JPH0313525A - Production of high-mn nonmagnetic steel having excellent sr brittle resistant characteristic, high strength and high toughness - Google Patents
Production of high-mn nonmagnetic steel having excellent sr brittle resistant characteristic, high strength and high toughnessInfo
- Publication number
- JPH0313525A JPH0313525A JP14736789A JP14736789A JPH0313525A JP H0313525 A JPH0313525 A JP H0313525A JP 14736789 A JP14736789 A JP 14736789A JP 14736789 A JP14736789 A JP 14736789A JP H0313525 A JPH0313525 A JP H0313525A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- toughness
- nonmagnetic
- nonmagnetic steel
- strength
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 41
- 239000010959 steel Substances 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 238000010438 heat treatment Methods 0.000 claims abstract description 16
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 12
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 7
- 238000005098 hot rolling Methods 0.000 claims abstract description 4
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 3
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 230000001105 regulatory effect Effects 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 26
- 238000000137 annealing Methods 0.000 abstract description 7
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 7
- 238000005482 strain hardening Methods 0.000 abstract description 7
- 238000003466 welding Methods 0.000 abstract description 6
- 229910052759 nickel Inorganic materials 0.000 abstract description 4
- 229910052718 tin Inorganic materials 0.000 abstract description 4
- 229910052787 antimony Inorganic materials 0.000 abstract description 3
- 229910052785 arsenic Inorganic materials 0.000 abstract description 3
- 238000005096 rolling process Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 15
- 229910001566 austenite Inorganic materials 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 5
- 238000011282 treatment Methods 0.000 description 5
- 238000011276 addition treatment Methods 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
（産業上の利用分野）
本発明は核融合炉、リニアモーター力軌道設備。
各種発電機などに使用される非磁性構造用鋼に係り、特
に溶接後或いは冷間加工後に６００〜７゜０℃での応力
除力焼鈍が行われる部材に好適な高Ｍｎ非磁性鋼の製造
方法に関するものである。
（従来の技術及び解決しようとする課Ｍ）高Ｍｎ非磁性
鋼は、従来の代表的非磁性鋼であるオーステナイト系ス
テンレス鋼と比べ、高強度で磁気特性にも優れ、かつ低
源であることから、オーステナイト系ステンレス鋼に代
わり、その使用量が年々増大している。
しかしながら、従来の高Ｍｎ非磁性鋼は、１．０％Ｃ−
１３％Ｍｎ鋼や、０．４５％Ｃ−１８％Ｍｎ−５％Ｃｒ
鋼に代表されるようにＣ含有量が比較的高いため、６０
０〜７００℃に加熱されると炭化物の析出に起因する延
性、靭性の劣化が生ずる。
そのため、溶接後或いは冷間加工後の残留応力除去処理
が必要な場合、このような温度域での応力除去焼鈍（Ｓ
Ｒ）が実施できないという問題がある。
すなわち、溶接後或いは冷間加工後のＳＲにおいて、こ
の温度域を避けて９００〜１１００’Ｃの高温で処理し
たり、或いは冷間加工を熱間加工に変更するなどで対処
しているのが実情である。しかし、このような対処法は
、経済性を損なうことは勿論であるが、鋼材の強度低下
という問題もある。
本発明の目的は、上述の現状に鑑み、高Ｍｎ非磁性鋼の
有する基本的特性を損なうことなく、６００〜７００℃
の応力除去焼鈍後においても良好な機械的性質を有する
高Ｍｎ非磁性鋼を製造し得る方法を提供することにある
。
（課題を解決するための手段）
前記目的を達成するため１本発明者は、高Ｍｎ非磁性鋼
の化学成分並びに製造条件について鋭意研究を重ねた結
果、ここに本発明をなしたものである。
すなわち、本発明は、Ｃ：０．１０〜０．７０％、Ｓｉ
：０．１０〜１．５０％、Ｍｎ：１０〜３０％、Ｐ：０
．０３０％以下、ｓ：ｏ、ｏｌ ５％以下、Ｍｏ：Ｏ。
０５〜２．００％及びＢ：Ｏ，ＯＯＯ５〜０．００５０
％を含有し、かつ、２０×Ｃ＋Ｍｎ≧２４％を満足し、
必要に応じて、更に、Ｓｎ＋Ｓｂ＋Ａｓを総量で０．０
２０％以下に規制し、或いは更に、Ｎｉ：０．１０〜３
．００％及びＣｒ：０．１０〜８．００％の１種又は２
種を含有し、残部が鉄よりなる鋼を、１０５０〜１２５
０℃に加熱後、仕上温度を８００℃以上に制御した熱間
圧延を行い、その後の冷却過程において、少なくとも７
５０〜５５０℃の温度領域を１’Ｃ／ｓｅｅ以上の冷却
速度で冷却することを特徴とする耐ＳＲ脆化特性が優れ
、且つ高強度、高靭性を有する高Ｍｎ非磁性鋼の製造方
法を要旨とするものである。
以下に本発明を更に詳細に説明する。
（発明の構成）
まず、本発明における化学成分の限定理由は以下のとお
りである。
Ｃ：
Ｃはオーステナイトの安定化と強度の向上に有効な元素
である。しかし、０．１０％未満ではオーステナイトの
安定化、強度確保のために、Ｍｎ、Ｎｉ、Ｃｒ、Ｍｏな
どの元素を多量に添加する必要があり、経済性を大きく
損なうことになる。また０、７０％を超えて含有すると
、熱間加工性や機械加工性が劣化する。したがって、Ｃ
含有量は０．１０〜０．７０％の範囲とする。
Ｓｉ：
ＳＬは鋼溶解時の脱酸作用を有し、かつ強度の向上に有
効であるため、０．１０％以上を添加する。しかし、１
．５０％を超えて添加すると熱間加工性を損なうことに
なる。したがって、Ｓｉ含有量は０．１０〜１．５０％
の範囲とする。
Ｍｒｌ：
Ｍｎは本発明鋼においてＣと共に重要なオーステナイト
形成元素であり、非磁性を安定化させるために１０％以
上の添加が必要である。しかし、３０％を超えて含有す
ると熱間加工性が著しく劣化する。したがって、Ｍｎ含
有量は１０〜３０％の範囲とする。
但し、本発明鋼では基本的にはＣとＭｎでオーステナイ
トを安定化し、非磁性を確保できるが、Ｃ，Ｍｎともに
上記範囲の下限近傍になると、オーステナイトが不安定
になる。これを防ぐためにはＣ，Ｍｎ含有量は２０×Ｃ
＋Ｍｎ≧２４％を満足する量とする必要がある。
Ｐ：
ＰはＳＲにおける６００〜７００”Ｃの加熱時にオース
テナイト粒界に移動、偏析し５粒界脆化を促進するため
、低く抑える必要があるが、経済性を考慮して、Ｐ含有
量は０．０３０％以下に抑制する。
Ｓ：
Ｓは鋼の熱間加工性、延性、靭性を劣化させる有害な元
素であり、Ｐと同様、極力低く抑える必要があるが、経
済性を考慮して、Ｓ含有量は０．０１５％以下に抑制す
る。
ＭＯ＝
ＭＯは本発明においてＢと並んで非常に゛重要な元素で
あるｅＭｏはオーステナイト組織の安定化と高強度化に
有効であるばかりでなく、耐ＳＲ脆化特性の改善にも大
きな効果を有する。すなわち、第１図は０．６％Ｃ−１
５％Ｍ ｎｆＲをベースにして、シャルビ衝撃特性（ｖ
Ｅ ｏ）に及ぼすＭｏ添加と熱処理（ＳＲ処理）温度
の影響を示したものであり、同図より、ＭＯ無添加鋼は
６００〜８００″ＣＸ２ｈｒの加熱、炉冷により圧延ま
ま材と比較してｖＥｏが１／３以下に低下するが、Ｍｏ
の添加により脆化量は大幅に低減されていることがわか
る。このような効果はＭｏ含有量が０．０５％未満では
発現せず、また２、００％を超える添加はこれらの効果
が飽和すると同時に経済性を損なう。したがって。
Ｍｏ含有量は０．０５〜２．００％の範囲とする。
Ｂ：
Ｂ“も本発明においてＭｏと並んで重要な元素である。
第２図は０．６％Ｃ−１５％Ｍｎ鋼をベースにしてシャ
ルビ衝撃特性（Ｖ Ｅ ｏ）に及ぼすＢ添加と熱処理（
ＳＲ処理）温度の影響を示したものである。
同図より、ＭＯはどではないが、Ｂの添加により、６０
０〜８００℃Ｘ２ｈｒ加熱、炉冷後の靭性は向上するこ
とがわかる。このような効果を得るためには、Ｂは０．
０００５％以上の添加が必要であり、しかし、０．００
５０％を超える添加はこの効果が飽和してしまうばかり
でなく、却って粒界析出物を多くし、靭性を劣化させる
。そのため。
Ｂ含有量は０．０００５〜０．００５０％の範囲とする
。
なお、第３図は０．６％Ｃ−１５％Ｍｎ鋼をベースにし
て、ＭｏとＢの複合添加の効果を示したものであり、同
図より、Ｍｏ、Ｈの複合添加鋼の靭性改善量はＭｏ、Ｈ
の単独添加鋼のそれぞれの靭性改善量を加算した値を大
幅に上まわっており、複合添加の効果が顕著であること
がわかる。
本発明においては、以上の元素を必須成分とするが、以
下に示す元素を必要に応じて適量を添加し或いは規制す
る。
Ｓｎ、Ｓｂ、Ａｓ：
Ｓｎ、Ｓｂ及びＡｓは共にＳＲ中に粒界に移動。
偏析し１粒界脆化をもたらす元素であり、極力低減する
ことが望ましいが、経済性を考慮し、Ｓｎ、ｓｂ及びＡ
ｓの総合有量で０．０２０％以下に規制する。
Ｎｉ、Ｃｒの１種又は２種：
Ｎｉはオーステナイトの安定化や靭性の向上に有効であ
り、必要に応じて添加される。しかし。
０．１０％未満の添加ではこの効果は少なく、また３、
００％を超えると経済性を損なうため、Ｎｉ含有量は０
．１０〜３．００％の範囲とする。
また、Ｃｒはオーステナイトを安定化させると共に高強
度化に有効であり、必要に応じて添加される。しかし、
０．１０％未満の添加ではかへる効果は少なく、また８
、００％を超えるとδフェライトを生成し易くなり、靭
性と磁気特性を低下させる。したがって、Ｃｒ含有量は
０．１０〜８゜００％の範囲とする。
但し、Ｎｉ及びＣｒを添加する場合には、それらの１種
又は２種を添加すれば足りる。
次に本発明の製造条件について説明する。
上記化学成分を有する鋼は、常法により溶製して鋳造さ
れるが、得られる鋳塊又は鋼片を熱間圧延するに当って
、加熱温度、圧延仕上温度、圧延後の冷却条件を規制す
ることにより、更に優れた機械的性質が得られることが
判明した。
まず、加熱温度に関しては、１２５０℃を超えると高温
延性が劣化し、熱間割れが発生し易くなるため、加熱温
度は１２５０’Ｃ以下とする。しかし、１０５０℃未満
の加熱温度になると、析出している炭窒化物の固溶が十
分でなく、特に靭性の劣化を招くばかりでなく、後述す
る仕上温度８゜０℃以上の確保が難しくなる。したがっ
て、加熱温度は１０５０〜１２５０℃とする。
圧延仕上温度に関しては、第４図に示すように、仕上温
度が低下するに従って耐力（ＹＳ）、引張強さ（ＴＳ）
は上昇するものの、靭性（ＶＦ６）の劣化が大きくなり
、特に仕上温度が７５０℃程度以下になるとｖＥｏがｌ
ｏｋｇｆ／ｍ■２以下となることがわかる。したがって
、圧延仕上温度は少なくとも８００℃以上に制御する必
要がある。なお、第４図は０．２３％Ｃ−２４，６％Ｍ
ｎ−０，３５％Ｍｏ−０．００１０％Ｂ＃ｌｌを１２０
０℃に加熱後、図示の仕上温度で圧延を行って板厚２５
ｍｍとし、圧延後空冷した例である。
更に、圧延後の冷却条件に関しては、第５図に圧延後の
７５０〜５５０℃の平均冷却速度と強度、靭性の関係を
示すように、平均冷却速度が大きくなるにつれて、耐力
、引張強さが上昇する傾向にある。また、靭性は１℃／
ｓｅｅ以上の冷却速度において高位に安定しているが、
それ未満の冷却速度では劣化の傾向が認められる。なお
、第５図は第４図に示した例の場合と同じ組成の鋼を、
１２゜０℃に加熱後、仕上温度９００℃で圧延を行って
板厚２５ｍｍとし、圧延後図示の冷却速度で冷却した例
である。
第６図は、第５図に示した圧延まま材と、それに６２５
℃Ｘ２ｈｒのＳＲ処理を施した後のＳＲ処理材について
、圧延後の７５０〜５５０’Ｃの平均冷却速度と靭性の
関係を示したものであるが、圧延後７５０〜５５０℃の
範囲の平均冷却速度が１’Ｃ／ｓｅｃ以上の鋼板の場合
は、ＳＲ処理材のｖＥ。
の低下は小さいが、それ未満の冷却速度による鋼板の場
合はＳＲ処理材のｖＥｏの劣化が大きくなることを示し
ている。
以上の結果から、圧延後の７５０〜５５０℃の温度領域
における平均冷却速度は１℃／ｓｅｃ以上とする。
上記化学成分を有し前記製造条件で得られる鋼板は、溶
接後或いは冷間加工後に６００〜７００℃でのＳＲが施
されても、脆化が非常に小さい。
なお、ＳＲは厳密に６００〜７００℃で実施される場合
のみに限られず、要は、かＮる温度域レベルで残留応力
除去を目的とするＳＲであれば上記効果が得られるので
あり、特にこの温度域６００〜７００℃でのＳＲの場合
に効果が顕著である。
次に本発明の実施例を示すが、本発明はこれら実施例に
よって何ら制限されるものではなく、更に前述の実験例
も実施例足り得ることは云うまでもない。
（実施例）
第１表に示す化学成分を有する鋼を４０キロ高周波炉で
溶解し、その後、同表に示す種々の条件で熱間圧延を行
い、板厚２０ｍ朧、２５ｍｍとした。
それらの圧延まま鋼板と、６２５℃Ｘ２ｈｒのＳＲを施
した鋼板について、引張試験と、２ｍ＋ｓＶシャルビ衝
撃試験を実施すると共に透磁率を測定した。それらの結
果を第２表に併記する。
第２表において、Ａ材、Ｂ材、Ｃ材は同−鋼種材である
が、Ｃ材（比較例）は、圧延後の冷却速度が小さく本発
明範囲外であるため、本発明例のＡ材、Ｂ材と比較して
、ＳＲ後の強度、靭性とも低くなっている。
同様のことがＤ材（本発明例）とＨ材（比較例）、Ｆ（
本発明例）材とＧ材（比較例）、Ｈ材及び丁付（本発明
例）とＪ材（比較例）においても云える。
一方、に材（比較例）はＭｏを含んでいないため、ＳＲ
後の延性、靭性の劣化が大きい。
また、比較例のＨ材とＭ材はＭｏ１．Ｂとも含有してお
らず、本発明の製造条件を適用しても、ＳＲ後の延性、
靭性の劣化が大きいことがわかる。(Industrial Application Field) The present invention relates to a nuclear fusion reactor and linear motor power track equipment. Manufacture of high Mn nonmagnetic steel suitable for nonmagnetic structural steel used in various generators, etc., especially for members that are subjected to stress relief annealing at 600 to 7°C after welding or cold working. It is about the method. (Conventional technology and issues to be solved) High Mn nonmagnetic steel has higher strength, superior magnetic properties, and lower energy consumption than austenitic stainless steel, which is a typical conventional nonmagnetic steel. Since then, its use has been increasing year by year, replacing austenitic stainless steel. However, conventional high Mn nonmagnetic steel has 1.0% C-
13%Mn steel, 0.45%C-18%Mn-5%Cr
Because the C content is relatively high, as typified by steel, 60
When heated to 0 to 700°C, ductility and toughness deteriorate due to precipitation of carbides. Therefore, if residual stress relief treatment is required after welding or cold working, stress relief annealing (S) in such a temperature range is recommended.
There is a problem that R) cannot be implemented. In other words, in SR after welding or cold working, methods such as avoiding this temperature range and processing at a high temperature of 900 to 1100'C, or changing cold working to hot working, etc. This is the reality. However, such countermeasures not only impair economic efficiency but also have the problem of reducing the strength of the steel material. In view of the above-mentioned current situation, it is an object of the present invention to provide high-Mn non-magnetic steel with a high
An object of the present invention is to provide a method for producing a high-Mn nonmagnetic steel that has good mechanical properties even after stress relief annealing. (Means for Solving the Problems) In order to achieve the above object, the present inventor has hereby accomplished the present invention as a result of extensive research into the chemical composition and manufacturing conditions of high Mn nonmagnetic steel. . That is, in the present invention, C: 0.10 to 0.70%, Si
:0.10~1.50%, Mn:10~30%, P:0
．． 030% or less, s:o, ol 5% or less, Mo:O. 05-2.00% and B:O, OOO5-0.0050
%, and satisfies 20×C+Mn≧24%,
If necessary, further add Sn+Sb+As in a total amount of 0.0
Ni: 0.10-3
．． 00% and Cr: 0.10 to 8.00% or 2
Steel containing seeds and the remainder being iron, 1050 to 125
After heating to 0°C, hot rolling is carried out with the finishing temperature controlled at 800°C or higher, and in the subsequent cooling process, at least 7
A method for producing a high-Mn nonmagnetic steel having excellent SR embrittlement resistance, high strength, and high toughness, characterized by cooling in a temperature range of 50 to 550°C at a cooling rate of 1'C/see or more. This is a summary. The present invention will be explained in more detail below. (Structure of the Invention) First, the reasons for limiting the chemical components in the present invention are as follows. C: C is an element effective in stabilizing austenite and improving its strength. However, if it is less than 0.10%, it is necessary to add large amounts of elements such as Mn, Ni, Cr, Mo, etc. to stabilize austenite and ensure strength, which greatly impairs economic efficiency. Moreover, if the content exceeds 0.70%, hot workability and machinability will deteriorate. Therefore, C
The content is in the range of 0.10 to 0.70%. Si: SL has a deoxidizing effect during steel melting and is effective in improving strength, so 0.10% or more is added. However, 1
．． Adding more than 50% will impair hot workability. Therefore, the Si content is 0.10-1.50%
The range shall be . Mrl: Mn is an important austenite-forming element along with C in the steel of the present invention, and must be added in an amount of 10% or more to stabilize nonmagnetism. However, if the content exceeds 30%, hot workability deteriorates significantly. Therefore, the Mn content is in the range of 10 to 30%. However, in the steel of the present invention, C and Mn basically stabilize the austenite and ensure nonmagnetism, but when both C and Mn are near the lower limit of the above range, the austenite becomes unstable. To prevent this, the C and Mn content should be 20×C.
It is necessary to set the amount to satisfy +Mn≧24%. P: P moves to and segregates at austenite grain boundaries during heating at 600 to 700"C in SR and promotes grain boundary embrittlement, so it is necessary to keep it low. However, considering economic efficiency, the P content is Suppress it to 0.030% or less. S: S is a harmful element that deteriorates the hot workability, ductility, and toughness of steel, and like P, it is necessary to keep it as low as possible, but considering economic efficiency, , the S content is suppressed to 0.015% or less. MO = MO is a very important element along with B in the present invention. eMo is effective in stabilizing the austenite structure and increasing its strength. 0.6% C-1
Based on 5% M nfR, Charby impact characteristics (v
This figure shows the influence of Mo addition and heat treatment (SR treatment) temperature on E Although vEo decreases to 1/3 or less, Mo
It can be seen that the amount of embrittlement is significantly reduced by adding . Such effects will not be exhibited if the Mo content is less than 0.05%, and if it is added in excess of 2,00%, these effects will be saturated and at the same time the economic efficiency will be impaired. therefore. The Mo content is in the range of 0.05 to 2.00%. B: B'' is also an important element in the present invention along with Mo. Figure 2 shows the effect of B addition and heat treatment on Charvy impact properties (VEo) based on 0.6%C-15%Mn steel. (
SR treatment) shows the influence of temperature. From the same figure, MO is not the same, but by adding B, 60
It can be seen that the toughness is improved after heating at 0 to 800°C for 2 hours and cooling in the furnace. To obtain such an effect, B must be 0.
It is necessary to add 0.005% or more, but 0.00% or more is required.
Addition of more than 50% not only saturates this effect, but also increases grain boundary precipitates and deteriorates toughness. Therefore. The B content is in the range of 0.0005 to 0.0050%. Furthermore, Figure 3 shows the effect of combined addition of Mo and B based on 0.6%C-15%Mn steel, and from the same figure, the toughness improvement of steel with combined addition of Mo and H is shown. The amount is Mo, H
This significantly exceeds the value obtained by adding up the toughness improvement amount of each individual addition steel, and it can be seen that the effect of the combined addition is remarkable. In the present invention, the above elements are essential components, but the following elements may be added or controlled in appropriate amounts as necessary. Sn, Sb, As: Both Sn, Sb and As migrate to grain boundaries during SR. It is an element that segregates and causes grain boundary embrittlement, and it is desirable to reduce it as much as possible, but considering economic efficiency, Sn, sb and A
The total amount of s is regulated to 0.020% or less. One or both of Ni and Cr: Ni is effective in stabilizing austenite and improving toughness, and is added as necessary. but. This effect is small when less than 0.10% is added, and 3.
If the Ni content exceeds 0.00%, it will impair economic efficiency, so the Ni content should be set to 0.
．． The range is 10% to 3.00%. Further, Cr is effective in stabilizing austenite and increasing its strength, and is added as necessary. but,
Addition of less than 0.10% has little effect on softening, and 8
, 00%, it becomes easy to generate δ ferrite, which deteriorates toughness and magnetic properties. Therefore, the Cr content is in the range of 0.10 to 8.00%. However, when adding Ni and Cr, it is sufficient to add one or two of them. Next, the manufacturing conditions of the present invention will be explained. Steel having the above chemical composition is melted and cast using conventional methods, but when hot rolling the resulting ingot or billet, the heating temperature, rolling finishing temperature, and post-rolling cooling conditions are regulated. It has been found that even better mechanical properties can be obtained by doing so. First, regarding the heating temperature, if it exceeds 1250°C, the high-temperature ductility deteriorates and hot cracking is likely to occur, so the heating temperature is set to 1250'C or less. However, if the heating temperature is lower than 1050℃, the solid solution of the precipitated carbonitrides will not be sufficient, which will not only cause deterioration of toughness, but also make it difficult to maintain a finishing temperature of 8.0℃ or higher, which will be described later. . Therefore, the heating temperature is 1050 to 1250°C. Regarding the rolling finishing temperature, as shown in Figure 4, as the finishing temperature decreases, the proof stress (YS) and tensile strength (TS) decrease.
Although this increases, the deterioration of toughness (VF6) increases, and especially when the finishing temperature is below about 750℃, vEo decreases.
It can be seen that the value is less than okgf/m2. Therefore, it is necessary to control the finishing rolling temperature to at least 800°C or higher. In addition, Fig. 4 shows 0.23%C-24.6%M
n-0,35%Mo-0.0010%B#ll 120
After heating to 0℃, rolling is performed at the finishing temperature shown in the figure to obtain a plate thickness of 25.
This is an example in which the steel sheet was rolled and cooled in air after rolling. Furthermore, regarding the cooling conditions after rolling, as shown in Figure 5, which shows the relationship between the average cooling rate of 750 to 550°C after rolling, strength, and toughness, as the average cooling rate increases, the yield strength and tensile strength decrease. It is on the rise. In addition, the toughness is 1℃/
Although it is highly stable at cooling rates higher than see,
If the cooling rate is lower than that, there is a tendency for deterioration. In addition, Fig. 5 shows steel with the same composition as in the example shown in Fig. 4.
This is an example in which the sheet was heated to 12.degree. C. and then rolled at a finishing temperature of 900.degree. C. to a plate thickness of 25 mm, and after rolling was cooled at the cooling rate shown. Figure 6 shows the as-rolled material shown in Figure 5 and the 625
This shows the relationship between the average cooling rate of 750 to 550'C after rolling and toughness for the SR treated material after SR treatment of ℃ x 2 hours. For steel plates whose speed is 1'C/sec or more, vE of SR treated material. Although the decrease in vEo of the SR-treated material is small, the deterioration of vEo of the SR-treated material becomes large in the case of a steel plate with a cooling rate lower than that. From the above results, the average cooling rate in the temperature range of 750 to 550°C after rolling is set to be 1°C/sec or more. A steel plate having the above chemical composition and obtained under the above manufacturing conditions has very little embrittlement even if it is subjected to SR at 600 to 700°C after welding or cold working. Note that SR is not limited to strictly being carried out at 600 to 700°C; the point is that the above effects can be obtained if the SR is aimed at removing residual stress at a temperature range of 600 to 700°C. The effect is remarkable in the case of SR in this temperature range of 600 to 700°C. Next, examples of the present invention will be shown, but the present invention is not limited to these examples in any way, and it goes without saying that the above-mentioned experimental examples can also be considered as examples. (Example) Steel having the chemical composition shown in Table 1 was melted in a 40 kg high frequency furnace, and then hot rolled under various conditions shown in the same table to obtain a plate thickness of 20 m and 25 mm. A tensile test and a 2m+sV Charby impact test were conducted on the as-rolled steel sheets and the steel sheets subjected to SR at 625° C. for 2 hours, and the magnetic permeability was measured. The results are also listed in Table 2. In Table 2, material A, material B, and material C are the same steel grade materials, but material C (comparative example) has a small cooling rate after rolling and is outside the scope of the present invention. Compared with Material and Material B, both the strength and toughness after SR are lower. The same thing applies to material D (invention example), material H (comparative example), and material F (
The same can be said for material (example of the present invention) and material G (comparative example), material H and tabling (example of the invention), and material J (comparative example). On the other hand, the Ni material (comparative example) does not contain Mo, so the SR
The subsequent deterioration of ductility and toughness is significant. Moreover, the H material and M material of the comparative example are Mo1. Even if the manufacturing conditions of the present invention are applied, the ductility after SR,
It can be seen that the toughness deteriorates significantly.
（発明の効果）
以上詳述したように、本発明によれば、高Ｍｎ非磁性鋼
において、Ｃ含有量を比較的低くし、特にＭｏとＢを複
合添加する等により化学成分を適切に調整すると共に、
製造条件を規制したので、６００〜７００’Ｃでの応力
除力焼鈍に供しても、高Ｍｎ非磁性鋼の有する基本的特
性を損なうことなく、耐ＳＲ脆化特性が著しく改善され
た優れた機械的性質を有する高Ｍｎ非磁性鋼を得ること
ができる。したがって、溶接後或いは冷間加工後に６０
０〜７００℃での応力除力焼鈍が行われる部材に好適で
ある。(Effects of the Invention) As detailed above, according to the present invention, in high Mn nonmagnetic steel, the C content is made relatively low, and the chemical composition is appropriately adjusted, particularly by adding Mo and B in combination. At the same time,
Since the manufacturing conditions were regulated, even when subjected to stress relief annealing at 600 to 700'C, the basic properties of high Mn nonmagnetic steel were not impaired, and the SR embrittlement resistance was significantly improved. A high Mn non-magnetic steel with mechanical properties can be obtained. Therefore, after welding or cold working, the
It is suitable for members subjected to stress relief annealing at 0 to 700°C.
第１図はシャルビ衝撃特性に及ぼすＭＯ添加と熱処理（
ＳＲ処理）条件の影響を示す図。
第２図はシャルビ衝撃特性に及ぼすＢ添加と熱処理（Ｓ
Ｒ処理）条件の影響を示す図、第３図はシャルビ衝撃特
性に及ぼすＭＯｌＢの複合添加と熱処理（ＳＲ処理）条
件の影響を示す図、第４図は圧延仕上温度と耐力、引張
強さ、及び靭性の関係を示す図、
第５図は圧延後の７５０〜５５０℃における平均冷却速
度と耐力、引張強さ及び靭性の関係を示す図、
第６図は圧延後の７５０〜５５０’Ｃにおける平均冷却
速度と靭性の関係を圧延まま材とＳＲ処理材について示
す図である。Figure 1 shows the effect of MO addition and heat treatment (
SR processing) A diagram showing the influence of conditions. Figure 2 shows the effect of B addition and heat treatment (S
Figure 3 is a diagram showing the influence of combined addition of MOIB and heat treatment (SR treatment) conditions on Charvy impact properties, Figure 4 is a diagram showing the influence of finishing rolling temperature, yield strength, tensile strength, Figure 5 is a diagram showing the relationship between average cooling rate and yield strength, tensile strength and toughness at 750-550'C after rolling, Figure 6 is a diagram showing the relationship between average cooling rate at 750-550'C after rolling, tensile strength and toughness, and Figure 6 is a diagram showing the relationship between average cooling rate at 750-550'C after rolling. FIG. 3 is a diagram showing the relationship between average cooling rate and toughness for as-rolled material and SR-treated material.
Claims (3)
０％、Ｐ：０．０３０％以下、Ｓ：０．０１５％以下、
Ｍｏ：０．０５〜２．００％及びＢ：０．０００５〜０
． ００５０％を含有し、かつ、２０×Ｃ＋Ｍｎ≧２４％を
満足し、残部が鉄よりなる鋼を、１０５０〜１２５０℃
に加熱後、仕上温度を８００℃以上に制御した熱間圧延
を行い、その後の冷却過程において、少なくとも７５０
〜５５０℃の温度領域を１℃／ｓｅｃ以上の冷却速度で
冷却することを特徴とする耐ＳＲ脆化特性が優れ、且つ
高強度、高靭性を有する高Ｍｎ非磁性鋼の製造方法。(1) In weight% (the same applies hereinafter), C: 0.10 to 0. 70%, Si: 0.10-1.50%, Mn: 10-3
0%, P: 0.030% or less, S: 0.015% or less,
Mo: 0.05-2.00% and B: 0.0005-0
．． 0050% and satisfies 20×C+Mn≧24%, with the remainder being iron, at 1050 to 1250°C.
After heating, hot rolling is carried out with the finishing temperature controlled at 800°C or higher, and in the subsequent cooling process, at least 750°C
A method for manufacturing a high-Mn nonmagnetic steel having excellent SR embrittlement resistance, high strength, and high toughness, characterized by cooling in a temperature range of ~550°C at a cooling rate of 1°C/sec or more.
２０％以下に規制したものである請求項１に記載の方法
。(2) The steel further contains Sn+Sb+As in a total amount of 0.0
The method according to claim 1, wherein the amount is regulated to 20% or less.
Ｃｒ：０．１０〜８．００％の１種又は２種を含有する
ものである請求項１又は２に記載の方法。(3) The method according to claim 1 or 2, wherein the steel further contains one or both of Ni: 0.10 to 3.00% and Cr: 0.10 to 8.00%. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1147367A JP2533935B2 (en) | 1989-06-10 | 1989-06-10 | Method for producing high Mn non-magnetic steel having excellent SR embrittlement resistance, high strength and high toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1147367A JP2533935B2 (en) | 1989-06-10 | 1989-06-10 | Method for producing high Mn non-magnetic steel having excellent SR embrittlement resistance, high strength and high toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0313525A true JPH0313525A (en) | 1991-01-22 |
| JP2533935B2 JP2533935B2 (en) | 1996-09-11 |
Family
ID=15428619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1147367A Expired - Lifetime JP2533935B2 (en) | 1989-06-10 | 1989-06-10 | Method for producing high Mn non-magnetic steel having excellent SR embrittlement resistance, high strength and high toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2533935B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2878257A1 (en) * | 2004-11-24 | 2006-05-26 | Usinor Sa | PROCESS FOR MANUFACTURING AUSTENITIC STEEL SHEET, FER-CARBON-MANGANIZED WITH VERY HIGH RESISTANCE AND ELONGATION CHARACTERISTICS, AND EXCELLENT HOMOGENEITY |
| CN104160058A (en) * | 2012-01-25 | 2014-11-19 | 塔塔钢铁英国有限公司 | Steel for producing parts for railway, railway crossings and switches and method for producing said parts |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4044483B2 (en) | 2003-04-25 | 2008-02-06 | 新日本製鐵株式会社 | Bonding structure of structures using gusset plates and buildings |
-
1989
- 1989-06-10 JP JP1147367A patent/JP2533935B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2878257A1 (en) * | 2004-11-24 | 2006-05-26 | Usinor Sa | PROCESS FOR MANUFACTURING AUSTENITIC STEEL SHEET, FER-CARBON-MANGANIZED WITH VERY HIGH RESISTANCE AND ELONGATION CHARACTERISTICS, AND EXCELLENT HOMOGENEITY |
| WO2006056670A2 (en) * | 2004-11-24 | 2006-06-01 | Arcelor France | Method of producing austentic iron/carbon/manganese steel sheets having very high strength and elongation characteristics and excellent homogeneity |
| WO2006056670A3 (en) * | 2004-11-24 | 2007-07-05 | Arcelor France | Method of producing austentic iron/carbon/manganese steel sheets having very high strength and elongation characteristics and excellent homogeneity |
| US7794552B2 (en) | 2004-11-24 | 2010-09-14 | Arcelor France | Method of producing austenitic iron/carbon/manganese steel sheets having very high strength and elongation characteristics and excellent homogeneity |
| CN104160058A (en) * | 2012-01-25 | 2014-11-19 | 塔塔钢铁英国有限公司 | Steel for producing parts for railway, railway crossings and switches and method for producing said parts |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2533935B2 (en) | 1996-09-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102367540B (en) | Deep sea pipeline steel produced based on steckel mill and preparation method thereof | |
| CN114959509B (en) | 690 MPa-grade high-toughness steel plate and production method thereof | |
| JPS605647B2 (en) | Method for manufacturing boron-containing non-thermal high tensile strength steel with excellent low-temperature toughness and weldability | |
| JPS6053726B2 (en) | Method for manufacturing austenitic stainless steel sheets and steel strips | |
| CN113166901A (en) | Chromium-molybdenum steel plate with excellent creep strength and preparation method thereof | |
| JPH0320408A (en) | Production of high tensile steel stock excellent in toughness at low temperature | |
| JPH01159356A (en) | High tension steel having superior tougeness at weld heat-affected zone | |
| JPS6054374B2 (en) | Method for manufacturing austenitic steel plates and steel strips | |
| JPH0313525A (en) | Production of high-mn nonmagnetic steel having excellent sr brittle resistant characteristic, high strength and high toughness | |
| JPS5831069A (en) | Thick high tensile steel plate with high strength and toughness | |
| JPS63259022A (en) | Manufacture of high-mn nonmagnetic steel excellent in stability of magnetic permeability | |
| JPH11131177A (en) | Steel plate for medium-or ordinary-temperature pressure vessel, capable of omitting post weld heat treatment, and its production | |
| JPH03249128A (en) | Production of tough thick steel plate | |
| JPH04272130A (en) | Production of high mn nonmagnetic steel having superior drillability | |
| JPH01172516A (en) | Manufacture of acicular ferritic stainless steel having excellent stress corrosive cracking resistance | |
| KR20140030465A (en) | Steel plate and method for manufacturing of the same | |
| JPH05295432A (en) | Production of steel plate having high strength and high toughness by online thermomechanical treatment | |
| JPH1121625A (en) | Production of thick steel plate excellent in strength and toughness | |
| JPH02190445A (en) | High-mn nonmagnetic steel excellent in sr embrittlement-resisting property | |
| JPS61127814A (en) | Manufacture of high tension steel plate having excellent low-temperature toughness | |
| JPH0366367B2 (en) | ||
| JPS63250416A (en) | Manufacture of steel material excellent in stress corrosion cracking resistance and having low yield ratio in sulfide-rich circumstances | |
| JPS62256916A (en) | Production of low-temperature extra-thick steel plate having excellent uniformity in thickness direction | |
| JPH04354856A (en) | Ferritic heat resistant steel excellent in touchness and creep strength and its production | |
| JPH0232325B2 (en) | ITAATSUHOKOTOKUSEINOSUGURETAHICHOSHITSUKOCHORYOKUKONOSEIZOHOHO |