JP2003013188A - Bi FREE-CUTTING STEEL - Google Patents
Bi FREE-CUTTING STEELInfo
- Publication number
- JP2003013188A JP2003013188A JP2001200475A JP2001200475A JP2003013188A JP 2003013188 A JP2003013188 A JP 2003013188A JP 2001200475 A JP2001200475 A JP 2001200475A JP 2001200475 A JP2001200475 A JP 2001200475A JP 2003013188 A JP2003013188 A JP 2003013188A
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- Prior art keywords
- steel
- free
- machinability
- inclusions
- cutting
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- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、環境に優しく被削
性に優れたPbレスのBi快削鋼に関するものである。特に
Ｂｉの溶解度が低い鋼において、ＢｉとともにＣｕ，Ｓ
ｎ等を溶鋼へ添加することにより、ＢｉとＣｕ，Ｓｎ等
の低融点合金の金属介在物を鋼中に多く導入することが
でき、少量のＢｉ量で被削性を大幅に向上させるもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Pb-less Bi free-cutting steel that is environmentally friendly and has excellent machinability. Especially in steels with low Bi solubility, Cu, S
By adding n etc. to the molten steel, it is possible to introduce a large amount of metal inclusions of Bi and low melting point alloys such as Cu and Sn into the steel, and to improve machinability significantly with a small amount of Bi. is there.
【０００２】[0002]
【従来の技術】従来、高快削性を要求される分野におい
ては、Ｐｂ快削鋼が広く使用されてきた。例えば、近
年、Ｍｎを低減し、ＭｎＳの比率を下げて耐食性を上げ
ると同時に、Ｐｂ，Ｔｅ，Ｓｅ等の快削元素を添加した
高機能快削ステンレス鋼が提案・実用化されいる（例え
ば、特開平１０−２３７６０３号公報）。しかしなが
ら、これらＰｂ等の毒性の強い快削元素は、近年の環境
問題から、規制される動きが強くなっており、製造がで
きなくなりつつある。2. Description of the Related Art Conventionally, Pb free-cutting steel has been widely used in fields where high free-cutting properties are required. For example, in recent years, high-performance free-cutting stainless steels containing free-cutting elements such as Pb, Te, and Se have been proposed and put into practical use while reducing Mn and lowering the ratio of MnS to improve corrosion resistance (for example, JP-A-10-237603). However, these highly toxic free-cutting elements, such as Pb, are being regulated due to recent environmental problems, and cannot be manufactured.
【０００３】一方、Ｐｂと同じような特性を示すＢｉは
希少元素であるが、毒性が低く、また、耐腐食性も高
い。そのため、Ｂｉ含有鋼は、環境調和型の高機能快削
鋼として有望視されている（例えば、特公平５−４５６
６１号公報）。しなかながら、Ｂｉは溶鋼に難溶解であ
り、蒸気圧も高い。ステンレス溶鋼に対しては特に難溶
解を示す。そのため、被削性を実現するために必要なＢ
ｉを添加すると、Ｂｉの難溶性に起因して熱間加工性が
劣化するという問題が発生していた。そのため、従来、
環境に優しいBi快削鋼は、世の中であまり使用されてい
ない。On the other hand, Bi, which has characteristics similar to Pb, is a rare element, but has low toxicity and high corrosion resistance. Therefore, the Bi-containing steel is regarded as a promising environment-friendly high-performance free-cutting steel (for example, Japanese Patent Publication No. 5-456).
No. 61). However, Bi is insoluble in molten steel and has a high vapor pressure. It is particularly difficult to melt in molten stainless steel. Therefore, B required to achieve machinability
When i was added, there was a problem that the hot workability was deteriorated due to the poor solubility of Bi. Therefore, conventionally,
Environmentally friendly Bi free-cutting steel is rarely used in the world.
【０００４】[0004]
【発明が解決しようとする課題】本発明は、上記のよう
なBi含有鋼の従来の欠点を解消するためになされたもの
であって、Ｃｕ，Ｓｎ等をＢｉとともに溶鋼へ添加する
ことにより被削性の向上を図り、これによって難溶解の
Ｂｉの添加を抑え、少量のＢｉ量で低融点のＢｉ系金属
介在物を鋼中に多く導入することを考案し、Ｐｂレスの
環境に優しいBi含有鋼（特にステンレス鋼）を安価に提
供することを目的としたものである。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks of Bi-containing steels, and is obtained by adding Cu, Sn and the like to Bi together with Bi. It was devised to improve the machinability, suppress the addition of insoluble Bi, and introduce a large amount of low melting point Bi-based metal inclusions into the steel with a small amount of Bi. The purpose is to provide contained steel (particularly stainless steel) at low cost.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、本発明者らは、溶鋼に難溶解を示すＢｉに対して、
ＦｅとＢｉの両方に親和性が強いＣｕ，Ｓｎ等をＢｉと
ともに溶鋼へ添加することで被削性の向上が可能であ
り、これによって熱間加工性などの製造性を劣化させる
難溶解のＢｉ量の添加を極力抑えて、低融点のＢｉ系金
属介在物を鋼中に多く導入し、Ｂｉ快削鋼の被削性を大
幅に向上できることを見出し、本発明をなしたのであ
る。In order to achieve the above-mentioned object, the present inventors have proposed that Bi, which hardly dissolves in molten steel,
It is possible to improve the machinability by adding Cu, Sn, etc., which have a strong affinity for both Fe and Bi, together with Bi to the molten steel, which makes it difficult to dissolve Bi, which deteriorates manufacturability such as hot workability. The present invention has been made based on the finding that it is possible to significantly reduce the machinability of Bi free-cutting steel by introducing a large amount of low melting point Bi-based metal inclusions into the steel by suppressing the addition of the amount as much as possible.
【０００６】すなわち、本発明の要旨とするところは以
下の通りである。
（１） 鋼中のＢｉ介在物にＣｕ，Ｓｎ，Ａｇ，Ｍｇの
うち１種以上の元素を含有しているＢｉ快削鋼。
（２） 鋼中のＢｉ介在物にＣｕ，Ｓｎ，Ａｇ，Ｍｇの
１種以上の元素が、質量％合計で平均２０％以上含まれ
る（１）記載のＢｉ快削鋼である。
（３） 前記（１）または（２）記載の組成が、質量％
でＣｒ：１１．０〜２５．０％を必須元素として含有す
るステンレス鋼において、Ｂｉ：０．０１〜０．１５％
を含有し、且つ、Ｃｕ：０．３〜３．０％，Ｓｎ：０．
０３〜０．３％，Ａｇ：０．０１〜０．２％，Ｍｇ：
０．００５〜０．０５％のうち１種以上を含有するＢｉ
快削鋼。
（４） 前記（３）記載のＢｉ快削鋼がフェライト系ス
テンレス鋼またはマルテンサイト系ステンレス鋼であ
る。That is, the gist of the present invention is as follows. (1) Bi free-cutting steel in which Bi inclusions in the steel contain one or more elements of Cu, Sn, Ag, and Mg. (2) The Bi free-cutting steel according to (1), wherein the Bi inclusions in the steel contain one or more elements of Cu, Sn, Ag, and Mg in an average of 20% or more in total by mass%. (3) The composition according to (1) or (2) above is% by mass.
In a stainless steel containing Cr: 11.0 to 25.0% as an essential element, Bi: 0.01 to 0.15%
And Cu: 0.3-3.0%, Sn: 0.
03-0.3%, Ag: 0.01-0.2%, Mg:
Bi containing at least one of 0.005 to 0.05%
Free cutting steel. (4) The Bi free-cutting steel described in (3) above is ferritic stainless steel or martensitic stainless steel.
【０００７】[0007]
【発明の実施の形態】以下に、請求項１，２記載の本発
明の限定理由について述べる。製造性を劣化させるＢｉ
の添加を最小限に抑えて、低融点の金属介在物を鋼中に
多く導入させることが被削性向上と製造性向上に有効で
ある。種々検討した結果、Ｃｕ，Ｓｎ，Ａｇ，ＭｇがＢ
ｉと相互作用が強く、溶鋼へＢｉとともに添加した場合
に、一部がＢｉと合金化して鋼中で低融点の金属介在物
を形成することがわかった。このとき、Ｂｉが存在せず
にＣｕ，Ｓｎ，Ａｇ，Ｍｇだけでは鋼中で低融点の金属
介在物を形成せず、Ｂｉが共存するときにのみ低融点の
金属介在物を形成する。これにより、従来に比較してＢ
ｉの添加量を少なくしても良好な被削性を実現すること
が可能になり、結果としてＢｉ快削鋼の熱間加工性を向
上させることができる。BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the present invention according to claims 1 and 2 will be described below. Bi that deteriorates manufacturability
It is effective to improve the machinability and the manufacturability by introducing a large amount of low-melting-point metal inclusions into the steel while minimizing the addition of Al. As a result of various studies, Cu, Sn, Ag, and Mg are B
It has been found that it has a strong interaction with i and when it is added to molten steel together with Bi, a part of it is alloyed with Bi to form a metal inclusion having a low melting point in the steel. At this time, Cu, Sn, Ag, and Mg alone without Bi do not form a low-melting metal inclusion in the steel, but form a low-melting metal inclusion only when Bi coexists. As a result, B
Good machinability can be realized even if the addition amount of i is reduced, and as a result, the hot workability of the Bi free-cutting steel can be improved.
【０００８】また、前記のＢｉ介在物において、Ｃｕ，
Ｓｎ，Ａｇ，Ｍｇのうち１種以上の元素をあわせて、質
量％で平均２０％以上含有させると、さらに被削性向上
と製造性向上の効果が大きくなる。好ましくは３０％以
上である。In the above Bi inclusion, Cu,
When one or more elements of Sn, Ag, and Mg are combined and contained in an average of 20% or more by mass%, the effect of improving machinability and manufacturability is further enhanced. It is preferably 30% or more.
【０００９】次に、請求項３，４記載の本発明の限定理
由について述べる。Ｃｒを含有するステンレス鋼では特
に、Ｂｉが難溶解を示し、前記課題が大きくなる。その
ため、Ｃｒ：１１．０〜２５．０％を必須元素として含
有するステンレス鋼では、本発明の効果が特に大きくな
る。尚、ＮｉはＢｉの溶解度を上げる作用があることか
ら、ステンレス鋼の中でもＮｉを殆ど含有しないフェラ
イト系ステンレス鋼やマルテンサイト系ステンレス鋼
で、本発明の効果が特に大きくなる。好ましくは１２％
〜２０％である。Next, the reasons for limitation of the present invention according to claims 3 and 4 will be described. In the case of stainless steel containing Cr in particular, Bi is difficult to dissolve, and the above-mentioned problems are increased. Therefore, the effect of the present invention is particularly large in stainless steel containing Cr: 11.0 to 25.0% as an essential element. Since Ni has a function of increasing the solubility of Bi, the effects of the present invention are particularly large in ferritic stainless steels and martensitic stainless steels containing almost no Ni among stainless steels. Preferably 12%
~ 20%.
【００１０】ここで、Ｂｉは鋼中で低融点のＢｉ介在物
を形成し、鋼に快削性を付与するため、０．０１％以上
添加する。しかしながら、０．１５％を超えて添加する
と製造性が著しく劣化する。そのため、０．０１％〜
０．１５％に限定した。好ましくは０．０５％〜０．１
３％である。本発明は、Ｃｕ，Ｓｎ，Ａｇ，Ｍｇのうち
１種以上をＢｉとともに添加するので、Ｂｉ含有量が
０．１５％以下であっても良好な被削性を実現すること
ができ、その結果良好な熱間加工性を維持することがで
きる。Here, Bi forms a low-melting-point Bi inclusion in the steel and adds 0.01% or more in order to impart free-cutting property to the steel. However, if added over 0.15%, the manufacturability is significantly deteriorated. Therefore, 0.01% ~
It was limited to 0.15%. Preferably 0.05% to 0.1
3%. In the present invention, one or more of Cu, Sn, Ag, and Mg are added together with Bi, so that good machinability can be realized even when the Bi content is 0.15% or less. Good hot workability can be maintained.
【００１１】Ｃｕは、Ｂｉと低融点の金属介在物を鋼中
に形成させて被削性を向上させるとともにＢｉ添加量を
抑制できるため、０．３％以上添加する。しかしなが
ら、３．５％を超えて添加すると熱間製造性が劣化す
る。そのため、上限を３．０％に限定した。好ましく
は、０．５％〜２．０％である。Cu is added in an amount of 0.3% or more because it forms a metal inclusion having a low melting point with Bi in steel to improve machinability and suppresses the amount of addition of Bi. However, if added over 3.5%, hot manufacturability deteriorates. Therefore, the upper limit is limited to 3.0%. Preferably, it is 0.5% to 2.0%.
【００１２】Ｓｎは、Ｃｕと同じような効果で、Ｂｉと
低融点の金属介在物を鋼中に形成させて被削性を向上さ
せるとともにＢｉ添加量を抑制できるため、０．０３％
以上添加する。しかしながら、０．３％を超えて添加す
ると熱間製造性が劣化する。そのため、上限を０．３％
に限定した。好ましくは０．０５％〜０．２％である。[0012] Sn has the same effect as Cu and forms metal inclusions having a low melting point with Bi in the steel to improve the machinability and to suppress the Bi addition amount.
The above is added. However, if added in excess of 0.3%, hot manufacturability deteriorates. Therefore, the upper limit is 0.3%
Limited to. It is preferably 0.05% to 0.2%.
【００１３】Ａｇは、Ｃｕと同じような効果で、Ｂｉと
低融点の金属介在物を鋼中に形成させて被削性を向上さ
せるとともにＢｉ添加量を抑制できるため、０．０１％
以上添加する。しかしながら、０．２％を超えて添加す
ると製造性が劣化する。そのため、上限を０．２％に限
定した。好ましくは０．０５〜０．１５％である。[0013] Ag has an effect similar to that of Cu, and forms a metal inclusion having a low melting point with Bi in steel to improve machinability and to suppress the addition amount of Bi.
The above is added. However, if over 0.2% is added, the manufacturability deteriorates. Therefore, the upper limit is limited to 0.2%. It is preferably 0.05 to 0.15%.
【００１４】Ｍｇは、Ｃｕと同じような効果で、Ｂｉと
低融点の金属介在物を鋼中に形成させて被削性を向上さ
せるとともにＢｉ添加量を抑制できるため、０．００５
％以上添加する。しかしながら、０．０５％を超えて添
加すると硬質な粗大非金属介在物が形成して切削性が劣
化する。そのため、上限を０．０５％に限定する。[0014] Mg has the same effect as Cu, because it forms a metal inclusion having a low melting point with Bi in the steel to improve the machinability and can suppress the Bi addition amount.
% Or more. However, if added in excess of 0.05%, hard coarse nonmetallic inclusions are formed and the machinability deteriorates. Therefore, the upper limit is limited to 0.05%.
【００１５】[0015]
【実施例】表１に示す化学成分の供試鋼を１００ｋｇ真
空溶解し、溶鋼温度が１６００〜１６５０℃で、表２に
組成を示すような粒状のＢｉ合金（φ約１０ｍｍ前後）
を溶鋼上方から添加して、３分後に上方から約３００ｇ
の溶鋼をサンプリングした。その後、残りを鋳型に鋳造
した。溶解後、３００ｇサンプリング材のチェック分析
を行い、製品の化学成分とした。[Examples] 100 kg of test steels having the chemical compositions shown in Table 1 were vacuum melted, and the molten steel temperature was 1600 to 1650 ° C, and a granular Bi alloy having the composition shown in Table 2 (φ about 10 mm)
Is added from above the molten steel, and after 3 minutes, about 300 g from above
Molten steel was sampled. Then, the rest was cast in a mold. After the dissolution, 300 g sampling material was subjected to check analysis and used as a chemical component of the product.
【００１６】鋳造後、これらの鋼塊を熱間加工し、φ２
１mmの棒鋼にした。その後、焼鈍・酸洗を行い、冷間引
き抜き加工およびセンタレス加工により、２０ｍｍφの
摩棒に仕上げた。After casting, these steel ingots were hot worked to obtain φ2
1mm steel bar was used. After that, annealing and pickling were performed, and cold drawing and centerless processing were performed to obtain a 20 mmφ rod.
【００１７】評価として、Ｂｉ介在物の組成と切削性，
熱間製造性を評価した。Ｂｉ介在物の組成について、摩
棒の縦断面を鏡面研磨し、ＥＰＭＡのＭＡＰ分析により
Ｂｉ介在物の位置を調査して、その後、１０箇所の点分
析の平均によりＢｉ介在物の組成を調査した。なお、Ｍ
ＡＰ分析の測定条件については、加速電圧；１５ｋＶ，
照射電流；２．４１×１０-9Ａ，ビーム径；１μm，照
射時間；１０ｍｓとした。また、点分析の測定条件につ
いては、加速電圧；１５ｋＶ，照射電流；１×10-8Ａ，
ビーム径；１μm，照射時間；２０ｓ（バックグランド
補正時間内１０ｓ）とした。As an evaluation, the composition and machinability of Bi inclusions,
The hot manufacturability was evaluated. Regarding the composition of Bi inclusions, the longitudinal section of the rod was mirror-polished, the position of Bi inclusions was investigated by MAP analysis of EPMA, and then the composition of Bi inclusions was investigated by the average of 10 point analysis. . In addition, M
Regarding the measurement conditions for AP analysis, acceleration voltage: 15 kV,
Irradiation current: 2.41 × 10 −9 A, beam diameter: 1 μm, irradiation time: 10 ms. Regarding the measurement conditions of the point analysis, acceleration voltage: 15 kV, irradiation current: 1 × 10 −8 A,
The beam diameter was 1 μm, and the irradiation time was 20 s (the background correction time was 10 s).
【００１８】切削性は、この摩棒を表３に示す条件で切
削試験を行い、被削性を評価した。なお、被削性の評価
は工具寿命と切屑形状で行った。工具寿命はフランク摩
耗量で評価し、30min後のフランク摩耗量を評価した。
また、切屑形状は規則的にカール状に分断されていれば
○，不規則な形の連続切屑の場合は×とした。The machinability was evaluated by performing a cutting test on the bar under the conditions shown in Table 3. The machinability was evaluated based on the tool life and chip shape. The tool life was evaluated by the amount of flank wear, and the amount of flank wear after 30 minutes was evaluated.
In addition, the chip shape was rated as ◯ if it was regularly divided into curls, and as x if it was an irregular continuous chip.
【００１９】熱間製造性は、上記鋳片の表層から試験片
（φ８ｍｍ×１１０ｍｍ）を切り出し、熱間引張試験に
よって熱間加工性を評価した。評価は１０００℃におけ
る破断絞り値で行った。For hot workability, a test piece (φ8 mm × 110 mm) was cut out from the surface layer of the cast piece, and hot workability was evaluated by a hot tensile test. The evaluation was performed by the breaking aperture value at 1000 ° C.
【００２０】まず、鋼中のＢｉ介在物にＣｕ，Ｓｎ，Ａ
ｇ，Ｍｇのうち１種以上の元素を含有している本発明の
効果について述べる。表４に製品の化学成分を質量％で
示し、また、その特性評価結果を表５に示す。表４中の
「＊」は、成分値が本発明範囲外であることを示す。First, Cu, Sn, A was added to Bi inclusions in the steel.
The effect of the present invention containing at least one element of g and Mg will be described. Table 4 shows the chemical components of the products in mass%, and Table 5 shows the results of their characteristic evaluations. "*" In Table 4 indicates that the component value is outside the range of the present invention.
【００２１】[0021]
【表１】 [Table 1]
【００２２】[0022]
【表２】 [Table 2]
【００２３】[0023]
【表３】 [Table 3]
【００２４】[0024]
【表４】 [Table 4]
【００２５】[0025]
【表５】 [Table 5]
【００２６】本発明例No.1と比較例No.11は0.6%C-0.05%
Biの炭素鋼を基本成分として本発明の効果を確認したも
のである。Ｂｉ添加量が同じにも関わらず、本発明例N
o.1ではBi介在物が合金化しているため、比較例No.11に
比べ切削性に優れる。Inventive Example No. 1 and Comparative Example No. 11 are 0.6% C-0.05%
The effect of the present invention was confirmed using Bi carbon steel as a basic component. Inventive Example N in spite of the same Bi addition amount
In o.1, since Bi inclusions are alloyed, the machinability is superior to Comparative Example No.11.
【００２７】本発明例No.2と比較例No.12は0.1%C-0.3%S
の炭素鋼を基本成分として本発明の効果を確認したもの
である。本発明例No.2はBi介在物が合金化しているた
め、比較例No.12に比べＢｉ量が少ないが、同等の切削
性を示す。一方、Bi量が多く添加させている比較例No.1
2は熱間製造性に劣る。以上、炭素鋼において本発明の
優位性は明らかである。Inventive example No. 2 and comparative example No. 12 are 0.1% C-0.3% S
The effect of the present invention was confirmed by using the above carbon steel as a basic component. Inventive Example No. 2 has a smaller amount of Bi than Comparative Example No. 12 because Bi inclusions are alloyed, but exhibits the same machinability. On the other hand, Comparative Example No. 1 containing a large amount of Bi
2 is inferior in hot manufacturability. As described above, the superiority of the present invention in carbon steel is clear.
【００２８】本発明例No.3と比較例No.13はオーステナ
イト系ステンレス鋼を基本成分として本発明の効果を確
認したものである。本発明例No.3はBi介在物が合金化し
ているため、比較例No.13に比べBi量が少ないが、同等
の切削性を示す。一方、Bi量が多く添加させている比較
例No.13は熱間製造性に劣る。Inventive Example No. 3 and Comparative Example No. 13 confirmed the effect of the present invention using austenitic stainless steel as a basic component. Inventive Example No. 3 has a smaller amount of Bi than Comparative Example No. 13 because Bi inclusions are alloyed, but shows the same machinability. On the other hand, Comparative Example No. 13 containing a large amount of Bi is inferior in hot manufacturability.
【００２９】本発明例No.4〜8と比較例No.14〜19は19%C
rのフェライト系ステンレス鋼を基本成分として本発明
の効果を確認したものである。本発明例No.4〜8はBi介
在物が合金化しているため工具寿命も100μm以下であ
り、切屑処理性も良好である。Inventive Examples Nos. 4 to 8 and Comparative Examples Nos. 14 to 19 had 19% C
The effect of the present invention was confirmed by using ferritic stainless steel of r as a basic component. Inventive Examples Nos. 4 to 8 have a tool life of 100 μm or less because the Bi inclusions are alloyed, and have good chip disposability.
【００３０】一方、Bi添加量が本発明例No.4と同じ比較
例No.14は、Bi介在物が合金化しておらず、工具寿命お
よび切屑処理性に劣る。On the other hand, Comparative Example No. 14 in which the amount of Bi added is the same as Example No. 4 of the present invention, Bi inclusions are not alloyed, and the tool life and chip disposability are poor.
【００３１】また、比較例No.15〜18はBi，Cu，Sn，Ag
添加量がそれぞれ多いため、切削性は本発明例No.4〜8
並に優れるものの熱間製造性が著しく劣化している。ま
た、比較例No.19はMg添加量が多いため、切削性（工具
寿命）に劣っている。Comparative examples Nos. 15 to 18 are Bi, Cu, Sn and Ag.
Since the addition amount is large, the machinability is inferior to Invention Example No. 4 to 8
Although excellent, the hot workability is significantly deteriorated. Further, Comparative Example No. 19 is inferior in machinability (tool life) due to the large amount of Mg added.
【００３２】本発明例No.9と比較例No.20は19%Cr-0.3%S
のフェライト系ステンレス鋼を基本成分として本発明の
効果を確認したものである。本発明例No.9はBi介在物が
合金化しているため、比較例No.20に比べBi量が少ない
が、同等の切削性を示す。一方、Bi量が多く添加させて
いる比較例No.20は熱間製造性に劣る。Inventive Example No. 9 and Comparative Example No. 20 are 19% Cr-0.3% S
The effect of the present invention was confirmed by using the above ferritic stainless steel as a basic component. Inventive Example No. 9 has a Bi content smaller than that of Comparative Example No. 20 because Bi inclusions are alloyed, but exhibits the same machinability. On the other hand, Comparative Example No. 20 containing a large amount of Bi is inferior in hot manufacturability.
【００３３】本発明例No.10と比較例No.21はマルテンサ
イト系ステンレス鋼を基本成分として本発明の効果を確
認したものである。Ｂｉ添加量が同じにも関わらず、本
発明例No.10ではBi介在物が合金化しているため、比較
例No.20に比べ切削性に優れる。Inventive Example No. 10 and Comparative Example No. 21 confirmed the effects of the present invention using martensitic stainless steel as a basic component. Despite the same amount of Bi added, inventive example No. 10 is superior in machinability as compared with comparative example No. 20 because the Bi inclusions are alloyed.
【００３４】以上、ステンレス鋼においても本発明の効
果は明らかである。但し、オーステナイト系ステンレス
鋼では、基本の熱間製造性が劣るため本発明の効果が小
さい。As described above, the effect of the present invention is clear even for stainless steel. However, austenitic stainless steel is inferior in basic hot manufacturability, so that the effect of the present invention is small.
【００３５】次に、鋼中のＢｉ介在物にＣｕ，Ｓｎ，Ａ
ｇ，Ｍｇの１種以上の元素が、質量％で平均２０％以上
含有することの請求項２の発明効果について述べる。表
６に製品の化学成分を質量％で示し、また、その特性評
価結果を表７に示す。Next, Cu, Sn, and A were added to Bi inclusions in the steel.
The invention effect of claim 2 in which one or more elements of g and Mg are contained in an average of 20% or more by mass% will be described. Table 6 shows the chemical components of the products in mass%, and Table 7 shows the results of their characteristic evaluations.
【００３６】[0036]
【表６】 [Table 6]
【００３７】[0037]
【表７】 [Table 7]
【００３８】本発明例No.22〜25と比較例No.26〜28は19
%Crのフェライト系ステンレス鋼を基本成分として本発
明の効果を確認したものである。Bi介在物中のＣｕ，Ｓ
ｎ，Ａｇ，Ｍｇの１種以上の元素濃度が低くなる程、す
なわち、Bi濃度が高くなる程、切削性が劣化している。
Bi介在物中のBi濃度が80%以上を示す比較例No.26〜28で
は切削性が劣化している。Inventive Examples Nos. 22 to 25 and Comparative Examples Nos. 26 to 28 are 19
The effect of the present invention was confirmed by using ferritic stainless steel of% Cr as a basic component. Cu and S in Bi inclusions
The lower the concentration of one or more elements of n, Ag, and Mg, that is, the higher the concentration of Bi, the worse the machinability.
The machinability is deteriorated in Comparative Examples Nos. 26 to 28 in which the Bi concentration in the Bi inclusions is 80% or more.
【００３９】[0039]
【発明の効果】本発明は、溶鋼に難溶解を示すＢｉに対
して、ＦｅとＢｉの両方に親和性が強いＣｕ，Ｓｎ等と
ともに溶鋼へ添加することで、製造性を劣化させる難溶
解のＢｉ量の添加を抑えて、低融点のＢｉ系金属介在物
を鋼中に多く導入でき、Ｂｉ含有鋼の被削性を大幅に向
上できるものである。INDUSTRIAL APPLICABILITY According to the present invention, when Bi, which hardly dissolves in molten steel, is added to the molten steel together with Cu, Sn, etc., which have a strong affinity for both Fe and Bi, it is possible to improve the productivity. By suppressing the addition of the Bi amount, a large amount of low melting point Bi-based metal inclusions can be introduced into the steel, and the machinability of the Bi-containing steel can be significantly improved.
Claims (4)
Ｍｇのうち１種以上の元素を含有していることを特徴と
するＢｉ快削鋼。1. A Bi inclusion in steel containing Cu, Sn, Ag,
Bi free-cutting steel containing at least one element of Mg.
Ｍｇの１種以上の元素が、質量％合計で平均２０％以上
含まれることを特徴とする請求項１記載のＢｉ快削鋼。2. The Bi inclusions in the steel containing Cu, Sn, Ag,
The Bi free-cutting steel according to claim 1, characterized in that one or more elements of Mg are contained in an average of 20% or more in total of mass%.
必須元素として含有するステンレス鋼において、Ｂｉ：
０．０１〜０．１５％を含有し、且つ、Ｃｕ：０．３％
〜３．０％，Ｓｎ：０．０３〜０．３％，Ａｇ：０．０
１〜０．２％，Ｍｇ：０．００５〜０．０５％のうち１
種以上を含有することを特徴とする請求項１または２記
載のＢｉ快削鋼。3. A stainless steel containing Cr: 11.0 to 25.0% by mass as an essential element, wherein Bi:
Contains 0.01 to 0.15% and Cu: 0.3%
~ 3.0%, Sn: 0.03-0.3%, Ag: 0.0
1 to 0.2%, Mg: 0.005 to 0.05%, 1
The Bi free-cutting steel according to claim 1 or 2, containing at least one kind.
ンサイト系ステンレス鋼であることを特徴とする請求項
３記載のＢｉ快削鋼。4. The Bi free cutting steel according to claim 3, which is a ferritic stainless steel or a martensitic stainless steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001200475A JP4979162B2 (en) | 2001-07-02 | 2001-07-02 | Bi free cutting steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001200475A JP4979162B2 (en) | 2001-07-02 | 2001-07-02 | Bi free cutting steel |
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| Publication Number | Publication Date |
|---|---|
| JP2003013188A true JP2003013188A (en) | 2003-01-15 |
| JP4979162B2 JP4979162B2 (en) | 2012-07-18 |
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|---|---|---|---|
| JP2001200475A Expired - Lifetime JP4979162B2 (en) | 2001-07-02 | 2001-07-02 | Bi free cutting steel |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1738926A1 (en) * | 2004-03-18 | 2007-01-03 | Sakura Color Products Corporation | Ball-point pen tip |
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|---|---|---|---|---|
| JPS62274048A (en) * | 1986-05-21 | 1987-11-28 | Daido Steel Co Ltd | Free-cutting steel |
| JPS62278252A (en) * | 1986-05-28 | 1987-12-03 | Daido Steel Co Ltd | Free-cutting austenitic stainless steel |
| JPS63250440A (en) * | 1987-04-08 | 1988-10-18 | Daido Steel Co Ltd | Steel for cutting tool |
| JPS648258A (en) * | 1987-06-30 | 1989-01-12 | Aichi Steel Works Ltd | Martensitic free-cutting stainless steel for cold forging |
| JPH03180449A (en) * | 1989-12-11 | 1991-08-06 | Daido Steel Co Ltd | Ferritic free-cutting stainless steel excellent in cold workability, toughness, corrosion resistance, and machinability and its production |
| JPH0978187A (en) * | 1995-09-07 | 1997-03-25 | Daido Steel Co Ltd | Free-cutting steel for plating |
| JPH10237593A (en) * | 1997-02-20 | 1998-09-08 | Nippon Steel Corp | Rod wire for reinforcing concrete excellent in wire saw cuttability |
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2001
- 2001-07-02 JP JP2001200475A patent/JP4979162B2/en not_active Expired - Lifetime
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62274048A (en) * | 1986-05-21 | 1987-11-28 | Daido Steel Co Ltd | Free-cutting steel |
| JPS62278252A (en) * | 1986-05-28 | 1987-12-03 | Daido Steel Co Ltd | Free-cutting austenitic stainless steel |
| JPS63250440A (en) * | 1987-04-08 | 1988-10-18 | Daido Steel Co Ltd | Steel for cutting tool |
| JPS648258A (en) * | 1987-06-30 | 1989-01-12 | Aichi Steel Works Ltd | Martensitic free-cutting stainless steel for cold forging |
| JPH03180449A (en) * | 1989-12-11 | 1991-08-06 | Daido Steel Co Ltd | Ferritic free-cutting stainless steel excellent in cold workability, toughness, corrosion resistance, and machinability and its production |
| JPH0978187A (en) * | 1995-09-07 | 1997-03-25 | Daido Steel Co Ltd | Free-cutting steel for plating |
| JPH10237593A (en) * | 1997-02-20 | 1998-09-08 | Nippon Steel Corp | Rod wire for reinforcing concrete excellent in wire saw cuttability |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1738926A1 (en) * | 2004-03-18 | 2007-01-03 | Sakura Color Products Corporation | Ball-point pen tip |
| EP1738926A4 (en) * | 2004-03-18 | 2010-07-07 | Sakura Color Prod Corp | Ball-point pen tip |
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| Publication number | Publication date |
|---|---|
| JP4979162B2 (en) | 2012-07-18 |
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