JPH0781164B2 - Method for manufacturing high-strength and high-toughness steel sheet - Google Patents
Method for manufacturing high-strength and high-toughness steel sheetInfo
- Publication number
- JPH0781164B2 JPH0781164B2 JP61097849A JP9784986A JPH0781164B2 JP H0781164 B2 JPH0781164 B2 JP H0781164B2 JP 61097849 A JP61097849 A JP 61097849A JP 9784986 A JP9784986 A JP 9784986A JP H0781164 B2 JPH0781164 B2 JP H0781164B2
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- toughness
- strength
- steel
- cooling
- 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.)
- Expired - Fee Related
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 53
- 239000010959 steel Substances 0.000 title claims description 53
- 238000004519 manufacturing process Methods 0.000 title claims description 21
- 238000000034 method Methods 0.000 title description 9
- 238000005096 rolling process Methods 0.000 claims description 88
- 238000001816 cooling Methods 0.000 claims description 35
- 238000010438 heat treatment Methods 0.000 claims description 13
- 230000032683 aging Effects 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 229910052758 niobium Inorganic materials 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 27
- 238000001953 recrystallisation Methods 0.000 description 27
- 238000005728 strengthening Methods 0.000 description 14
- 238000001556 precipitation Methods 0.000 description 10
- 229910001566 austenite Inorganic materials 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 230000009466 transformation Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000005275 alloying Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 230000003749 cleanliness Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- -1 71 (1985) Chemical compound 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- RMLPZKRPSQVRAB-UHFFFAOYSA-N tris(3-methylphenyl) phosphate Chemical compound CC1=CC=CC(OP(=O)(OC=2C=C(C)C=CC=2)OC=2C=C(C)C=CC=2)=C1 RMLPZKRPSQVRAB-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Description
【発明の詳細な説明】 「発明の目的」 本発明は高張力高靭性鋼板の製造方法に係り、溶接施工
性の優れ、YS≧60kgf/mm2、TS≧65kgf/mm2およびvTrs≦
−120℃を何れも満足した高強度、高靭性鋼板を圧延能
率を低下させることなく高い生産性を維持し低コスト且
つ的確に製造することのできる方法を提供しようとする
ものである。DETAILED DESCRIPTION OF THE INVENTION “Object of the Invention” The present invention relates to a method for producing a high-strength and high-toughness steel sheet, which has excellent weldability, YS ≧ 60 kgf / mm 2 , TS ≧ 65 kgf / mm 2 and vTrs ≦.
An object of the present invention is to provide a method capable of accurately manufacturing a high-strength, high-toughness steel sheet satisfying all of −120 ° C. while maintaining high productivity without lowering rolling efficiency and at low cost.
産業上の利用分野 溶接施工を受ける高張力高靭性構造用鋼の製造技術。Industrial field Manufacturing technology for high-strength, high-toughness structural steel subjected to welding.
従来の技術 溶接施工性を良好とするためにCuの時効析出強化を利用
した鋼の代表例としてはASTMに規格化されているA710あ
るいはA736鋼が挙げられる。これらは1.0〜1.3％のCuを
含み、主に焼ならしあるいは焼入れ後に時効することに
よって所要の強度・靭性を付与するものである。本鋼種
は比較的低い炭素当量の成分であるため優れた溶接性を
示すが、高い靭性を付与するためには焼ならしあるいは
焼入れといった熱処理が必要であり、熱処理コストがか
かり工程が多くなった。そこでこのような問題を改善す
るためCuの時効析出強化に対し制御圧延・冷却冷却（Th
ermomechanical Control Process）を利用したCu添加高
張力鋼板が提案されている。その特徴とするところは、
制御圧延あるいは制御冷却を実施し、これによって強度
・靭性等の特性を付与し熱処理工程を省略することにあ
る。Conventional technology A710 or A736 steel, which is standardized in ASTM, is a typical example of steel that uses age precipitation strengthening of Cu to improve weldability. These contain 1.0 to 1.3% of Cu, and impart the required strength and toughness mainly by aging after normalizing or quenching. Since this steel type has a relatively low carbon equivalent component, it exhibits excellent weldability, but heat treatment such as normalizing or quenching is required to impart high toughness, and the heat treatment cost increases the number of processes. . Therefore, in order to improve such problems, controlled rolling, cooling and cooling (Th
A Cu-added high-strength steel sheet using an ermomechanical control process) has been proposed. The feature is that
The purpose of this is to carry out controlled rolling or controlled cooling, thereby imparting properties such as strength and toughness and omitting the heat treatment step.
このような考え方に基づいたものとして、0.06％Ｃ−1.
40％Mn−1.2％Cu−0.03％Nb鋼に制御圧延・制御冷却を
実施したもの〔鉄と鋼、71（1985）、S1507〕が発表さ
れている。Based on this idea, 0.06% C-1.
Controlled rolling and controlled cooling of 40% Mn-1.2% Cu-0.03% Nb steel [Iron and Steel, 71 (1985), S1507] have been announced.
発明が解決しようとする問題点 しかし、前記したような従来のTMCPを利用するCu析出強
化鋼においては靭性確保のため圧延工程においてオース
テナイト低温域で圧延を仕上げることが必要で、比較的
厳しい制御圧延の実施を必須要件とし、このため以下に
列挙する問題点がある。Problems to be Solved by the Invention However, in the Cu precipitation strengthened steel utilizing the conventional TMCP as described above, it is necessary to finish rolling in the austenite low temperature region in the rolling process in order to secure toughness, and relatively strict control rolling Is an essential requirement, and there are problems listed below.
制御圧延に伴う圧延能率の低下 圧延荷重の増加による圧延機の負荷増大。 Reduction of rolling efficiency due to controlled rolling Increase of rolling mill load due to increase of rolling load.
従って高コスト化も避け得ない。Therefore, cost increase is inevitable.
「発明の構成」 問題点を解決するための手段 C:0.01〜0.10wt％、Si:0.01〜0.80wt％、Mn:0.20〜2.0w
t％、Cu:0.6〜1.5wt％、Nb:0.005〜0.060wt％、sol.Al:
0.005〜0.080wt％ を含有し、残部がFeおよび不可避的不純物からなる鋼を
950〜1250℃に加熱してから900〜1000℃の温度範囲で50
％以上の圧延を施し、800℃を越え900℃未満で最終仕上
げ圧延をなし、その後直ちに２〜50℃/secの冷却速度で
550℃以下の温度域まで冷却し、次いで時効処理を行う
ことを特徴とする高張力高靭性鋼板の製造方法、およ
び、 C:0.01〜0.10wt％、Si:0.01〜0.80wt％、Mn:0.20〜2.0w
t％、Cu:0.6〜1.5wt％、Nb:0.005〜0.060wt％、sol.Al:
0.005〜0.080wt％ を含有すると共に、 Ni:0.05〜0.8wt％、Cr:0.05〜1.5wt％、Mo:0.03〜0.5wt
％、V:0.01〜0.20wt％、Ti:0.03〜0.10wt％、B:0.0003
〜0.003wt％ の何れか１種または２種以上を含有し、残部がFeおよび
不可避的不純物からなる鋼を950〜1250℃に加熱してか
ら900〜1000℃の温度範囲で50％以上の圧延を施し、800
℃を越え900℃未満で最終仕上げ圧延をなし、その後直
ちに２〜50℃/secの冷却速度で550℃以下の温度域まで
冷却し、次いで時効処理を行うことを特徴とする高張力
高靭性鋼板の製造方法。"Structure of invention" Means for solving problems C: 0.01 to 0.10 wt%, Si: 0.01 to 0.80 wt%, Mn: 0.20 to 2.0w
t%, Cu: 0.6 to 1.5 wt%, Nb: 0.005 to 0.060 wt%, sol.Al:
Steel containing 0.005 to 0.080 wt% with the balance Fe and unavoidable impurities
50 to 900-1000 ℃ temperature range after heating to 950-1250 ℃
% Or more, and finally finish rolling at over 800 ℃ and under 900 ℃, then immediately at a cooling rate of 2-50 ℃ / sec.
A method for producing a high-strength and high-toughness steel sheet characterized by cooling to a temperature range of 550 ° C. or lower and then performing an aging treatment, and C: 0.01 to 0.10 wt%, Si: 0.01 to 0.80 wt%, Mn: 0.20 ~ 2.0w
t%, Cu: 0.6 to 1.5 wt%, Nb: 0.005 to 0.060 wt%, sol.Al:
It contains 0.005-0.080wt%, Ni: 0.05-0.8wt%, Cr: 0.05-1.5wt%, Mo: 0.03-0.5wt%
%, V: 0.01 to 0.20 wt%, Ti: 0.03 to 0.10 wt%, B: 0.0003
~ 0.003 wt% of any one or more of them, the balance of which consists of Fe and unavoidable impurities, the steel is heated to 950 to 1250 ℃, then rolled to more than 50% in the temperature range of 900 to 1000 ℃ Given 800
High-tensile high-toughness steel sheet characterized by performing final finishing rolling at a temperature above 900 ° C and below 900 ° C, immediately thereafter cooling to a temperature range of 550 ° C or less at a cooling rate of 2 to 50 ° C / sec, and then performing an aging treatment. Manufacturing method.
作用 C:0.01％以上、Mn:0.20％以上、Nb:0.005％以上を含有
させることによって強度を向上する。C:0.10％以下、S
i:0.80％以下、Mn:2.0％以下、Nb:0.060％以下、Cu:0.6
0％以上含有させることによって強靭化を図る。またCu
が0.6％以上含有せしめられたことにより熱間加工後の
再結晶抑制効果を得しめ、所要の機械的性質を得るため
の制御圧延条件を大幅に緩和する。Action C: 0.01% or more, Mn: 0.20% or more, Nb: 0.005% or more to improve the strength. C: 0.10% or less, S
i: 0.80% or less, Mn: 2.0% or less, Nb: 0.060% or less, Cu: 0.6
Strengthening is aimed at by containing 0% or more. Also Cu
Is contained in an amount of 0.6% or more, the effect of suppressing recrystallization after hot working is obtained, and the controlled rolling conditions for obtaining the required mechanical properties are greatly relaxed.
Ｃを0.10％以下として溶接性劣化を避けると共に強度確
保のため多量の合金元素を添加する必要がないように
し、Siを0.8％以下として溶接性を良好にする。C is set to 0.10% or less to prevent deterioration of weldability and it is not necessary to add a large amount of alloying elements to secure strength, and Si is set to 0.8% or less to improve weldability.
sol.Alを0.005％以上として脱酸を図り、しかも0.08％
以下として鋼の清浄性を確保する。Deoxidized with sol.Al of 0.005% or more, and 0.08%
Ensure the cleanliness of the steel as follows.
上記基本成分に対しCrを0.05％以上、Moを0.03％、B:0.
0003％以上を含有させることによって焼入れ性を向上
し、加速冷却における強度向上効果を増大し、又Ni0.05
％以上含有させて母材靭性を向上する。Cr is 0.05% or more, Mo is 0.03%, B: 0.
By containing 0003% or more, hardenability is improved, strength improving effect in accelerated cooling is increased, and Ni0.05
% To improve the toughness of the base material.
Ｖを0.01％以上、Tiを0.03％以上を含有させて析出強化
を図る。V is contained in 0.01% or more and Ti is contained in 0.03% or more to enhance precipitation strengthening.
Crが0.80％以下、Moが0.50％以下として経済性を得しめ
る。Economic efficiency can be obtained with Cr of 0.80% or less and Mo of 0.50% or less.
製造プロセスとして950℃以上に加熱することによりNb
の固溶を図ると共に好ましい熱間加工性を得しめ、又12
50℃以下としてオーステナイト粒の粗大化を避ける。Nb by heating above 950 ℃ as a manufacturing process
And the preferable hot workability, and
Avoid coarsening of austenite grains by keeping the temperature below 50 ° C.
900℃〜1000℃で50％以上の第１段圧延をなすことによ
りCuの含有によっても再結晶による細粒化効果を充分に
得しめ、しかも再結晶完了後の粒成長を回避する。By performing 50% or more of the first stage rolling at 900 ° C. to 1000 ° C., the grain refining effect by recrystallization can be sufficiently obtained even by the inclusion of Cu, and the grain growth after the completion of recrystallization is avoided.
800℃〜900℃で第２段圧延し最終仕上げをなすことによ
り変態組織を一層細粒化する。The transformed structure is further refined by rolling in the second stage at 800 ° C to 900 ° C for final finishing.
圧延後直ちに２〜50℃/secの冷却速度で550℃以下まで
冷却することにより変態組織を細粒の低温変態組織主体
として強度、靭性を向上させる。Immediately after rolling, by cooling at a cooling rate of 2 to 50 ° C./sec to 550 ° C. or less, the transformation structure is mainly composed of a low temperature transformation structure of fine grains to improve strength and toughness.
次いで時効処理することにより板厚中心部に到るまで良
好な強度を得しめる。Then, by aging treatment, good strength can be obtained up to the center of the plate thickness.
実施例 上記したような本発明について更に説明すると、従来か
ら靭性の改善を図るため未再結晶域での圧延を強化する
制御圧延技術が発展され、その具体的方法としては特開
昭60−59018に見られるように、例えば800℃以下の累積
圧下を圧延において施す、所謂オーステナイト低温域圧
延が必要とされてきた。つまり圧延による靭性向上に対
しては低温圧延（主に800℃以下）を必須とするのが従
来の考え方であるが、この場合は前述したように圧延能
率面での不利は避け得ない。EXAMPLESTo further explain the present invention as described above, a controlled rolling technique for strengthening rolling in a non-recrystallized region has been developed in order to improve toughness, and a specific method thereof is JP-A-60-59018. As can be seen from the above, a so-called austenite low temperature region rolling, in which a cumulative reduction of 800 ° C. or less is applied in rolling, has been required. In other words, it is a conventional idea that low temperature rolling (mainly 800 ° C. or lower) is indispensable for improving the toughness by rolling, but in this case, the disadvantage in terms of rolling efficiency is unavoidable as described above.
そこで本発明者等は、圧延能率を低下させることなく優
れた鋼板特性を得るための方策をプロセス・成分の改善
という立場から鋭意検討した結果、Cuが鋼の熱間加工後
の再結晶を抑制する性質を有するという全く新規の知見
を初めて見出した。然してこの新規な知見に基づいて圧
延方法と靭性の関連を新たに再検討した結果、Cuを0.6
％以上含む鋼においては、再結晶温度域での圧延及び圧
延後の冷却条件を工夫することによって、所要の機械的
性質を得るための制御圧延条件を従来に比べ大幅に緩和
できることを見出し、これによって圧延能率の大幅向
上、圧延機の寿命向上という多大な利益がもたらされる
のである。Therefore, the inventors of the present invention have diligently studied measures for obtaining excellent steel sheet properties without lowering the rolling efficiency from the standpoint of improving the process and components, and as a result, Cu suppresses recrystallization of steel after hot working. For the first time, a completely new finding that it has the property of However, based on this new finding, a new reexamination of the relationship between rolling method and toughness revealed that Cu was 0.6
% Steel, it was found that by controlling the rolling conditions in the recrystallization temperature range and the cooling conditions after rolling, the controlled rolling conditions for obtaining the required mechanical properties can be significantly relaxed compared with the conventional method. As a result, there are enormous benefits such as a significant improvement in rolling efficiency and a longer rolling mill life.
即ち成分的特徴として0.6％以上のCuを含有させ、更
に製造条件として再結晶温度域である900℃以上の温
度範囲で圧下率50％以上の圧延を実施し、圧延後に加
速冷却を施す、ことを組合わせることによって初めて未
再結晶域での制御圧延条件を緩和させ得るである。That is, 0.6% or more of Cu as a component characteristic is contained, and further rolling is performed at a rolling reduction of 50% or more in a temperature range of 900 ° C. or more which is a recrystallization temperature range as a manufacturing condition, and accelerated cooling is performed after the rolling. The controlled rolling conditions in the unrecrystallized region can be relaxed only by combining the above.
以下に本発明における構成要件についてその仔細を述べ
ると、本発明はまず成分的には0.6％以上1.5％以下のCu
を含有させることを必須の条件としているが、これには
以下に述べる２つの効果がある。即ち第１は時効による
ε−Cuの析出に基づいた強化が図れることであり、第２
の熱間圧延時における再結晶抑制効果に基づいた靭性向
上効果である。つまりCu添加は強度および靭性の両者を
改善することに有効である。The details of the constitutional requirements in the present invention will be described below. The present invention is based on the fact that the composition is 0.6% to 1.5% Cu.
The essential condition is to contain, but this has the following two effects. That is, the first is that strengthening can be achieved based on the precipitation of ε-Cu by aging.
Is an effect of improving toughness based on the effect of suppressing recrystallization during hot rolling. That is, Cu addition is effective in improving both strength and toughness.
また900℃以上の温度域での圧延を規定しているのは、
上述したようにCuが再結晶抑制効果を有するため、従来
の製造条件より高い温度域での圧延を実施しないと再結
晶域での圧延の確保が困難となるためである。再結晶域
での圧延は、一般的に知られているように加熱時の粗粒
オーステナイトを細かくするのに有効であり、再結晶域
圧延の圧下の大小が鋼板の機械的性質、特に靭性と密接
に関係する。Cu添加鋼においては、比較的高い温度領域
での再結晶域圧延が特性向上のために肝要であり、従来
技術はこの点を全く考慮していなかった。In addition, what regulates rolling in the temperature range of 900 ℃ or more,
This is because, as described above, Cu has the effect of suppressing recrystallization, so that it is difficult to secure rolling in the recrystallization region unless rolling is performed in a temperature range higher than the conventional manufacturing conditions. Rolling in the recrystallization region is effective in making coarse-grained austenite fine during heating, as is generally known, and the rolling reduction in the recrystallization region determines the mechanical properties of the steel sheet, particularly toughness and Closely related. In the Cu-added steel, recrystallization zone rolling in a relatively high temperature range is essential for improving the properties, and the prior art did not consider this point at all.
更に圧延後の冷却条件を規定しているのは、主に鋼板強
度の確保を目的としている。圧延後の加速冷却の実施に
より、空冷ままに比べより低い低炭素当量の母材成分の
もとで必要な強度が得られるが、これによって母材靭性
および溶接性の改善も同時にもたらされる。Further, the cooling conditions after rolling are specified mainly for the purpose of ensuring the strength of the steel sheet. By carrying out accelerated cooling after rolling, the required strength can be obtained under a lower carbon equivalent base material component than that in the as-cooled state, but this also brings about an improvement in base material toughness and weldability.
即ち、適量なCuの添加と未再結晶域圧延の前後工程であ
る再結晶域圧延及び圧延後の冷却条件を的確に制御する
ことにより、低温オーステナイト域での制御圧延を緩和
することができ、このことが能率面の改善につながるの
である。That is, by appropriately controlling the cooling conditions after the recrystallization zone rolling and the rolling which are the steps before and after the addition of an appropriate amount of Cu and the non-recrystallization zone rolling, the controlled rolling in the low temperature austenite zone can be relaxed, This leads to improvement in efficiency.
本発明における成分、圧延・冷却条件の限定理由を述べ
ると以下の如くである。The reasons for limiting the components and the rolling / cooling conditions in the present invention are as follows.
0.01≦Ｃ≦0.10％。0.01 ≦ C ≦ 0.10%.
炭素は強度向上に有利な元素であるが、0.10％を超える
と溶接性・靭性を損なうことがあるので上限を0.10％と
した。また0.01％未満では、強度を確保するために多量
の合金元素添加が必要となり経済的に不利となるので下
限を0.01％とした。Carbon is an element that is advantageous for improving strength, but if it exceeds 0.10%, weldability and toughness may be impaired, so the upper limit was made 0.10%. If it is less than 0.01%, a large amount of alloying elements must be added to secure the strength, which is economically disadvantageous, so the lower limit was made 0.01%.
0.01≦Si≦0.80％。0.01 ≦ Si ≦ 0.80%.
Siは脱酸元素および固溶強化元素として有用な元素があ
るが、0.80％を超えると溶接性の劣化および母材靭性の
劣化をもたらすことがあり、上限を0.8％とした。また
0.01％未満では、その効果が期待できないので下限を0.
01％とした。Although Si is useful as a deoxidizing element and a solid solution strengthening element, if it exceeds 0.80%, weldability and base material toughness may deteriorate, so the upper limit was made 0.8%. Also
If it is less than 0.01%, the effect cannot be expected, so the lower limit is 0.
It was set to 01%.
0.20≦Mn≦2.0％。0.20 ≦ Mn ≦ 2.0%.
Mnは比較的経済的に強度向上が図れる元素であるが、2.
0％を超えると溶接性・母材靭性の双方に対し不利とな
ることがあるので、上限を2.0％とした。一方0.2％未満
では、強度確保のため他の合金元素の多量添加が必要と
なり経済的に不利となるので、下限を0.20％とした。Mn is an element whose strength can be improved relatively economically, 2.
If it exceeds 0%, it may be disadvantageous to both weldability and base metal toughness, so the upper limit was made 2.0%. On the other hand, if it is less than 0.2%, a large amount of other alloying elements must be added to secure the strength, which is economically disadvantageous, so the lower limit was made 0.20%.
0.60≦Cu≦1.5％。0.60 ≦ Cu ≦ 1.5%.
Cuの添加は本発明を構成する主要な要件であり、ε−Cu
による時効析出強化およびCuによる再結晶抑制効果を通
じて、鋼板の強靭化に有効に作用するが、0.6％未満で
は所要の析出強化量、再結晶抑制効果が得られず、また
1.5％を超えると強化量が飽和に近づき、添加に見合っ
た特性向上が得られない場合があるので、添加範囲を0.
60≦Cu≦1.5％とした。The addition of Cu is a major requirement that constitutes the present invention, and ε-Cu
Through the effect of aging precipitation strengthening by Cu and the recrystallization suppressing effect by Cu, it effectively acts on the toughness of the steel sheet, but if it is less than 0.6%, the required precipitation strengthening amount and recrystallization suppressing effect cannot be obtained, and
If it exceeds 1.5%, the amount of strengthening will approach saturation, and it may not be possible to obtain the characteristic improvement commensurate with the addition.
60 ≦ Cu ≦ 1.5%.
0.005≦Nb≦0.060％。0.005 ≦ Nb ≦ 0.060%.
Nbは微量添加で析出強化が達成できる元素であり、また
Nb添加は、制御圧延及び加速冷却による機械的性質の向
上効果を一層大きくするが、0.060％を超える添加では
これらの効果がほぼ飽和し、逆に靭性面で不利益となる
ことがあるので上限を0.060％とした。一方、0.005％未
満ではその効果が少ないので下限を0.005％とした。Nb is an element that can achieve precipitation strengthening by adding a trace amount.
Nb addition further enhances the effect of improving mechanical properties by controlled rolling and accelerated cooling, but addition of more than 0.060% almost saturates these effects, and on the contrary, it may be disadvantageous in terms of toughness. Was set to 0.060%. On the other hand, if less than 0.005%, the effect is small, so the lower limit was made 0.005%.
0.005≦sol.Al≦0.080％。0.005 ≦ sol.Al ≦ 0.080%.
Alは、脱酸材として使用されるが、0.005％未満ではそ
の効果が十分でなく、また0.080％を超えると鋼の清浄
性を損なうことがあるので添加範囲を0.005≦sol.Al≦
0.080％とした。Al is used as a deoxidizing agent, but if it is less than 0.005%, its effect is not sufficient, and if it exceeds 0.080%, the cleanliness of steel may be impaired, so the addition range is 0.005 ≦ sol.Al ≦
It was set to 0.080%.
以上のような基本成分に対し本発明では必要に応じ以下
の成分の１種または２種以上を含有させる。In the present invention, in addition to the above basic components, one or more of the following components are contained as necessary.
0.05≦Ni≦0.80％。0.05 ≦ Ni ≦ 0.80%.
Niは、母材靭性、脆性亀裂伝播停止性能を向上させる目
的で添加する元素であるが、経済性及び有効性の点から
範囲を0.05≦Ni≦0.80％とした。Ni is an element added for the purpose of improving the base material toughness and brittle crack propagation arresting performance, but the range was set to 0.05 ≦ Ni ≦ 0.80% from the viewpoint of economic efficiency and effectiveness.
0.05≦Cr≦1.5％。0.05 ≦ Cr ≦ 1.5%.
Crは焼入れ性を向上させ、加速冷却における強度向上効
果を一層増大させる元素であるが、経済性と有効性を考
慮しその範囲を0.05≦Cr≦1.5％とした。Cr is an element that improves hardenability and further enhances the strength improving effect in accelerated cooling, but its range was set to 0.05 ≤ Cr ≤ 1.5% in consideration of economic efficiency and effectiveness.
0.03≦Mo≦0.50％。0.03 ≦ Mo ≦ 0.50%.
Moは、前記Crと同様に焼入れ性を向上させ、加速冷却に
よる強化作用に対し有効に作用する元素であって、経済
性及び有効性の点から範囲を0.03≦Mo≦0.50％とした。Mo is an element that improves the hardenability similarly to Cr and effectively acts on the strengthening effect by accelerated cooling, and the range is 0.03 ≦ Mo ≦ 0.50% from the viewpoint of economical efficiency and effectiveness.
0.01≦Ｖ≦0.20％。0.01 ≦ V ≦ 0.20%.
Ｖは微量添加で析出強化に有効に作用する元素であり、
強度向上に有効に働くが、0.01％未満では効果が少な
く、0.20％超えると靭性面で有害となることがあるので
添加範囲を0.01≦Ｖ≦0.20％とした。V is an element that effectively acts on precipitation strengthening when added in a trace amount,
Although it works effectively for improving the strength, if it is less than 0.01%, the effect is small, and if it exceeds 0.20%, it may be harmful in terms of toughness, so the range of addition was made 0.01 ≦ V ≦ 0.20%.
0.03≦Ti≦0.10％。0.03 ≦ Ti ≦ 0.10%.
適量のTi添加はTiCによる析出強化に有効に寄与する
が、0.03％未満ではその効果が少なく、また0.10％を超
えると効果がほぼ飽和するのでその範囲を0.03≦Ti≦0.
10％とした。Addition of an appropriate amount of Ti effectively contributes to precipitation strengthening by TiC, but if it is less than 0.03%, its effect is small, and if it exceeds 0.10%, the effect is almost saturated, so the range is 0.03 ≦ Ti ≦ 0.
It was set to 10%.
0.0003≦Ｂ≦0.0030％。0.0003 ≦ B ≦ 0.0030%.
Ｂは、極く微量の添加で鋼の焼入れ性を向上させ組織改
善を通じて強靭化に作用するが、0.0003％未満ではその
効果が期待されず、一方0.0030％を超えると効果が飽和
するので、添加範囲を0.0003≦Ｂ≦0.0030％とした。B has the effect of improving the hardenability of steel and improving the toughness by improving the structure with the addition of a very small amount, but if it is less than 0.0003%, its effect is not expected, while if it exceeds 0.0030%, the effect saturates. The range was 0.0003 ≦ B ≦ 0.0030%.
次に上記のような成分を含有する鋼を本発明においては
以下に示すプロセスで製造する。Next, in the present invention, a steel containing the above components is manufactured by the following process.
加熱温度:950℃以上1250℃以下。Heating temperature: 950 ℃ to 1250 ℃.
スラブ加熱温度が950℃未満ではNbが未固溶のまま残る
こと及び圧延加工上困難を伴う等の問題が生じる。一
方、1250℃を超えるスラグ加熱は加熱時のオーステナイ
ト粒径を著しく粗大にし、圧延・時効後の機械的性質を
劣化させる。従って加熱温度を950℃以上、1250℃以下
とした。If the slab heating temperature is lower than 950 ° C, problems such as Nb remaining as a non-solid solution and difficulty in rolling process occur. On the other hand, heating the slag above 1250 ° C causes the austenite grain size during heating to become extremely coarse, deteriorating the mechanical properties after rolling and aging. Therefore, the heating temperature was set to 950 ° C or higher and 1250 ° C or lower.
圧延条件:900℃以上1000℃以下の温度範囲で50％以上の
圧延を施し、800℃を超え900℃以下の温度範囲で最終仕
上りとなる圧延を実施する。Rolling conditions: Roll 50% or more in the temperature range of 900 ° C or more and 1000 ° C or less, and perform final rolling in the temperature range of 800 ° C or more and 900 ° C or less.
圧延条件は本発明の基本的な構成要件であり、その特徴
は２段階の圧延を規定しているところにある。The rolling condition is a basic constituent feature of the present invention, and its characteristic is that it regulates rolling in two stages.
第１段圧延:900℃以上1000℃以下の範囲で50％以上の圧
延を行う。First stage rolling: Rolling 50% or more in the range of 900 ° C to 1000 ° C.
この圧延の規定は再結晶域での圧延に関するものであ
る。再結晶域圧延によってオーステナイト粒を細粒化さ
せ機械的性質を向上させ得ることは一般的に良く知られ
ているが、本発明の特徴は従来の温度域より高温側に規
定していることである。即ち、900℃未満の温度域ではC
uの再結晶抑制効果のため未再結晶領域となり、再結晶
による細粒化効果が十分に期待できない。一方、1000℃
を超える温度域による圧下は、再結晶はするものの再結
晶後の粒径が十分細かくならない上、再結晶完了後粒成
長を起こすという問題もある。従って第１段階の温度域
を900℃以上1000℃以下に規定した。This rolling regulation relates to rolling in the recrystallization zone. It is generally well known that the austenite grains can be refined by the recrystallization zone rolling to improve the mechanical properties, but the feature of the present invention is that it is specified on the higher temperature side than the conventional temperature range. is there. That is, in the temperature range below 900 ° C, C
Due to the recrystallization suppressing effect of u, it becomes a non-recrystallized region, and the grain refining effect due to recrystallization cannot be expected sufficiently. On the other hand, 1000 ℃
The rolling down in the temperature range of more than 100 ° C causes recrystallization, but the grain size after recrystallization is not sufficiently fine, and there is also a problem that grain growth occurs after the completion of recrystallization. Therefore, the temperature range of the 1st stage was specified above 900 ℃ and below 1000 ℃.
また圧下量については、50％未満の圧下では十分な再結
晶が期待できないので上記圧延温度域で50％以上の圧延
を行う。As for the reduction amount, sufficient recrystallization cannot be expected if the reduction amount is less than 50%, so rolling is performed at 50% or more in the above rolling temperature range.
第２段圧延:800℃を超え900℃未満の温度範囲で最終仕
上りとなる圧延を実施する。Second-stage rolling: Rolling to achieve the final finish is performed in the temperature range of more than 800 ° C and less than 900 ° C.
この圧延の規定は未再結晶域での圧延に関するものであ
る。再結晶圧延後に未再結晶域圧延を施すことにより、
変態組織の一層の細粒化を図るものである。800℃以下
の圧延の実施は圧延能率の面で著しく不利となり、一方
900℃以上の温度域では未再結晶域の圧延とならない。
従って第２段階の温度域を800℃を超え900℃未満の範囲
に規定した。This rolling regulation relates to rolling in the non-recrystallized region. By performing the recrystallization rolling after the recrystallization rolling,
This is intended to further refine the transformation structure. Performing rolling at 800 ° C or lower is extremely disadvantageous in terms of rolling efficiency.
Rolling does not occur in the non-recrystallized region at temperatures above 900 ° C.
Therefore, the temperature range of the second stage was defined as the range over 800 ℃ and under 900 ℃.
冷却条件：圧延後直に２℃/S以上50℃/S以下の冷却速度
で550℃以下の温度範囲まで冷却する。Cooling conditions: Immediately after rolling, the material is cooled to a temperature range of 550 ° C or less at a cooling rate of 2 ° C / S or more and 50 ° C / S or less.
圧延後の冷却は、変態組織を細粒の低温変態組織主体と
して強度靭性を向上させることを目的としている。即
ち、２℃/S未満の冷却速度では十分な強靭化が達成でき
なく、また50℃/Sを超える冷却は過大な冷却設備が必要
となり経済的に不利となる。一方、550℃を超える温度
で冷却を停止すると、変態強化が不十分となり強靭化が
達成されない。従って、冷却速度範囲を２℃/S以上50℃
/S以下とし、冷却停止温度を550℃以下に規定する。The purpose of cooling after rolling is to improve the strength and toughness with the transformation structure mainly composed of a fine-grained low-temperature transformation structure. That is, sufficient toughness cannot be achieved at a cooling rate of less than 2 ° C / S, and cooling at more than 50 ° C / S requires an excessive cooling facility, which is economically disadvantageous. On the other hand, if cooling is stopped at a temperature higher than 550 ° C, transformation strengthening becomes insufficient and toughness cannot be achieved. Therefore, the cooling rate range is 2 ℃ / S or more and 50 ℃
/ S or less, and the cooling stop temperature is specified at 550 ° C or less.
更に時効処理は冷却後の組織に過飽和に固溶したCu、N
b、Ｖを、Cuについてはε−Cuとして、Nb、Ｖについて
は炭窒化物として析出せしめ、板厚にかかわらずその中
心部に到るまで良好な強度を確保させる。その具体的な
条件は500℃以上、650℃以下の温度で10〜60分均熱処理
するもので、この時効処理温度が500℃未満では析出が
得られず、また600℃を超える温度では過時効となり、
適正な温度条件の場合に比較して強度が相当に低下す
る。Furthermore, the aging treatment is Cu, N which is a supersaturated solid solution in the structure after cooling.
b and V are deposited as ε-Cu for Cu and carbonitrides for Nb and V to ensure good strength up to the central portion regardless of the plate thickness. The specific conditions are soaking at a temperature of 500 ° C or higher and 650 ° C or lower for 10 to 60 minutes. Precipitation is not obtained when the aging temperature is lower than 500 ° C, and overaging is performed at a temperature higher than 600 ° C. Next to
The strength is considerably reduced as compared with the case of appropriate temperature conditions.
本発明によるものの具体的な製造例について説明すると
以下の如くである。A concrete production example of the device according to the present invention is as follows.
本発明者等が用いた本発明に従った鋼およびその比較鋼
についての成分組織は次の表１に示す通りである。The compositional structures of the steel according to the present invention and the comparative steel used by the present inventors are as shown in Table 1 below.
即ち本発明における鋼成分組成上、特徴をなす0.6≦Cu
≦1.5％の範囲内のCuが添加されている成分例がＣ〜Ｆ
鋼、Ｈ〜Ｏ鋼であって、A,B,G鋼はCuが本発明範囲外の
成分例である。また、Ａ〜Ｇ鋼は、Ni,Cr,Mo等の合金元
素を含まないＣ−Mn−Cu−Nb系であり、これに対しＨ、
Ｉ、Ｊ鋼はそれぞれNi,Cr,Moを単独添加をしたものであ
って、Ｋ鋼、Ｎ鋼はNi,Cr,Moを同時に添加した例であ
り、更にＬ、Ｍ、Ｏ鋼は微量元素であるＶ、Ti、Ｂが添
加されている。 That is, in terms of the steel composition in the present invention, the characteristic 0.6 ≦ Cu
Examples of components with Cu added within the range of ≦ 1.5% are C to F
Among the steels, H to O steels, A, B and G steels have Cu as an example of a component outside the scope of the present invention. Further, the A to G steels are C-Mn-Cu-Nb series which do not contain alloy elements such as Ni, Cr and Mo, whereas H,
The I and J steels are the ones in which Ni, Cr, and Mo are added individually, the K steel and the N steel are the examples in which Ni, Cr, and Mo are simultaneously added, and the L, M, and O steels are trace elements. V, Ti, and B are added.
また、実施した製造条件及び得られた機械的性質は第２
表に示す如くであって、時効処理は500〜600℃×10〜60
分である。ここで、製造例１〜６は本発明範囲内の同一
製造条件のもので、Cu量の異なるＡ〜ＣおよびＥ〜Ｇ鋼
を製造した場合の特性例であり、本発明成分組成条件を
満足するＣ〜Ｆ鋼はいずれもYS≧60kgf/mm2、TS≧65kgf
/mm2、vTrs≦−120℃の何れも満足するという優れた強
度・靭性を示すことがわかる。これに対し、Cu＜0.6％
のＡ、Ｂ鋼、Cu＞1.5％のＧ鋼は強度あるいは靭性が劣
る。また製造例７〜13は本発明に従う成分の鋼であるＤ
鋼を用い製造条件を変えて製造した特性例である。製造
例７、10、11はＤ鋼を用い本発明範囲内で製造したもの
であり、優れた強靭性が付与されていることがわかる。
これに対し、製造例８、９、12、13はそれぞれ再結晶域
圧延の温度域、圧下率、圧延後の冷却速度、停止温度が
本発明範囲外のものであり、いずれもv Trs≧−70℃で
あり十分な靭性が得られていない。一方、製造例14〜20
は本発明鋼であるＨ鋼〜Ｏ鋼に対し本発明範囲内で製造
したものであり、いずれも優れた強度、靭性が付与され
ていることがわかる。Also, the manufacturing conditions used and the mechanical properties obtained are
As shown in the table, the aging treatment is 500 ~ 600 ℃ × 10 ~ 60
Minutes. Here, Production Examples 1 to 6 are the same production conditions within the scope of the present invention, and are characteristic examples when A to C and E to G steels having different Cu contents are produced, and satisfy the component composition conditions of the present invention. For all C to F steels, YS ≧ 60kgf / mm 2 , TS ≧ 65kgf
It can be seen that it exhibits excellent strength and toughness that satisfy both of / mm 2 and vTrs ≦ −120 ° C. On the other hand, Cu <0.6%
The A and B steels and the G steel with Cu> 1.5% are inferior in strength or toughness. Further, Production Examples 7 to 13 are steels having the composition according to the present invention D
It is a characteristic example manufactured by changing manufacturing conditions using steel. Manufacturing Examples 7, 10 and 11 are manufactured within the scope of the present invention using D steel, and it is understood that excellent toughness is imparted.
On the other hand, in Production Examples 8, 9, 12, and 13, the temperature range of the recrystallization zone, the rolling reduction, the cooling rate after rolling, and the stop temperature were outside the scope of the present invention, respectively, and v Trs ≧ − It is 70 ° C and sufficient toughness is not obtained. On the other hand, Production Examples 14 to 20
Are produced within the scope of the present invention with respect to the steels of the present invention, H steel to O steel, and it is understood that all of them have excellent strength and toughness.
なお前記したＤ鋼に関し加熱温度1050℃、圧延後に加熱
冷却したものについて、圧延仕上り温度を変えた場合の
強度、靭性および圧延時間の変化を要約して示している
のが添附図面であって900℃を超える圧延条件は強度、
能率の面で有利であるとしても靭性的には著しく劣るこ
とが明らかである。これに対し800℃未満の場合におい
ては圧延能率面において急激に不利となるもので、本発
明における圧延仕上り温度を採用することによってこれ
らの関係を略適切に満足し好ましい生産性確保した鋼板
の製造が可能となる。又本発明者等は前記した表１中の
本発明鋼に対し、低温割れ感受性を検討すべく斜めｙ型
溶接割れ試験を行ったところ、何れも予熱を施さない25
℃の条件であっても割れは全く生じなかった。また入熱
40KJ/cmの条件で溶接した溶接熱影響部のシャルピー、C
TOD特性も低温で充分なものであることが確認された。 With respect to the D steel described above, the attached drawing is a summary of changes in strength, toughness, and rolling time when the rolling finishing temperature is changed in the case where the heating temperature is 1050 ° C. and the material is heated and cooled after rolling. The rolling conditions above ℃ are strength,
It is clear that even if it is advantageous in terms of efficiency, it is significantly inferior in toughness. On the other hand, in the case of less than 800 ℃, there is a sudden disadvantage in terms of rolling efficiency, and by adopting the rolling finish temperature in the present invention, production of a steel sheet that satisfies these relationships substantially appropriately and secures favorable productivity. Is possible. Further, the inventors of the present invention conducted an oblique y-type weld cracking test on the steels of the present invention shown in Table 1 above in order to examine the low temperature cracking susceptibility.
No cracking occurred at all even under the condition of ° C. Heat input again
Charpy of welded heat-affected zone welded under the condition of 40 KJ / cm, C
It was confirmed that the TOD characteristics were also sufficient at low temperatures.
「発明の効果」 以上説明したような本発明によるときは、制御圧延条件
を緩和することができて圧延能率を向上し、又圧延機の
負荷を軽減し、PCMの低い成分系の鋼種で強度確保が可
能であって低温割れ感受性や熱影響部の靭性のような溶
接施工性の改善され、YS、TSおよびvTrsの何れにおいて
も優れた高強度、高靭性鋼板を簡易且つ低コストに得し
めるものであって、工業的にその効果の大きい発明であ
る。When according to the invention as described "Effect of the Invention" above, it is possible to relax the control rolling conditions to improve rolling efficiency and also to reduce the load of the mill, in steels with low component of P CM It is possible to secure strength, improve welding workability such as cold cracking susceptibility and toughness of heat affected zone, and easily obtain high strength and high toughness steel plate excellent in YS, TS and vTrs at low cost. It is an invention that has a large effect industrially.
図面は本発明の技術的内容を示すものであって、圧延仕
上り温度を変えた場合の強度、靭性、圧延時間の変化を
示した図表である。The drawings show the technical contents of the present invention, and are charts showing changes in strength, toughness, and rolling time when the rolling finishing temperature is changed.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大森 俊道 東京都千代田区丸の内１丁目１番２号 日 本鋼管株式会社内 (56)参考文献 特開 昭60−59018（ＪＰ，Ａ) 特開 昭58−96817（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshimichi Omori 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (56) Reference JP-A-60-59018 (JP, A) JP-A Sho 58-96817 (JP, A)
Claims (2)
950〜1250℃に加熱してから900〜1000℃の温度範囲で50
％以上の圧延を施し、800℃を越え900℃未満で最終仕上
げ圧延をなし、その後直ちに２〜50℃/secの冷却速度で
550℃以下の温度域まで冷却し、次いで時効処理を行う
ことを特徴とする高張力高靭性鋼板の製造方法。1. C: 0.01 to 0.10 wt%, Si: 0.01 to 0.80 wt%, Mn: 0.20 to 2.0 wt%, Cu: 0.6 to 1.5 wt%, Nb: 0.005 to 0.060 wt%, sol.Al: 0.005 ~ 0.080wt% with the balance Fe and unavoidable impurities
50 to 900-1000 ℃ temperature range after heating to 950-1250 ℃
% Or more, and finally finish rolling at over 800 ℃ and under 900 ℃, then immediately at a cooling rate of 2-50 ℃ / sec.
A method for producing a high-strength, high-toughness steel sheet, which comprises cooling to a temperature range of 550 ° C or lower and then performing an aging treatment.
不可避的不純物からなる鋼を950〜1250℃に加熱してか
ら900〜1000℃の温度範囲で50％以上の圧延を施し、800
℃を越え900℃未満で最終仕上げ圧延をなし、その後直
ちに２〜50℃/secの冷却速度で550℃以下の温度域まで
冷却し、次いで時効処理を行うことを特徴とする高張力
高靭性鋼板の製造方法。2. C: 0.01 to 0.10 wt%, Si: 0.01 to 0.80 wt%, Mn: 0.20 to 2.0 wt%, Cu: 0.6 to 1.5 wt%, Nb: 0.005 to 0.060 wt%, sol.Al: 0.005 ~ 0.080wt%, Ni: 0.05-0.8wt%, Cr: 0.05-1.5wt%, Mo: 0.03-0.5wt%, V: 0.01-0.20wt%, Ti: 0.03-0.10wt%, B 50% or more in the temperature range of 900 to 1000 ° C after the steel containing 0.0003 to 0.003wt% of any one kind or two or more kinds and the balance consisting of Fe and unavoidable impurities is heated to 950 to 1250 ° C Rolled to 800
High-tensile high-toughness steel sheet characterized by performing final finishing rolling at a temperature above 900 ° C and below 900 ° C, immediately thereafter cooling to a temperature range of 550 ° C or less at a cooling rate of 2 to 50 ° C / sec, and then performing an aging treatment. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61097849A JPH0781164B2 (en) | 1986-04-30 | 1986-04-30 | Method for manufacturing high-strength and high-toughness steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61097849A JPH0781164B2 (en) | 1986-04-30 | 1986-04-30 | Method for manufacturing high-strength and high-toughness steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62256915A JPS62256915A (en) | 1987-11-09 |
| JPH0781164B2 true JPH0781164B2 (en) | 1995-08-30 |
Family
ID=14203181
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61097849A Expired - Fee Related JPH0781164B2 (en) | 1986-04-30 | 1986-04-30 | Method for manufacturing high-strength and high-toughness steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0781164B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015022729A1 (en) | 2013-08-13 | 2015-02-19 | 新日鐵住金株式会社 | Steel plate |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0735538B2 (en) * | 1988-07-04 | 1995-04-19 | 株式会社神戸製鋼所 | Method for manufacturing high strength and high toughness thick steel plate with excellent weldability |
| JPH0826395B2 (en) * | 1988-11-08 | 1996-03-13 | 新日本製鐵株式会社 | 80 kgf / mm with excellent weldability (2) High-strength steel manufacturing method |
| JPH0794687B2 (en) * | 1989-03-29 | 1995-10-11 | 新日本製鐵株式会社 | Method for producing HT80 steel excellent in high weldability, stress corrosion cracking resistance and low temperature toughness |
| JPH07116504B2 (en) * | 1990-12-25 | 1995-12-13 | 株式会社神戸製鋼所 | Manufacturing method of 50 kg class low yield ratio thick high-strength steel plate having a plate thickness of 50 mm or more with a small hardness difference in the plate thickness direction |
| JP3087550B2 (en) * | 1993-11-25 | 2000-09-11 | キヤノン株式会社 | Small zoom lens |
| KR100415657B1 (en) * | 1996-12-18 | 2004-03-31 | 주식회사 포스코 | METHOD FOR MANUFACTURING ULTRA-HIGH TENSILE STRENGTH STEEL HAVING 220 ksi CLASS YIELD STRENGTH |
| KR100325705B1 (en) * | 1997-12-27 | 2002-06-26 | 이구택 | High strength lecture manufacturing method |
| US6558483B2 (en) | 2000-06-12 | 2003-05-06 | Sumitomo Metal Industries, Ltd. | Cu precipitation strengthened steel |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5896817A (en) * | 1981-12-07 | 1983-06-09 | Sumitomo Metal Ind Ltd | Production of high tensile hot rolled steel material having high toughness |
| JPS6059018A (en) * | 1983-08-03 | 1985-04-05 | Nippon Steel Corp | Production of cu-added steel having excellent weldability and low-temperature toughness |
-
1986
- 1986-04-30 JP JP61097849A patent/JPH0781164B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015022729A1 (en) | 2013-08-13 | 2015-02-19 | 新日鐵住金株式会社 | Steel plate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62256915A (en) | 1987-11-09 |
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