JP2000256805A - Heat resistant steel for cold forging - Google Patents
Heat resistant steel for cold forgingInfo
- Publication number
- JP2000256805A JP2000256805A JP11058132A JP5813299A JP2000256805A JP 2000256805 A JP2000256805 A JP 2000256805A JP 11058132 A JP11058132 A JP 11058132A JP 5813299 A JP5813299 A JP 5813299A JP 2000256805 A JP2000256805 A JP 2000256805A
- Authority
- JP
- Japan
- Prior art keywords
- resistant steel
- less
- cold forging
- heat
- cold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Heat Treatment Of Steel (AREA)
- Forging (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、高温環境において
使用される材料等に適した冷鍛性に優れた耐熱鋼に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant steel excellent in cold forgeability suitable for materials used in a high-temperature environment.
【０００２】[0002]
【従来の技術】従来、高温において使用されるマルテン
サイト系耐熱鋼は、冷間加工性が劣るため、通常は熱間
鍛造により、各部材は製造されている。そのため、加工
時の材料組織、硬さについては、それほど重要視されて
いなかった。しかしながら、熱間鍛造による製造では、
生産性、コストの面で冷間鍛造に比べて劣るという問題
があり、近年、これらマルテンサイト系耐熱鋼の冷鍛化
の開発が求められている。この場合、連続鍛造機等の使
用により、素材がそのまま加工されるため、素材の硬さ
は勿論のこと、材料組織が特に重要となる。このことか
ら、例えば特開平３−３６２３６号公報や特開平６−９
３３８４号公報等が開示されている。2. Description of the Related Art Conventionally, martensitic heat-resistant steels used at high temperatures are inferior in cold workability. Therefore, each member is usually manufactured by hot forging. Therefore, the material structure and hardness at the time of processing have not been given much importance. However, in production by hot forging,
There is a problem that it is inferior to cold forging in terms of productivity and cost. In recent years, development of cold forging of these martensitic heat-resistant steels has been required. In this case, since the material is processed as it is by using a continuous forging machine or the like, not only the hardness of the material but also the material structure is particularly important. From this, for example, Japanese Patent Application Laid-Open Nos. 3-36236 and 6-9
No. 3384 is disclosed.
【０００３】すなわち、特開平３−３６２３６号公報
は、重量比で、Ｃ：０．４５〜０．５０％、Ｓｉ：１．
００〜２．００％、Ｍｎ：０．６％以下、Ｐ：０．０３
０％以下、Ｓ：０．０１０％以下、Ｃｒ：７．５０〜
８．５０％、Ｏ：０．０１０％以下を含有し残部がＦｅ
ならびに不純物元素からなり、７５０〜８００℃の温度
で焼鈍することを特徴とする冷鍛用耐熱鋼にある。ま
た、特開平６−９３３８４号公報は、重量比にしてＣ：
０．３５〜０．４２％、Ｓｉ：１．８０〜２．２０％、
Ｍｎ：０．６０％以下、Ｓ：０．０１０％以下、Ｃｒ：
１０．００〜１１．００％、Ｍｏ：０．７０〜１．３０
％、Ｏ：０．０１０％以下を含有し、残部がＦｅおよび
不純物元素からなり、７５０〜８５０℃の温度で焼鈍す
ることを特徴とする冷鍛用耐熱鋼にある。[0003] That is, Japanese Patent Application Laid-Open No. 3-36236 discloses that C: 0.45 to 0.50%, Si: 1.
00 to 2.00%, Mn: 0.6% or less, P: 0.03
0% or less, S: 0.010% or less, Cr: 7.50 or more
8.50%, O: 0.010% or less, the balance being Fe
And a heat-resistant steel for cold forging characterized by being made of an impurity element and being annealed at a temperature of 750 to 800 ° C. JP-A-6-93384 discloses that the weight ratio of C:
0.35 to 0.42%, Si: 1.80 to 2.20%,
Mn: 0.60% or less, S: 0.010% or less, Cr:
10.00 to 11.00%, Mo: 0.70 to 1.30
%, O: 0.010% or less, the balance being Fe and impurity elements, and annealing at a temperature of 750 to 850 ° C.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上述し
た特許公報はいずれもマルテンサイト系耐熱鋼の冷鍛化
に重要となる焼なまし球状化率については一切触れられ
ていない。すなわち、この冷鍛用のマルテンサイト系耐
熱鋼を製造する場合、硬さを低下させるために焼なまし
処理を適用するが、素材硬さが同程度の材料でも、材料
組織の違いによって、冷間加工時の割れの発生しやすさ
が異なってくる。マルテンサイト系耐熱鋼の焼なまし材
料組織は、一般にパーライト組織、炭化物球状化組織、
またはそれらの混合組織のいずれかとなるが、パーライ
ト組織は、冷間加工時の割れの発生を助長しやすく、炭
化物球状化組織は、パーライト組織に比べて、割れの発
生が起こりにくい。よって、冷間加工性を向上されるた
めには、パーライト組織をできるだけ少なくし、炭化物
球状化組織の占める割合を増やすことが重要である。こ
の点に関する解明がされていないために、上記特許公報
の内容では冷鍛化を大きく向上させるには不十分であ
る。However, none of the above-mentioned patent publications mentions an annealing spheroidization rate which is important for cold forging of martensitic heat-resistant steel. In other words, when manufacturing this martensitic heat-resistant steel for cold forging, annealing is applied to reduce the hardness. The likelihood of cracking during hot working differs. The annealing material structure of martensitic heat-resistant steel generally has a pearlite structure, a carbide spheroidized structure,
Alternatively, the pearlite structure easily promotes cracking during cold working, and the carbide spheroidized structure is less likely to crack than the pearlite structure. Therefore, in order to improve the cold workability, it is important to reduce the pearlite structure as much as possible and increase the proportion of the carbide spheroidized structure. Since the elucidation on this point has not been made, the contents of the above-mentioned patent publications are not sufficient to greatly improve cold forging.
【０００５】[0005]
【課題を解決するための手段】上述のような問題を解消
するため、発明者らは鋭意開発を進めた結果、素材硬
さ、９５ＨＲＢ未満、好ましくは９０ＨＲＢ未満で、か
つ炭化物球状化率を８５％以上とすることで、冷鍛性を
大きく向上させることができる高温環境において使用さ
れる材料等に適した冷鍛性に優れた耐熱鋼を提供するも
のである。その発明の要旨とするところは、 （１）重量％で、Ｃ：０．３５〜０．７０％、Ｓｉ：
０．０５〜２．００％、Ｍｎ：０．１０〜１．００％、
Ｐ：０．０３５％以下、Ｓ：０．０１０％以下、Ｃｒ：
３．０〜１４．０％を含有し、残部がＦｅおよび不可避
的不純物からなるマルテンサイト系耐熱鋼において、炭
化物球状化率８５％以上としたことを特徴とする冷鍛用
耐熱鋼。Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have intensively developed and as a result, have found that the material hardness is less than 95 HRB, preferably less than 90 HRB, and the carbide spheroidization rate is 85%. % Or more, it is intended to provide a heat-resistant steel excellent in cold forgeability suitable for a material used in a high temperature environment and the like, which can greatly improve cold forgeability. The gist of the invention is as follows: (1) C: 0.35 to 0.70% by weight, Si:
0.05-2.00%, Mn: 0.10-1.00%,
P: 0.035% or less, S: 0.010% or less, Cr:
A heat-resistant steel for cold forging, characterized in that the martensitic heat-resistant steel contains 3.0 to 14.0% and the balance is Fe and inevitable impurities, and has a carbide spheroidization ratio of 85% or more.
【０００６】（２）前記（１）に記載の鋼に加えて、重
量％で、Ｎｉ：０．０５〜２．００％、Ｍｏ：０．０５
〜２．００％の１種または２種を添加してなることを特
徴とする冷鍛用耐熱鋼。 （３）前記（１）または（２）に記載の鋼において、
Ｏ：５０ｐｐｍ以下としたことを特徴とする冷鍛用耐熱
鋼にある。(2) In addition to the steel described in the above (1), Ni: 0.05 to 2.00%, Mo: 0.05 by weight%.
A heat-resistant steel for cold forging, characterized in that one or two kinds of 2.00% are added. (3) In the steel according to the above (1) or (2),
O: 50% or less in the heat-resistant steel for cold forging.
【０００７】[0007]
【発明の実施の形態】以下、本発明に係る化学成分とそ
の限定理由について説明する。 Ｃ：０．３５〜０．７０％ Ｃは高温強化を確保するために必要な元素であり、十分
な強度や耐摩耗性を得るためには、０．３５％添加する
必要がある。しかし、過度に添加すると優れた冷鍛性が
得られず、また、靱性も低下する。よって、上限を０．
７０％とした。 Ｓｉ：０．０５〜２．００％ Ｓｉは脱酸剤として、また耐酸化性を付与するために必
要な元素であるため、０．０５％以上添加するが、過度
に添加すると冷鍛性を劣化させるため、上限を２．００
％とした。BEST MODE FOR CARRYING OUT THE INVENTION The chemical components according to the present invention and the reasons for limiting them will be described below. C: 0.35 to 0.70% C is an element necessary for ensuring high-temperature strengthening, and 0.35% must be added to obtain sufficient strength and wear resistance. However, if added excessively, excellent cold forgeability cannot be obtained, and toughness also decreases. Therefore, the upper limit is set to 0.
70%. Si: 0.05 to 2.00% Since Si is an element necessary for providing a deoxidizing agent and imparting oxidation resistance, it is added in an amount of 0.05% or more. The upper limit is 2.00 to degrade
%.
【０００８】Ｍｎ：０．１０〜１．００％ Ｍｎは脱酸剤、脱硫剤として必要であり、下限を０．１
０％とした。また、過度に添加すると、耐酸化性、靱
性、冷間加工性が劣化するため上限を１．００％とし
た。 Ｐ：０．０３５％以下 Ｐは偏析を起こしやすく、靱性、冷間加工性が劣化する
ため、極力少ない方が好ましく、上限を０．０３５％と
した。Mn: 0.10-1.00% Mn is required as a deoxidizing agent and a desulfurizing agent, and the lower limit is 0.1%.
0%. Further, if added excessively, oxidation resistance, toughness and cold workability deteriorate, so the upper limit was made 1.00%. P: 0.035% or less P tends to cause segregation and deteriorates toughness and cold workability. Therefore, it is preferable that P is as small as possible, and the upper limit is made 0.035%.
【０００９】Ｓ：０．０１０％以下 Ｓは硫化物系介在物を形成し、冷間加工性が劣化させ、
また、偏析により靱性を劣化させるため、極力少ない方
が好ましく、上限を０．０１０％とした。 Ｃｒ：３．０〜１４．０％ Ｃｒは耐酸化性の向上に効果があり、下限を３．０％と
した。しかしながら、多量に添加するとコストアップを
招くため、上限を１４．０％とした。さらに、耐酸化性
を十分に確保するためには、Ｃｒは６．０〜１４．０％
にすることが好ましい。S: 0.010% or less S forms sulfide inclusions, deteriorating cold workability,
Further, in order to deteriorate toughness due to segregation, it is preferable that the amount is as small as possible. Cr: 3.0 to 14.0% Cr is effective in improving oxidation resistance, and the lower limit is set to 3.0%. However, if a large amount is added, the cost is increased. Therefore, the upper limit is set to 14.0%. Further, in order to ensure sufficient oxidation resistance, Cr is 6.0 to 14.0%.
Is preferable.
【００１０】Ｎｉ：０．０５〜２．００％ Ｎｉは焼入れ性の向上、強度の向上に有効であり、下限
を０．０５％とした。しかしながら多量に添加するとコ
ストアップを招くため、上限を２．０％とした。 Ｍｏ：０．０５〜２．００％ Ｍｏは高温強度の向上に効果があり、下限を０．０５％
とした。しかしながら、多量に添加するとコストアップ
を招き、靱性も低下するため上限を２．００％とした。 Ｏ：５０ｐｐｍ以下 Ｏは不可避的不純物元素であるが、冷間加工性を損なわ
ないために、５０ｐｐｍ以下が望ましい。Ni: 0.05 to 2.00% Ni is effective in improving hardenability and strength, with the lower limit being 0.05%. However, if a large amount is added, the cost is increased. Therefore, the upper limit is set to 2.0%. Mo: 0.05 to 2.00% Mo is effective in improving high-temperature strength, and the lower limit is 0.05%.
And However, if added in a large amount, the cost is increased and the toughness is also reduced. Therefore, the upper limit is set to 2.00%. O: 50 ppm or less O is an unavoidable impurity element, but is preferably 50 ppm or less so as not to impair cold workability.
【００１１】炭化物球状化率８５％以上 冷鍛用のマルテンサイト系耐熱鋼を製造する場合、硬さ
を低下させるために焼なまし処理を適用するが、素材硬
さが同程度の材料でも、材料組織の違いによって、冷間
加工時の割れの発生しやすさが異なってくる。冷間加工
用マルテンサイト系耐熱鋼の焼なまし処理を行った場
合、その材料組織は、パーライト組織、炭化物球状化組
織、またはその混合組織となるが、パーライト組織は、
冷間加工時の割れ発生を助長しやすく、球状炭化物組織
は、このパーライト組織に比べて、割れの発生が起こり
にくく、また、炭化物球状化組織の硬さは、パーライト
組織の硬さに比べて低いという特徴もある。よって、冷
鍛性を向上させるためには、パーライト組織をできるだ
け少なくし、球状炭化物組織とすることが非常に有効で
あり、特に冷間加工を可能にするためには、加工用素材
の炭化物球状化率を８５％以上にし、かつ、素材硬さが
９５ＨＲＢ未満、好ましくは９０ＨＲＢ未満とすること
が重要である。[0011] When producing a martensitic heat-resistant steel for cold forging, a spheroidization ratio of 85% or more, annealing is applied to reduce the hardness. The susceptibility to cracking during cold working differs depending on the difference in the material structure. When performing annealing treatment of martensitic heat-resistant steel for cold working, the material structure is a pearlite structure, a carbide spheroidized structure, or a mixed structure thereof, but the pearlite structure is
It is easy to promote cracking during cold working, the spherical carbide structure is less likely to crack than this pearlite structure, and the hardness of the carbide spheroidized structure is smaller than the hardness of the pearlite structure There is also a feature of low. Therefore, in order to improve the cold forgeability, it is very effective to reduce the pearlite structure as much as possible and to make it a spherical carbide structure. It is important that the conversion be 85% or more and the material hardness be less than 95 HRB, preferably less than 90 HRB.
【００１２】また、実際の工程においては、７５０〜８
８０℃の処理温度で、冷却速度２０℃／ｈ以下（冷却速
度が速すぎると球状炭化物組織となりにくいため）で、
焼なまし処理を行った後に、潤滑被膜処理や２０％以下
（材料が加工硬化しすぎないように２０％以下）の伸線
工程が一般に入る場合があるが、その場合にも炭化物球
状化率８５％以上で、かつ、素材硬さが９５ＨＲＢ未満
とした耐熱鋼にある。In actual steps, 750 to 8
At a processing temperature of 80 ° C., a cooling rate of 20 ° C./h or less (because it is difficult to form a spherical carbide structure if the cooling rate is too fast)
After the annealing treatment, the lubricating coating treatment and the wire drawing process of 20% or less (20% or less so that the material does not work harden) may enter the general process. The heat-resistant steel has a hardness of 85% or more and a material hardness of less than 95 HRB.
【００１３】[0013]
【実施例】表１に示す化学成分にて炭化物球状化率の異
なる供試材を作製し、径１４ｍｍ、長さ２１ｍｍの圧縮
試験片を採取し、圧縮試験を行い、割れの発生する限界
圧縮率をそれぞれ求めた。限界圧縮率が７８％以上のも
のを○、７０％以上のものを△、７０％未満のものを×
とした。その結果を表２に示す。この表２に示すように
炭化物球状化率８５％以上、素材硬さ９５ＨＲＢ以下、
好ましくは、９０ＨＲＢ以下の場合、それぞれの鋼種に
ついても良好な冷鍛性を示していることが判る。EXAMPLES Test materials having different carbide spheroidization ratios from the chemical components shown in Table 1 were prepared, compression test pieces having a diameter of 14 mm and a length of 21 mm were collected, subjected to a compression test, and subjected to critical compression at which cracking occurred. The rates were determined respectively.限界 when the limit compression ratio is 78% or more, Δ when the limit compression ratio is 70% or more, × when the limit compression ratio is less than 70%
And Table 2 shows the results. As shown in Table 2, the degree of carbide spheroidization is 85% or more, and the material hardness is 95HRB or less.
Preferably, in the case of 90HRB or less, it can be seen that each steel type shows good cold forgeability.
【００１４】[0014]
【表１】 [Table 1]
【００１５】[0015]
【表２】 [Table 2]
【００１６】[0016]
【発明の効果】以上述べたように、本発明により、高温
環境において使用される材料等に適した冷鍛性に優れた
マルテンサイト系耐熱鋼が安価に製造することが出来る
極めて優れた効果を奏するものである。As described above, according to the present invention, a martensitic heat-resistant steel excellent in cold forgeability suitable for materials used in a high-temperature environment can be produced at a low cost. To play.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 春名 靖志 兵庫県姫路市飾磨区中島字一文字3007番地 山陽特殊製鋼株式会社内 (72)発明者 磯本 辰郎 兵庫県姫路市飾磨区中島字一文字3007番地 山陽特殊製鋼株式会社内 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasushi Haruna 3007 one-letter Nakajima character in Shima-ku, Himeji City, Hyogo Prefecture Inside Sanyo Special Steel Co., Ltd. Special Steel Co., Ltd.
Claims (3)
ルテンサイト系耐熱鋼において、炭化物球状化率８５％
以上としたことを特徴とする冷鍛用耐熱鋼。C: 0.35 to 0.70%; Si: 0.05 to 2.00%; Mn: 0.10 to 1.00%; P: 0.035% or less; S: 0.010% or less, Cr: 3.0 to 14.0%, the balance being a martensitic heat-resistant steel comprising Fe and unavoidable impurities, and having a carbide spheroidization rate of 85%.
A heat-resistant steel for cold forging characterized by the above.
で、Ｎｉ：０．０５〜２．００％、Ｍｏ：０．０５〜
２．００％の１種または２種を添加してなることを特徴
とする冷鍛用耐熱鋼。2. In addition to the steel according to claim 1, in addition to the weight%
And Ni: 0.05-2.00%, Mo: 0.05-
A heat-resistant steel for cold forging characterized by adding one or two kinds of 2.00%.
Ｏ：５０ｐｐｍ以下としたことを特徴とする冷鍛用耐熱
鋼。3. The steel according to claim 1 or 2,
O: Heat-resistant steel for cold forging, characterized in that the content is 50 ppm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11058132A JP2000256805A (en) | 1999-03-05 | 1999-03-05 | Heat resistant steel for cold forging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11058132A JP2000256805A (en) | 1999-03-05 | 1999-03-05 | Heat resistant steel for cold forging |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000256805A true JP2000256805A (en) | 2000-09-19 |
Family
ID=13075469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11058132A Pending JP2000256805A (en) | 1999-03-05 | 1999-03-05 | Heat resistant steel for cold forging |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000256805A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014075202A1 (en) * | 2012-11-14 | 2014-05-22 | Compañía Electro Metalúrgica S.A. | Method for the production of high-wear-resistance martensitic cast steel and steel with said characteristics |
-
1999
- 1999-03-05 JP JP11058132A patent/JP2000256805A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014075202A1 (en) * | 2012-11-14 | 2014-05-22 | Compañía Electro Metalúrgica S.A. | Method for the production of high-wear-resistance martensitic cast steel and steel with said characteristics |
| CN105008554A (en) * | 2012-11-14 | 2015-10-28 | 电子冶金股份有限公司 | Method for the production of high-wear-resistance martensitic cast steel and steel with said characteristics |
| AU2013344748B2 (en) * | 2012-11-14 | 2017-04-20 | Compania Electro Metalurgica S.A. | Method for the production of high-wear-resistance martensitic cast steel and steel with said characteristics |
| CN105008554B (en) * | 2012-11-14 | 2019-01-15 | 电子冶金股份有限公司 | It is used to prepare the method for high-wearing feature martensitic cast steel and the steel with the characteristic |
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