JPH10287953A - Steel for machine structural use, excellent in mechanical property and drilling property - Google Patents
Steel for machine structural use, excellent in mechanical property and drilling propertyInfo
- Publication number
- JPH10287953A JPH10287953A JP9131543A JP13154397A JPH10287953A JP H10287953 A JPH10287953 A JP H10287953A JP 9131543 A JP9131543 A JP 9131543A JP 13154397 A JP13154397 A JP 13154397A JP H10287953 A JPH10287953 A JP H10287953A
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- steel
- cao
- oxide
- inclusions
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、機械的性質とドリル穴
あけ加工性に優れた機械構造用鋼に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel for machine structural use excellent in mechanical properties and drilling workability.
【０００２】[0002]
【従来の技術】従来、高い機械的性質を必要とする機械
構造部品などは、鍛造、圧延などの塑性加工で粗加工し
た後、切削加工によって所望の最終形状に仕上げるのが
一般的であった。2. Description of the Related Art Heretofore, it has been general that a mechanical structural part or the like requiring high mechanical properties is roughly processed by plastic working such as forging or rolling, and then finished to a desired final shape by cutting. .
【０００３】塑性加工後の切削加工を容易にする目的か
ら、被削性に優れた快削鋼に対する要求が近年ますます
増加してきている。In order to facilitate cutting after plastic working, demands for free-cutting steel having excellent machinability have been increasing more and more in recent years.
【０００４】その様な状況のもと、低速切削加工性に優
れた硫黄快削鋼や高速切削加工性に優れたカルシウム快
削鋼、ドリル穴あけ加工性に優れた硫黄、鉛快削鋼など
各種快削鋼が研究開発されており、切削加工条件に合わ
せた快削鋼が適宜使用されている。Under these circumstances, various types of free-cutting steel such as sulfur free-cutting steel excellent in low-speed cutting workability, calcium free-cutting steel excellent in high-speed cutting workability, sulfur and lead free-cutting steel excellent in drilling workability, etc. Free-cutting steel has been researched and developed, and free-cutting steel suitable for cutting conditions has been used as appropriate.
【０００５】しかしながら、一つの部品に適用される切
削加工は必ずしも一通りの加工ではなく、例えばドリル
穴あけ加工と高速切削加工の両方の加工が必要となる場
合は多い。この場合、両方の切削加工性を満足させるこ
とは非常に困難であった。[0005] However, the cutting applied to one part is not necessarily one type of processing. For example, it is often the case that both drilling and high-speed cutting are required. In this case, it was very difficult to satisfy both of the machinability.
【０００６】高速切削加工性に優れることで知られるＣ
ａを添加した快削鋼は、ＣａＯ−Ａｌ２Ｏ３−ＳｉＯ２
系の介在物によって被削性を向上させているため多量の
酸素を必要とし、鋼中に多量の酸化物が存在して、清浄
度に劣る場合が多く、機械的性質の制約から自ずと適用
範囲が限られていた。更にこうしたカルシウム快削鋼で
は、ドリル穴あけ加工性を向上させるような効果はなか
った。C, which is known for its excellent high-speed machinability
free cutting steels obtained by addition of a is, CaO-Al 2 O 3 -SiO 2
Since the machinability is improved by inclusions in the system, a large amount of oxygen is required, a large amount of oxides are present in the steel, and the cleanliness is often inferior. Was limited. Furthermore, such a calcium free-cutting steel had no effect of improving the drilling workability.
【０００７】清浄度向上のために酸素を低減させること
により酸化物を減少、微細化させる場合もあるが、この
場合はアルミナ主体の硬質酸化物が生成して工具に悪影
響を与え、被削性を低下させる。[0007] In some cases, oxides are reduced and refined by reducing oxygen to improve cleanliness. In this case, however, hard oxides mainly composed of alumina are formed and adversely affect the tool, resulting in poor machinability. Lower.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、上述した従
来の問題点に着目し、機械的性質に優れかつドリル穴あ
け加工性に優れた機械構造用鋼を提供することを目的と
する。SUMMARY OF THE INVENTION An object of the present invention is to provide a steel for machine structural use having excellent mechanical properties and excellent drilling workability, focusing on the above-mentioned conventional problems.
【０００９】[0009]
【課題を解決するための手段】本発明者は、種々の研究
を重ねた結果、低酸素硫黄快削鋼をベースにＣａを添加
する事によって、マンガン硫化物介在物の形状と組成、
アルミナ酸化物の組成、更にはそれらの析出形態をコン
トロールする事により下記（ａ）〜（ｃ）の知見を得る
に至った。Means for Solving the Problems The present inventor has conducted various studies and found that the addition of Ca based on low-oxygen sulfur free-cutting steel allows the shape and composition of manganese sulfide inclusions to be improved.
The following findings (a) to (c) have been obtained by controlling the composition of the alumina oxide and further the form of their precipitation.
【００１０】（ａ）Ａｌ：０．００２〜０．０５％かつ
Ｏ：０．０００５〜０．００３％の低酸素機械構造用鋼
に、Ｃａを添加する事によりマンガン硫化物介在物及び
従来のＣａＯ−Ａｌ２Ｏ３−ＳｉＯ２系介在物を有する
カルシウム快削鋼とは異なるアルミナ酸化物の双方に一
部Ｃａが含まれるようになる。(A) Manganese sulfide inclusions and conventional manganese sulfide inclusions are added to low oxygen mechanical structural steel containing 0.002 to 0.05% Al and 0.0005 to 0.003% O by adding Ca. It will include the Ca portion to both different alumina oxide and calcium free cutting steel having a CaO-Al 2 O 3 -SiO 2 inclusions.
【００１１】（ｂ）Ｃａを含有したマンガン硫化物介在
物（以下カルシウムマンガン硫化物という）はＣａを含
有しないマンガン硫化物介在物に比較して塑性変形能が
劣化するが故に鋳造後の圧延、鍛造時には比較的丸い紡
錘形状を維持する。(B) Ca-containing manganese sulfide inclusions (hereinafter referred to as calcium manganese sulfide) have a lower plastic deformability than manganese sulfide inclusions containing no Ca; During forging, a relatively round spindle shape is maintained.
【００１２】（ｃ）Ｃａを含有したアルミナ酸化物介在
物（以下カルシウムアルミネート酸化物という）は、ア
ルミナ主体の硬質酸化物に比較して軟化するとともに、
Ｃａを仲立ちとしてカルシウムマンガン硫化物との親和
性を増加させるため、硫化物よりも融点の高いカルシウ
ムアルミネート酸化物が先に析出した後、これを核とし
てカルシウムアルミネート酸化物を包み込むような形で
カルシウムマンガン硫化物が析出する。(C) Ca-containing alumina oxide inclusions (hereinafter referred to as calcium aluminate oxide) soften as compared to alumina-based hard oxides,
In order to increase the affinity with calcium manganese sulfide by using Ca as a mediator, a form in which calcium aluminate oxide having a melting point higher than that of sulfide is deposited first and then wrapped around calcium aluminate oxide using this as a nucleus. Causes precipitation of calcium manganese sulfide.
【００１３】上記知見に基づく本発明は、清浄度を確保
した低酸素鋼において、球状化した硫化物により機械的
性質の異方性を最小限に止めつつ、軟化した酸化物を更
に軟らかい硫化物で包み込む事により硬質酸化物と工具
の直接接触の回避して工具摩耗を低減してドリル穴あけ
加工性を向上させ、更にカルシウムアルミネート酸化物
による工具被覆効果で高速切削加工性をも向上させる機
械構造用鋼であり、下記（１）〜（２）の成分と介在物
形態を要旨とするものである。[0013] The present invention based on the above-mentioned knowledge is intended to provide a low-oxygen steel having a high degree of cleanliness, wherein the anisotropy of mechanical properties is minimized by spheroidized sulfide and the softened oxide is further softened to sulfide. A machine that avoids direct contact between the hard oxide and the tool by wrapping it with it, reduces tool wear and improves drilling workability, and also improves the high-speed cutting workability with the tool covering effect of calcium aluminate oxide. Structural steel having the following components (1) and (2) and inclusion forms.
【００１４】（１）重量％で、Ｃ：０．１０〜０．６０
％、Ｓｉ：０．５０％以下、Ｍｎ：０．３０〜１．５０
％、Ｓ：０．０１〜０．０７％、Ａｌ：０．００２〜
０．０５％、Ｃａ：０．０００５〜０．００５％、Ｏ：
０．０００５〜０．００３％を含有し、残部がＦｅ及び
不可避不純物からなり、かつＣａＯを８〜６２％含むカ
ルシウムアルミネート酸化物介在物を内部に包み込ん
だ、長径／短径比が５以下であるような紡錘型のＣａを
１％以上含むカルシウムマンガン硫化物介在物を含有す
ることを特徴とする機械的性質とドリル穴あけ加工性に
優れた機械構造用鋼。(1) In weight%, C: 0.10 to 0.60
%, Si: 0.50% or less, Mn: 0.30 to 1.50
%, S: 0.01 to 0.07%, Al: 0.002 to
0.05%, Ca: 0.0005 to 0.005%, O:
0.0005 to 0.003%, with the balance being Fe and inevitable impurities and enclosing calcium aluminate oxide inclusions containing 8 to 62% CaO, with a major axis / minor axis ratio of 5 or less A mechanical structure steel excellent in mechanical properties and drilling workability, characterized by containing a spindle-type calcium manganese sulfide inclusion containing 1% or more of Ca as described above.
【００１５】（２）上記（１）に記載の合金成分に加え
て更に重量％で、Ｐｂ：０．０４〜０．４％、Ｂｉ：
０．０２〜０．３％、Ｓｅ：０．１〜０．５％、Ｔｅ：
０．００３〜０．１％のうちの１種以上を含有し、残部
がＦｅ及び不可避不純物からなり、かつＣａＯを８〜６
２％含むカルシウムアルミネート酸化物介在物を内部に
包み込んだ、長径／短径比が５以下であるような紡錘型
のＣａを１％以上含むマンガン硫化物介在物を含有する
ことを特徴とする機械的性質とドリル穴あけ加工性に優
れた機械構造用鋼。(2) In addition to the alloy components described in the above (1), Pb: 0.04 to 0.4%, Bi:
0.02 to 0.3%, Se: 0.1 to 0.5%, Te:
One or more of 0.003 to 0.1%, the balance being Fe and unavoidable impurities, and CaO of 8 to 6%.
It contains manganese sulfide inclusions containing 1% or more of spindle-type Ca having a major axis / minor axis ratio of 5 or less, enclosing calcium aluminate oxide inclusions containing 2%. Machine structural steel with excellent mechanical properties and drilling workability.
【００１６】[0016]
【作用】以下に、本発明における鋼の化学組成及び介在
物形態を限定する理由について説明する。The reasons for limiting the chemical composition of steel and the form of inclusions in the present invention will be described below.
【００１７】Ｃ：Ｃは強度を確保するために必要な元素
であり、０．１０％未満では添加効果に乏しく、一方
０．６０％を越えると靭性が劣化するため、その含有量
を０．１０〜−０．６０％に限定する。C: C is an element necessary for securing the strength. If it is less than 0.10%, the effect of addition is poor, and if it exceeds 0.60%, the toughness deteriorates. Limited to 10-0.60%.
【００１８】Ｓｉ：Ｓｉは溶製時の脱酸剤として含有さ
れ、焼入れ性を向上させる元素である。しかし、０．５
０％を越えて多量に添加されると熱間加工時に割れを発
生しやすくなるため、０．５０％以下に限定する。Si: Si is an element contained as a deoxidizing agent at the time of smelting and improving the hardenability. However, 0.5
If added in a large amount exceeding 0%, cracks tend to occur during hot working, so the content is limited to 0.50% or less.
【００１９】Ｍｎ：Ｍｎは硫化物形成元素であり、０．
３０％未満では所望の効果が得られず、１．５０％を超
えると鋼の硬さを増大させて被削性を低下させるので、
その含有量を０．３０〜１．５０％に限定する。Mn: Mn is a sulfide forming element.
If it is less than 30%, the desired effect cannot be obtained, and if it exceeds 1.50%, the hardness of the steel is increased and the machinability is reduced.
Its content is limited to 0.30 to 1.50%.
【００２０】Ｓ：Ｓは被削性の向上に有効な元素であ
る。従って０．０１％未満では所望の効果が得られず、
０．０７％を超えると靭性と延性を悪化させるばかり
か、更にはＣａと高融点のＣａＳを形成して鋳造工程に
多大なる障害をもたらすため、その含有量を０．０１〜
０．０７％に限定する。尚好ましい範囲は０．０３％〜
０．０７％である。S: S is an element effective for improving machinability. Therefore, if less than 0.01%, the desired effect cannot be obtained,
If it exceeds 0.07%, not only does toughness and ductility deteriorate, but also Ca and CaS having a high melting point are formed, causing a great obstacle to the casting process.
Limited to 0.07%. A still more preferable range is 0.03% or more.
0.07%.
【００２１】Ａｌ：Ａｌは脱酸に必要な元素であり、
０．００２％以上必要とする。しかし、０．０５％を超
えると酸化物中のＡｌ量が過多となってのカルシウムア
ルミネート酸化物を形成する事が不可能となるため、そ
の含有量を０．００２〜０．０５％に限定する。Al: Al is an element necessary for deoxidation,
0.002% or more is required. However, if the content exceeds 0.05%, it becomes impossible to form a calcium aluminate oxide due to an excessive amount of Al in the oxide, so that the content is reduced to 0.002 to 0.05%. limit.
【００２２】Ｃａ：Ｃａは本発明においてきわめて重要
な意味を持つ元素である。即ち、マンガン硫化物介在物
の変形能を小さくして塑性加工後の硫化物形状を紡錘型
に維持するとともに、アルミナ酸化物を軟化させて工具
に与える衝撃を緩和し、更には酸化物を硫化物が包み込
むように仲立ちをする。以上の効果を達成するために
０．０００５％以上含有する事が必要である。しかし、
０．００５％を超えると高融点のＣａＳを形成して鋳造
工程に多大なる障害をもたらすため、その含有量を０．
０００５〜０．００５％に限定する。Ca: Ca is an element having a very important meaning in the present invention. That is, the deformability of the manganese sulfide inclusions is reduced to maintain the sulfide shape after plastic working in a spindle shape, while softening the alumina oxide to reduce the impact given to the tool, and further reducing the oxide sulfide. Mediate so that things wrap around. In order to achieve the above effects, it is necessary to contain 0.0005% or more. But,
If the content exceeds 0.005%, CaS having a high melting point is formed, causing a great obstacle to the casting process.
0005 to 0.005%.
【００２３】Ｏ：鋼中のＯは酸化物系介在物の形で存在
し、鋼の機械的性質に有害であり、極力低減させるのが
望ましい。Ａｌ０．００２〜０．０５％、Ｃａ０．００
０５〜０．００５％とした時低減可能なＯ量は０．００
０５％である。従来のＣａを含んだ快削鋼は主として、
ＣａＯ−Ａｌ２Ｏ３−ＳｉＯ２系の酸化物系介在物を鋼
中に生成させることにより、酸化物系の工具保護膜を形
成して被削性を向上させてきた。こうしたＣａＯ−Ａｌ
２Ｏ３−ＳｉＯ２系の酸化物介在物を生成させるには
０．００７好ましくは０．０１％以上のＯを必要として
いたため、鋼の清浄度と強度において劣る場合が多かっ
た。何故なら、Ｏは酸化物の生成エネルギーの観点か
ら、ＣａついでＡｌと結合する。従って、ＣａＯ−Ａｌ
２Ｏ３−ＳｉＯ２系の酸化物を生成させるためには、Ｃ
ａ及びＡｌと酸化物を形成する以上に多量のＯが必要で
あった。これに対して本発明では、カルシウムアルミネ
ート酸化物を形成する程度のＯ量で十分である。これに
伴って鋼の清浄度や強度が向上する。過剰なＯはかえっ
て鋼の強度を低下させるため、Ｏ量は０．００３％以下
としなければならない。以上の理由により、Ｏの含有量
を０．０００５％〜０．００３％に限定する。O: O in the steel is present in the form of oxide inclusions, which is harmful to the mechanical properties of the steel, and is desirably reduced as much as possible. Al 0.002 to 0.05%, Ca 0.00
When the content is set to 0.05 to 0.005%, the amount of O that can be reduced is 0.00.
05%. Conventional free-cutting steel containing Ca is mainly
By the CaO-Al 2 O 3 -SiO 2 based oxide inclusions is generated in the steel, has been to form a tool protective film of oxide to improve machinability. Such CaO-Al
Since O of 0.007, preferably 0.01% or more was required to generate 2 O 3 —SiO 2 -based oxide inclusions, the cleanliness and strength of steel were often poor. This is because O combines with Ca and then with Al from the viewpoint of oxide formation energy. Therefore, CaO-Al
In order to generate a 2 O 3 —SiO 2 -based oxide, C
A large amount of O was required to form an oxide with a and Al. On the other hand, in the present invention, an O amount sufficient to form a calcium aluminate oxide is sufficient. Accordingly, the cleanliness and strength of the steel are improved. Since excessive O lowers the strength of the steel instead, the O content must be 0.003% or less. For the above reasons, the content of O is limited to 0.0005% to 0.003%.
【００２４】本発明の機械的性質とドリル穴あけ加工性
に優れた機械構造用鋼には、上記成分に加えて更にＰ
ｂ，Ｂｉ，Ｓｅ，Ｔｅのうちの１種以上を含んでいても
よい。これらの合金元素の効果と含有量を限定する理由
について説明する。The steel for machine structural use according to the present invention, which has excellent mechanical properties and drilling workability, further comprises P in addition to the above components.
It may include one or more of b, Bi, Se, and Te. The effect of these alloy elements and the reason for limiting the content will be described.
【００２５】Ｐｂ、Ｂｉ：Ｐｂ、Ｂｉは単独で或いは硫
化物外周に付着する様な形で存在し、それ自身が被削性
を向上させる効果を有する。こうした効果を得るために
は、Ｐｂで０．０４％、Ｂｉで０．０２％以上が必要で
ある。過剰な場合にはＰｂ、Ｂｉの鋼への溶解度を超
え、かつその大きな比重のためにＰｂ，Ｂｉは単独で凝
集、沈殿して鋼中の欠陥となるため、含有量をＰｂで
０．０４％〜０．４％、Ｂｉで０．０２％〜０．３％に
限定する。Pb, Bi: Pb and Bi exist alone or in such a form as to adhere to the periphery of the sulfide, and have an effect of improving machinability by themselves. In order to obtain these effects, 0.04% for Pb and 0.02% or more for Bi are required. If it is excessive, the solubility of Pb and Bi in the steel is exceeded, and because of its large specific gravity, Pb and Bi agglomerate and precipitate singly to become defects in the steel. % To 0.4%, and Bi to 0.02% to 0.3%.
【００２６】Ｓｅ、Ｔｅ：Ｓｅ、Ｔｅも良く知られた被
削性を向上させる元素である。こうした効果を得るため
には、Ｓｅで０．１％、Ｔｅで０．００３％以上が必要
である。過剰な添加は熱間加工時に割れを発生しやすく
なるため、含有量をＳｅで０．１％〜０．５％、Ｔｅで
０．００３％〜０．１％に限定する。Se, Te: Se and Te are also well-known elements for improving machinability. In order to obtain such effects, 0.1% for Se and 0.003% or more for Te are required. Excessive addition tends to cause cracking during hot working, so the content is limited to 0.1% to 0.5% for Se and 0.003% to 0.1% for Te.
【００２７】介在物の形態：アルミナ主体の酸化物は非
常に硬質であり、工具と直接接触した場合には工具の摩
耗を促進する事が知られている。この酸化物にＣａＯを
含ませる事により酸化物自身を軟化させる事が可能であ
る。このためには少なくともアルミナ主体の酸化物をＣ
ａＯ−６Ａｌ２Ｏ３以上のＣａＯを含有した低融点酸化
物とする事が必要であり、ＣａＯの比率を８％以上にし
なければならない。逆に過剰なＣａＯも酸化物の硬質化
を引き起こすので３ＣａＯ−Ａｌ２Ｏ３以下のＣａＯ含
有量とする必要があり、ＣａＯの比率を６２％以下にし
なければならない。一方、通常のマンガン硫化物は鍛
造、圧延などの塑性加工に際して非常に良く展伸し、鋼
の機械的性質の異方性を助長する。展伸性を制限するた
めマンガン硫化物にＣａを１％以上含ませる事によりマ
ンガン硫化物の展伸性を減じる。また、正確に異方性を
評価する時、長径／短径比が５以下である様な紡錘形状
のマンガン硫化物を有する場合に鋼の機械的性質の異方
性は軽減される。更には相対的に硬質な酸化物を相対的
に軟質の硫化物が包み込む事により工具の摩耗は低減さ
れる。Form of inclusions: Alumina-based oxides are very hard, and are known to promote tool wear when they come into direct contact with the tool. By including CaO in this oxide, the oxide itself can be softened. For this purpose, at least an oxide mainly composed of alumina is converted to C
aO--6Al is necessary to the 2 O 3 or more low melting point oxide containing CaO, shall the ratio of CaO to at least 8%. Also excessive CaO reversed so cause hardening of the oxide must be a 3CaO-Al 2 O 3 less CaO content must the ratio of CaO below 62%. On the other hand, ordinary manganese sulfide expands very well during plastic working such as forging and rolling, and promotes anisotropy in mechanical properties of steel. The manganese sulfide is reduced in extensibility by adding 1% or more of Ca to the manganese sulfide to limit the extensibility. In addition, when accurately evaluating anisotropy, when a spindle-shaped manganese sulfide having a major axis / minor axis ratio of 5 or less is used, the anisotropy of mechanical properties of steel is reduced. Further, the relatively hard oxide wraps the relatively soft sulfide, thereby reducing tool wear.
【００２８】[0028]
【実施例】本発明鋼の特徴を実施例を用いて説明する。
表１及び表２に示す化学組成を有する鋼を５ｔｏｎアー
ク炉にて溶製した。表１中のＡ１からＡ９とａ１からａ
９はＪＩＳ規格のＳ４５Ｃに相当または類似した鋼であ
る。表１中のＢ１からＢ４とｂ１からｂ４はＪＩＳ規格
のＳ５５Ｃに相当または類似した鋼である。表１中のＣ
１からＣ３とｃ１からｃ４はＪＩＳ規格のＳＣＭ４１５
に相当した鋼である。表１中のＤ１からＤ７とｄ１から
ｄ２はＪＩＳ規格のＳＣＭ４４０に相当または類似した
鋼である。表２中のＡ６とＥ１からＥ５とｅ１からｅ４
はＪＩＳ規格のＳ４５Ｃに表中記載の各元素を添加した
鋼である。EXAMPLES The features of the steel of the present invention will be described with reference to examples.
Steels having the chemical compositions shown in Tables 1 and 2 were melted in a 5-ton arc furnace. A1 to A9 and a1 to a in Table 1
9 is a steel equivalent or similar to JIS standard S45C. B1 to B4 and b1 to b4 in Table 1 are steels corresponding or similar to S55C of JIS standard. C in Table 1
1 to C3 and c1 to c4 are JIS standard SCM415
It is steel corresponding to. D1 to D7 and d1 to d2 in Table 1 are steels corresponding or similar to SCM440 of JIS standard. A6 and E1 to E5 and e1 to e4 in Table 2
Is a steel obtained by adding each element described in the table to JIS standard S45C.
【００２９】圧延と鍛造により、断面が１１０ｍｍ×５
０ｍｍの角材を作製した。圧延と直角方向の機械的性質
を調査するために、引張試験と衝撃試験を実施した。引
張試験用として圧延と直角方向からＪＩＳ４号試験片を
作成し、試験はＪＩＳ Ｚ２２４１に従って実施した。
衝撃試験用として圧延と直角方向からＪＩＳ３号試験片
を作成し、ＪＩＳ Ｚ ２２４２に従って実施した。The cross section is 110 mm × 5 by rolling and forging.
A 0 mm square piece was produced. Tensile and impact tests were performed to investigate the mechanical properties in the direction perpendicular to the rolling. A JIS No. 4 test piece was prepared from a direction perpendicular to the rolling direction for a tensile test, and the test was performed in accordance with JIS Z2241.
A JIS No. 3 test piece was prepared from a direction perpendicular to the rolling direction for the impact test, and the test was performed in accordance with JIS Z2242.
【００３０】試験前処理として、各試験片に表３に示す
熱処理を実施した。As a test pretreatment, each test piece was subjected to a heat treatment shown in Table 3.
【００３１】圧延材の縦断面の検鏡試料を作成し、各試
料毎に最大長さ５μｍ以上の介在物２０個を任意に選び
出し、画像解析により介在物の最大径Ｌと最小径Ｗを測
定した。これより算出されるＬ／Ｗを表１、２中のＬ／
Ｗとした。A speculum specimen of a longitudinal section of a rolled material is prepared, and 20 inclusions having a maximum length of 5 μm or more are arbitrarily selected for each sample, and the maximum diameter L and the minimum diameter W of the inclusion are measured by image analysis. did. The L / W calculated from this is L / W in Tables 1 and 2.
W.
【００３２】前述の各試料毎２０個の介在物で、光学顕
微鏡を用いて観察した場合に黒色に見える内部の酸化物
相当部と薄灰色に見える周辺の硫化物相当部それぞれに
ついて、それらの組成をＥＰＭＡにて測定した。酸化物
の測定値の中で最大のＣａＯ比率（百分率）を示した値
を表１、２中のＣａＯ−Ｏとし、硫化物の測定値の中で
最大のＣａ比率（百分率）を示した値を表１、２中のＣ
ａ−Ｓとした。With the above-mentioned 20 inclusions for each sample, the composition of each of the internal oxide-corresponding portions that appear black when observed using an optical microscope and the peripheral sulfide-corresponding portions that appear light gray is shown. Was measured by EPMA. The value indicating the largest CaO ratio (percentage) among the measured values of the oxides is CaO-O in Tables 1 and 2, and the value indicating the largest Ca ratio (percentage) among the measured values of the sulfides In Tables 1 and 2
a-S.
【００３３】ドリル穴あけ加工性を評価するために、ハ
イスドリルを用いた寿命試験を実施した。切削条件を表
４に示す。ドリルの破損に至るまでの加工終了穴数をも
ってドリル寿命とした。In order to evaluate the drilling workability, a life test using a high speed drill was performed. Table 4 shows the cutting conditions. The drill life was defined as the number of processed holes up to the breakage of the drill.
【００３４】製造性として、鋳造性と圧延性を評価し
た。５ｔｏｎの溶鋼全量が２．５ｔｏｎインゴット２本
に鋳造完了しなかった場合を製造性劣とした。更に鋳造
完了した中でも、直径１００ｍｍの丸棒に圧延していく
工程において、１０％以上の外観疵による不良が発生し
た場合を製造性やや劣とし、２０％以上の外観疵による
不良が発生した場合を製造性劣とした。As the manufacturability, castability and rollability were evaluated. The case where the casting of the entire 5-ton molten steel was not completed in two 2.5-ton ingots was regarded as poor productivity. Further, even when casting is completed, in the process of rolling into a round bar having a diameter of 100 mm, the case where a defect due to an external flaw of 10% or more occurs is considered to be slightly poor in productivity, and the case where a defect due to an external flaw of 20% or more occurs. Was evaluated as poor in productivity.
【００３５】表２中の鋼については、圧延後の丸棒にて
発汗試験を実施し、異常の認められたものについては、
表６中に内部欠陥有りとした。For the steels in Table 2, a perspiration test was carried out using a round bar after rolling.
Table 6 shows that there was an internal defect.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 [Table 2]
【００３８】[0038]
【表３】 [Table 3]
【００３９】[0039]
【表４】 [Table 4]
【００４０】[0040]
【表５】 [Table 5]
【００４１】[0041]
【表６】 [Table 6]
【００４２】表１、表５よりＡの本発明鋼は少なくとも
ドリル寿命が１４以上である。これに対して、ａ１はＣ
成分が規定範囲を超えるため硬さ増加、靭性劣化により
ドリル寿命は短い。ａ２はＭｎ成分が規定範囲より少な
いため十分な量の硫化物が生成せずドリル寿命は短い。
ａ３はＭｎ成分が規定範囲を超えるため硬さ増加により
ドリル寿命は短い。ａ４，ａ５の場合ドリル寿命は開発
鋼並みであるが、ａ４では過剰なＳにより機械的性質が
大きく劣化するとともに鋳造時にはＣａＳの析出により
長時間鋳造を続けるのが困難である。ａ５では鋳造時に
はＡｌ２Ｏ３の析出により長時間鋳造を続けるのが困難
である。ａ６からａ９についてはＡｌ、Ｃａ成分が規定
範囲を外れるため、介在物中のＣａＯ、Ｃａ比率が小さ
くなってドリル寿命は短い。As shown in Tables 1 and 5, the steel of the present invention of A has a drill life of at least 14 or more. On the other hand, a1 is C
Drill life is short due to hardness increase and toughness deterioration because the component exceeds the specified range. In a2, since the Mn component is less than the specified range, a sufficient amount of sulfide is not generated and the drill life is short.
In a3, since the Mn component exceeds the specified range, the drill life is short due to an increase in hardness. In the case of a4 and a5, the drill life is about the same as that of the developed steel. However, in the case of a4, the mechanical properties are greatly deteriorated due to excessive S, and it is difficult to continue casting for a long time due to precipitation of CaS during casting. In a5, it is difficult to continue casting for a long time due to precipitation of Al 2 O 3 during casting. For a6 to a9, since the Al and Ca components are out of the specified ranges, the CaO and Ca ratios in the inclusions become small and the drill life is short.
【００４３】表１中のＢ、Ｃ、Ｄの発明鋼についてもＡ
発明鋼とほぼ同様な結果であった。The steels of the inventions B, C and D in Table 1
The results were almost the same as those of the invention steel.
【００４４】表６から明らかな様にＰｂ，Ｂｉ，Ｓｅ，
Ｔｅの各快削元素を添加する事によりドリル寿命は大幅
に長くなる。しかし、ｅ１からｅ４の様に、規格範囲を
超える過剰な添加は鋼の製造性を著しく悪化させる。As is clear from Table 6, Pb, Bi, Se,
The life of the drill is greatly increased by adding each free-cutting element of Te. However, as in the case of e1 to e4, excessive addition exceeding the specified range significantly deteriorates the productivity of steel.
【００４５】[0045]
【発明の効果】以上の説明で明らかな様に本発明鋼は、
機械的性質及び製造性の劣化を招くことなくドリル穴あ
け加工性を大幅に向上させる事ができるものである。こ
れにより、従来は機械的性質上の問題から被削性を犠牲
にしてきた機械構造部品への適用が可能となり、産業上
の利点が極めて大きい。As is clear from the above description, the steel of the present invention
Drilling workability can be significantly improved without deteriorating mechanical properties and manufacturability. As a result, the present invention can be applied to mechanical structural parts which have conventionally sacrificed machinability due to problems in mechanical properties, and have an extremely large industrial advantage.
Claims (2)
Ｓｉ：０．５０％以下、Ｍｎ：０．３０〜１．５０％、
Ｓ：０．０１〜０．０７％、Ａｌ：０．００２〜０．０
５％、Ｃａ：０．０００５〜０．００５％、Ｏ：０．０
００５〜０．００３％を含有し、残部がＦｅ及び不可避
不純物からなり、かつＣａＯを８〜６２％含むカルシウ
ムアルミネート酸化物介在物を内部に包み込んだ、長径
／短径比が５以下であるような紡錘型のＣａを１％以上
含むカルシウムマンガン硫化物介在物を含有することを
特徴とする機械的性質とドリル穴あけ加工性に優れた機
械構造用鋼。C. 0.10 to 0.60% by weight,
Si: 0.50% or less, Mn: 0.30 to 1.50%,
S: 0.01 to 0.07%, Al: 0.002 to 0.0
5%, Ca: 0.0005 to 0.005%, O: 0.0
005-0.003%, the balance being Fe and unavoidable impurities and enclosing a calcium aluminate oxide inclusion containing 8 to 62% of CaO, and having a major axis / minor axis ratio of 5 or less. A mechanical structural steel excellent in mechanical properties and drilling workability, characterized by containing such a spindle-type calcium manganese sulfide inclusion containing 1% or more of Ca.
重量％で、Ｐｂ：０．０４〜０．４％、Ｂｉ：０．０２
〜０．３％、Ｓｅ：０．１〜０．５％、Ｔｅ：０．００
３〜０．１％のうちの１種以上を含有し、残部がＦｅ及
び不可避不純物からなり、かつＣａＯを８〜６２％含む
カルシウムアルミネート酸化物介在物を内部に包み込ん
だ、長径／短径比が５以下であるような紡錘型のＣａを
１％以上含むカルシウムマンガン硫化物介在物を含有す
ることを特徴とする機械的性質とドリル穴あけ加工性に
優れた機械構造用鋼。2. Pb: 0.04 to 0.4%, Bi: 0.02 in weight% in addition to the alloy component according to claim 1.
0.3%, Se: 0.1-0.5%, Te: 0.00
A major axis / minor axis containing calcium aluminate oxide inclusions containing at least one of 3 to 0.1%, the balance being Fe and unavoidable impurities, and containing 8 to 62% of CaO. A mechanical structural steel excellent in mechanical properties and drilling workability, comprising spindle-type calcium manganese sulfide inclusions containing 1% or more of spindle-type Ca having a ratio of 5 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9131543A JPH10287953A (en) | 1997-04-16 | 1997-04-16 | Steel for machine structural use, excellent in mechanical property and drilling property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9131543A JPH10287953A (en) | 1997-04-16 | 1997-04-16 | Steel for machine structural use, excellent in mechanical property and drilling property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10287953A true JPH10287953A (en) | 1998-10-27 |
Family
ID=15060544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9131543A Pending JPH10287953A (en) | 1997-04-16 | 1997-04-16 | Steel for machine structural use, excellent in mechanical property and drilling property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10287953A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1264912A1 (en) * | 2001-06-08 | 2002-12-11 | Daido Steel Co., Ltd. | Free-cutting steel for machine structural use having good machinability in cutting by cemented carbide tool |
| WO2003064715A1 (en) * | 2002-01-29 | 2003-08-07 | Tanaka Seimitsu Kogyo Co., Ltd. | Bainite type non-refined steel for nitriding, method for production thereof and nitrided product |
| EP1063454A3 (en) * | 1999-06-25 | 2003-09-17 | Hitachi Metals, Ltd. | Self-lubricating piston ring material for internal combustion engine and piston ring |
| JP2005273000A (en) * | 2004-02-26 | 2005-10-06 | Sanyo Special Steel Co Ltd | Steel for machine structural use having improved machinability |
| JP2005350702A (en) * | 2004-06-08 | 2005-12-22 | Sanyo Special Steel Co Ltd | Steel having superior machinability for machine structural use |
| WO2005123973A1 (en) * | 2004-06-10 | 2005-12-29 | Hoeganaes Corporation | Powder metallurgical compositions and parts made therefrom |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS579860A (en) * | 1981-02-18 | 1982-01-19 | Daido Steel Co Ltd | Free cutting steel for high-performance gear and its manufacture |
| JPS5845351A (en) * | 1981-09-14 | 1983-03-16 | Daido Steel Co Ltd | Structural steel |
| JPS6050149A (en) * | 1983-08-26 | 1985-03-19 | Daido Steel Co Ltd | Structural steel |
| JPS62103340A (en) * | 1985-10-29 | 1987-05-13 | Kobe Steel Ltd | Ca free cutting steel for mechanical structure |
| JPH01168848A (en) * | 1987-12-23 | 1989-07-04 | Sanyo Special Steel Co Ltd | Universal free cutting steel for automobile parts and its production |
| JPH03177539A (en) * | 1989-12-07 | 1991-08-01 | Nippon Steel Corp | Electric resistance welded steel tube for machine structural use having excellent machinability |
-
1997
- 1997-04-16 JP JP9131543A patent/JPH10287953A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS579860A (en) * | 1981-02-18 | 1982-01-19 | Daido Steel Co Ltd | Free cutting steel for high-performance gear and its manufacture |
| JPS5845351A (en) * | 1981-09-14 | 1983-03-16 | Daido Steel Co Ltd | Structural steel |
| JPS6050149A (en) * | 1983-08-26 | 1985-03-19 | Daido Steel Co Ltd | Structural steel |
| JPS62103340A (en) * | 1985-10-29 | 1987-05-13 | Kobe Steel Ltd | Ca free cutting steel for mechanical structure |
| JPH01168848A (en) * | 1987-12-23 | 1989-07-04 | Sanyo Special Steel Co Ltd | Universal free cutting steel for automobile parts and its production |
| JPH03177539A (en) * | 1989-12-07 | 1991-08-01 | Nippon Steel Corp | Electric resistance welded steel tube for machine structural use having excellent machinability |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1063454A3 (en) * | 1999-06-25 | 2003-09-17 | Hitachi Metals, Ltd. | Self-lubricating piston ring material for internal combustion engine and piston ring |
| EP1264912A1 (en) * | 2001-06-08 | 2002-12-11 | Daido Steel Co., Ltd. | Free-cutting steel for machine structural use having good machinability in cutting by cemented carbide tool |
| WO2003064715A1 (en) * | 2002-01-29 | 2003-08-07 | Tanaka Seimitsu Kogyo Co., Ltd. | Bainite type non-refined steel for nitriding, method for production thereof and nitrided product |
| EP1471159A4 (en) * | 2002-01-29 | 2005-04-27 | Tanaka Seimitsu Kogyo Co Ltd | Bainite type non-refined steel for nitriding, method for production thereof and nitrided product |
| JP2005273000A (en) * | 2004-02-26 | 2005-10-06 | Sanyo Special Steel Co Ltd | Steel for machine structural use having improved machinability |
| JP2005350702A (en) * | 2004-06-08 | 2005-12-22 | Sanyo Special Steel Co Ltd | Steel having superior machinability for machine structural use |
| WO2005123973A1 (en) * | 2004-06-10 | 2005-12-29 | Hoeganaes Corporation | Powder metallurgical compositions and parts made therefrom |
| US7300489B2 (en) | 2004-06-10 | 2007-11-27 | Hoeganaes Corporation | Powder metallurgical compositions and parts made therefrom |
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