 ◎ 6 1 9 5.8 0.8 115 ◎ 72 10 6.4 0.9 110 〇 53 11 6.1 1 . 8 120 〇 69 1 2 5.5 2.1 118 〇 5 0 13 5 . 1 2.4 105 〇 46 14 5.6 2.3 116 〇 56 15 5.8 2.5 99 〇 45 16 6.1 2.6 113 ◎ 48 17 5.9 2.1 111 ◎ 46 18 5.5 2.0 103 〇44 19 5.4 1.2 109 〇42 20 5.6 2.6 105 〇43 2 1 6.2 1 .2 112 〇6 1 22 5.7 1 .8 113 ◎ 50 23 6.2 2.4 105 〇59 * 24 15.0 2.8 1 84 〇59 *25 16.5 2.0 179 ◎ 72 *26 7.3 4.8 119 〇65 *27 7.4 5.0 126 〇68 *28 6.8 0.6 78 〇19 *29 9.2 2.3 193 〇69 * 3 0 8.0 1.0 222 〇67 * Marks indicate departure from the conditions defined by the present invention. "◎", "〇", and "X" in the carburizing column are 7K effective hardened layer depths of "more than 〇20mm", "0.10~0.20mm", and "less than 0.10 mm". . -40- (37) 1307720 [Table 5] Table 5

被切削性 熱間加工性 鋼 精製面粗糙度 切削屑 工具前端 滲碳性 [縮徑率] [R z ] 質量 磨損量 (%) (// m ) (g ) (// m ) * 3 1 15.8 0.9 116 〇 6 1 *32 8.4 0.8 152 ◎ 72 * 3 3 - - - - 5.2 *34 8.9 1.5 199 〇 42 *35 15.9 0.9 237 〇 5 9 *36 7.7 3.2 123 〇 48 *37 13.3 1.1 118 〇 6 1 *38 12.4 1.6 86 〇 5 3 *39 12.7 0.7 68 〇 57 *40 7.5 5.2 12 1 X 37 * 4 1 7.6 3.0 111 X 3 5 *42 9.5 2.5 157 ◎ 75 *43 9.3 3.4 128 X 30 *44 11.3 2.1 108 〇 58 *45 13.0 1.2 172 〇 59 *46 12.9 1 . 8 195 〇 64 *47 16.7 0.7 179 〇 5 8 *48 15.4 0.7 206 〇 5 8 *49 11.9 1.9 168 〇 5 8 *50 8.5 1 .7 275 ◎ 68 * 5 1 6.9 1.6 299 ◎ 64 * 52 4.8 2.9 107 〇 11 *53 5.4 2.5 13 7 〇 15 *54 6.7 2.3 118 〇 12 *55 5.8 # 2.7 117 〇 3 8 * 56 # 7.8 1.1 165 〇 39 * 57 4.1 1.8 # 175 〇 35 *記號表示脫離本發明所界定的條件。 被切削性的欄中的#記號表示基準値。 滲碳性的欄中的「 ◎」、厂 〇」、「x 」係表示有效硬化 層深度分別是「超過〇.20mm」、「0.1 0 〜0.20mm」、「 未滿 0 · 1 0mm j 〇 鋼3 3的^ 」係表示其無法進行熱間鍛造所以未進行調 查。 -41 - (38) 1307720 從表4以及表5可以明顯看出鋼1〜23之本發明的低 碳含硫快削鋼，即使並未含Pb ’依舊可獲得較長的工具 壽命、良好的切削屑處理性以及較小的拋光面粗糙度’並 且滲碳性亦優異。此外，其熱間加工性優於以往的含Pb 快削鋼，以工業方式的大量生産的情況下，並不會有任何 問題。 相對於此，脫離本發明所界定的條件的比較例的鋼， 在工具壽命、切削屑處理性、拋光面粗糙度、滲碳性以及 熱間加工性之中，至少有一個特性是較差的。 此外，針對於利用前述冷間抽拉加工而精製成直徑爲 28mm的各圓棒，從Df/4(「Df」係圓棒的直徑）的部位的 縱斷面方向切取出顯微觀察用試驗片，以進行Μη系硫化 物的調査。亦即，將前述試驗片埋入到樹脂內，進行鏡面 硏磨，並且使用導入了圖像解析軟體的自動圖像解析裝置 ，來測定被檢測面積5.2mm2的視野內所存在的Μη系硫 化物的寬度、最短平均粒子間距離以及分布密度。此外， 「最短平均粒子間距離」係指：從觀察到的個□ Μη系硫 化物的中心座標起位在最近距離處的Μη系硫化物的中心 座標間的距離，針對於各□ Μη系硫化物來求得，並且將 這些値予以平均化後的値。 其結果’鋼1〜23之本發明的低碳含硫快削鋼的情況 下’係可看出：寬度大且最短平均粒子間距離很小的Μη 系硫化物係以較大的分布密度存在，具體而言，寬度爲 4μιη以上且最短平均粒子間距離爲50μιη以下的Μη系硫 -42- (39) 1307720 化物係以、80個/mm2以上的較大分布密度存在。 以上雖然是依據實施例具體地說明了本發明，但是本 發明並不侷限在這些實施例。雖然並未以實施例來揭示， 但是只要是符合本發明的要件的話，當然也是被本發明所 包含。 〔産業上的可利用性〕 本發明的鋼雖然是未添加Pb的「善待地球環境的快 削鋼」，但是在100m/分鐘以下的較低速領域下使用HSS 工具進行切削時，係具有與以往的含Pb快削鋼以及添加 了 P b的複合快削鋼同等以上的良好的被切削性’換言之 ，具有較長的工具壽命、良好的切削屑處理性以及較小的 抛光面粗糙度，並且滲碳性優異’而且連續鑄造性優異’ 所以可低價地大量生産。因此’當作爲汽車用煞車零件、 電腦周邊機器零件以及電氣機器零件之類的軟質小零件的 素材來使用。 -43-Machinability of the surface roughness of the machinability of the machinability of the machinability of the machinability of the machinability of the cutting tool [R z ] 15.8 0.9 116 〇6 1 *32 8.4 0.8 152 ◎ 72 * 3 3 - - - - 5.2 *34 8.9 1.5 199 〇42 *35 15.9 0.9 237 〇5 9 *36 7.7 3.2 123 〇48 *37 13.3 1.1 118 〇6 1 *38 12.4 1.6 86 〇5 3 *39 12.7 0.7 68 〇57 *40 7.5 5.2 12 1 X 37 * 4 1 7.6 3.0 111 X 3 5 *42 9.5 2.5 157 ◎ 75 *43 9.3 3.4 128 X 30 *44 11.3 2.1 108 〇58 *45 13.0 1.2 172 〇59 *46 12.9 1 . 8 195 〇64 *47 16.7 0.7 179 〇5 8 *48 15.4 0.7 206 〇5 8 *49 11.9 1.9 168 〇5 8 *50 8.5 1 .7 275 ◎ 68 * 5 1 6.9 1.6 299 ◎ 64 * 52 4.8 2.9 107 〇 11 * 53 5.4 2.5 13 7 〇 15 * 54 6.7 2.3 118 〇 12 * 55 5.8 # 2.7 117 〇 3 8 * 56 # 7.8 1.1 165 〇 39 * 57 4.1 1.8 # 175 〇35 *The mark indicates the condition defined by the present invention. The # mark in the machinability column indicates the reference 値. "◎", "〇", and "x" in the column of carburization indicate that the effective hardened layer depths are "more than 〇20mm", "0.1 0 to 0.20mm", and "not more than 0 · 1 0mm j 〇" The "3" of the steel 3 indicates that it cannot be hot forged, so no investigation was conducted. -41 - (38) 1307720 It can be clearly seen from Table 4 and Table 5 that the low carbon sulfur-containing quick-cut steel of the present invention of steels 1 to 23 can still obtain a long tool life and good even without Pb'. The chip handling property and the small polished surface roughness' are also excellent in carburization. In addition, its hot inter-processability is superior to that of conventional Pb-containing hot-cut steel, and there is no problem in the case of mass production in an industrial manner. On the other hand, in the steel of the comparative example which deviates from the conditions defined by the present invention, at least one of the properties of the tool life, the chip handling property, the polishing surface roughness, the carburization property, and the heat interfacial property is inferior. Further, for each of the round bars having a diameter of 28 mm by the above-described cold drawing process, the microscopic observation test was taken out from the longitudinal direction of the portion of Df/4 (the diameter of the "Df" round bar). Tablets for the investigation of Μη sulfides. In other words, the test piece was embedded in a resin, mirror-honed, and an automatic image analysis device incorporating an image analysis software was used to measure the Μ-type sulfide present in the field of view having a detection area of 5.2 mm 2 . The width, the shortest average interparticle distance, and the distribution density. In addition, the "shortest average interparticle distance" refers to the distance between the center coordinates of the Μ 系 sulphide observed from the center coordinates of the Μ 系 sulfide at the closest distance, and the □ 系 vulcanization for each □ The object is to be obtained, and the cockroaches are averaged. As a result, in the case of the low carbon sulfur-containing quick-cut steel of the present invention of steels 1 to 23, it can be seen that the Μ 系 sulfide system having a large width and a shortest average interparticle distance is present at a large distribution density. Specifically, the Μη-sulfur-42-(39) 1307720 compound having a width of 4 μm or more and a shortest average interparticle distance of 50 μm or less is present at a large distribution density of 80 pieces/mm 2 or more. Although the invention has been specifically described above based on the embodiments, the invention is not limited to the embodiments. Although not disclosed by way of example, it is of course also encompassed by the present invention as long as it conforms to the requirements of the present invention. [Industrial Applicability] The steel of the present invention is a "clear steel for the global environment" in which Pb is not added, but when the HSS tool is used for cutting in a lower speed region of 100 m/min or less, The conventional machinability of Pb-free steel and P b-coated composite quick-cut steel is equal to or higher. In other words, it has a long tool life, good chip handling, and a small polished surface roughness. Moreover, it is excellent in carburization property and excellent in continuous casting property, so it can be mass-produced at low cost. Therefore, it is used as a material for soft parts such as automobile brake parts, computer peripheral machine parts, and electrical machine parts. -43-

Claims (1)

(1) 1307720 十、申請專利範圍 1.—種低碳含硫快削鋼，其特徵爲：以質量％換算， 係包含c : 0 · 0 5 %以上且未滿0 ·2 0 %、s i :未滿0 · 0 2 %、Μ η :0.7 〜2.2%、Ρ: 0.005 〜0.25%' S:超過 0.40% 且 0.60% 以下、A1:未滿 〇.〇〇3%、0: 0.0090 〜0.0280 %、N: 0.003 0〜0.0250°/。，其餘部分係由Fe以及雜質所組成，雜 質中的Ca、Mg、Ti、Zr以及REM係Ca:未滿0_001%、 Mg:未滿 〇·〇〇1%、Ti:未滿 0.002%、Zr:未滿 0.002%以 及REM :未滿0.001%，並且符合下列（1)式以及（2)式， Μηχ〇>0·018 · · (1)式； 2.5<Mn/(S + 0)<3 .5 …（2)式， 在（1)式以及（2)式中的元素符號係代表：以該元素的 質量％之在於鋼中的含量。 2 .如申請專利範圍第1項之低碳含硫快削鋼，其中的 N含量，以質量％換算，係N: 0.0060〜0.0250 %。 3.如申請專利範圍第1或2項之低碳含硫快削鋼，其 中係含 Te : 0.0005〜0.03%、Sn : 0.001%以上且未滿 0 · 5 0 %以及S e : 0 · 〇 〇 〇 5 %以上且未滿0.3 0 %之中的1種以上 ，來取代F e的一部分。 4 .如申請專利範圍第1至3項之任何一項所述之低碳 含硫快削鋼，其中係含C u : 0.0 1〜1 . 0 %、N i : 〇 1〜1. 〇 % 、Cr: 0.01〜1_〇%以及Mo: 0.01〜0.5 %之中的1種以上 ，來取代Fe的一部分。 -44 -(1) 1307720 X. Patent application scope 1. A low-carbon sulfur-containing quick-cutting steel characterized by: in terms of mass%, containing c: 0 · 0 5 % or more and less than 0 · 2 0 %, si : Less than 0 · 0 2 %, Μ η : 0.7 ～2.2%, Ρ: 0.005 ～0.25%' S: More than 0.40% and 0.60% or less, A1: Not full 〇.〇〇3%, 0: 0.0090 ～0.0280 %, N: 0.003 0~0.0250°/. The rest is composed of Fe and impurities. Ca, Mg, Ti, Zr and REM in the impurities Ca: less than 0_001%, Mg: less than 〇·〇〇1%, Ti: less than 0.002%, Zr : less than 0.002% and REM: less than 0.001%, and conforms to the following formulas (1) and (2), Μηχ〇>0·018 · · (1); 2.5<Mn/(S + 0) <3 .5 (2) Formula, the element symbol in the formulas (1) and (2) represents that the content by mass of the element is in the steel. 2. For the low-carbon sulfur-containing quick-cut steel of the first application of the patent scope, the N content, in terms of mass%, is N: 0.0060 to 0.0250%. 3. For low-carbon sulfur-containing quick-cut steel according to claim 1 or 2, which contains Te: 0.0005 to 0.03%, Sn: 0.001% or more and less than 0.55%, and S e : 0 · 〇 One or more of F 5 % or more and less than 0.3 0 % is substituted for a part of F e . 4. The low carbon sulfur-containing quick-cut steel according to any one of claims 1 to 3, wherein C u : 0.0 1~1 . 0 %, N i : 〇1~1. 〇% And Cr: 0.01 to 1_〇% and Mo: 0.01 to 0.5% of one or more of them, in place of a part of Fe. -44 -
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