JPS58210125A - Production of strong and tough high tensile steel plate by direct hardening method - Google Patents
Production of strong and tough high tensile steel plate by direct hardening methodInfo
- Publication number
- JPS58210125A JPS58210125A JP9372782A JP9372782A JPS58210125A JP S58210125 A JPS58210125 A JP S58210125A JP 9372782 A JP9372782 A JP 9372782A JP 9372782 A JP9372782 A JP 9372782A JP S58210125 A JPS58210125 A JP S58210125A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- rolling
- toughness
- temperature
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、直接焼入法によって靭性の高い高張力鋼板
を製造する方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high tensile strength steel plate with high toughness by a direct quenching method.
近年、エネルギー需要の増大とともにアラスカ等の極寒
地域、あるいは海底等、苛酷な環境におけるガス田や油
田が数多く開発されており、これらから供給される天然
ガスや原油はほとんどラインパイプによって必要とされ
る場所まで輸送されるようになってきている。In recent years, as energy demand has increased, many gas and oil fields have been developed in harsh environments such as in extremely cold regions such as Alaska or on the ocean floor, and most of the natural gas and crude oil supplied from these fields is required through line pipes. Increasingly, it is being transported to different locations.
このため、ラインパイプの需要も急増してきている上に
、大径でかつ耐圧性に優れたものを採用して輸送効率の
向上を図る傾向が強まってきているため、これに応える
べく、より厚肉で、強度。For this reason, the demand for line pipes is rapidly increasing, and there is a growing trend to improve transportation efficiency by adopting larger diameter pipes with excellent pressure resistance. Meat and strength.
靭性、並びに溶接性により優れたラインパイプ材の開発
が急務となっているのが現状である。Currently, there is an urgent need to develop line pipe materials with superior toughness and weldability.
すなわち、海底ラインパイプや寒冷地ラインパイプでは
、厚肉高強度化の必要が叫ばれており、また厳しい建設
環境のために溶接性に優れていることが必須の要件とさ
れているのである。In other words, submarine line pipes and cold region line pipes are required to have thick walls and high strength, and excellent weldability is also an essential requirement due to the harsh construction environment.
ところが、従来、ラインパイプ用に供せられていた圧延
のままの鋼板では、その成分組成等を如何に工夫しても
上記要望を満たすようなものを得ることができず、最近
では、圧延の条件、冷却の条件、および鋼材成分組成の
３者に工夫を凝らして組合せることが前記問題を解決で
きる近道であるとの認識に立って、直接焼入法や加速冷
却法等の、圧延直後の鋼板を水冷して高強度化を図る方
法が実施されるようになってきた。However, no matter how much we try to improve the composition of as-rolled steel sheets that have traditionally been used for line pipes, it has not been possible to obtain a product that satisfies the above requirements. Recognizing that the shortcut to solving the above problem is to combine the three factors of conditions, cooling conditions, and steel material composition, we have developed methods such as direct quenching and accelerated cooling that are effective immediately after rolling. A method of water-cooling steel plates to increase their strength has begun to be implemented.
直接焼入法とは、マルテンサイトやベイナイトの焼入組
織の有する高強度を活用するものであって、一般的には
鋼のオーステナイト域（通常は７５０℃以上である）で
圧延を終了し、次いでこれをＡｒ３点以上から直接に焼
入れすることを特徴とする高張力鋼板の製造法であるカ
ー、この方法によれば高強度の鋼材を得ることはできる
けれども、低温靭性に難点が残るものである。The direct quenching method utilizes the high strength of the quenched structures of martensite and bainite, and generally finishes rolling in the austenite region of the steel (usually at 750°C or higher). This is then directly quenched at Ar 3 points or above, which is a method for manufacturing high-strength steel sheets.Although this method makes it possible to obtain high-strength steel materials, it still suffers from low-temperature toughness. be.
また、加速冷却法は、制御ＩＦ ／４ ＋ｉ−の鋼板の
オーステナイトからフェライトへの変態域、即ちＡｒ３
〜Ａｒ、を空冷よりも速い冷却速度で冷却し、一部微細
ペイナイトの高強度を活用することもあるが、６００〜
５５０℃で前記加速冷却をストップすることを特徴とす
る高張力鋼板の製造法であり、細粒フェライトまたは一
部に微細ベイナイトを組合せて高強度化を図ったもので
ある。そして、この方法によれば、引張り強さ： ６０
ｋｇ７）ｇ１級鋼、またはｘ−７０級（ＡＰＩ規格）
のラインパイプ程度までの製造に適する鋼材を得ること
ができるが、厳しい加速冷却条件の制約、すなわち、冷
却開始温度、冷却速度、冷却終了温度等を厳しく調整す
る必要があるために、鋼材製造の作業性が悪くなるとい
う問題を有するものであった。In addition, the accelerated cooling method is applied to the transformation region from austenite to ferrite of the steel plate at control IF /4 +i-, that is, Ar3
~Ar is cooled at a faster cooling rate than air cooling, and the high strength of fine paynite is sometimes utilized, but 600 ~
This is a method for manufacturing a high-strength steel sheet characterized by stopping the accelerated cooling at 550° C., and is intended to increase the strength by combining fine-grained ferrite or part of fine bainite. According to this method, tensile strength: 60
kg7) G1 class steel or x-70 class (API standard)
It is possible to obtain steel materials that are suitable for manufacturing up to line pipes, but strict restrictions on accelerated cooling conditions, such as the need to strictly adjust cooling start temperature, cooling rate, cooling end temperature, etc., make it difficult to manufacture steel materials. This had the problem of poor workability.
他方、最近に至って、制御圧延鋼にＴｉおよびＢを添加
して良好な靭性を有するベイナイト高張力鋼板を製造し
ようとの技術も提案されているが、このようなベイナイ
ト高張力鋼板を製造するにあたって、従来法どおりの直
接焼入れ、または加速冷却を施してその靭性値を高めよ
うとしても、所望とする靭性を得ることができないばか
りが、逆に靭性が大幅に劣化するということがわかった
。On the other hand, recently, a technology has been proposed to add Ti and B to controlled rolled steel to produce bainitic high-strength steel sheets with good toughness. It was found that even if an attempt was made to increase the toughness value by applying direct quenching or accelerated cooling as in conventional methods, the desired toughness could not be obtained, and on the contrary, the toughness deteriorated significantly.
しかも、制御圧延によるＢ処理鋼の圧延後水冷による強
靭化は、従来知られている技術をもってしても如何とも
し難いものであるとの結果が今日の研究で明らかになっ
た。Moreover, today's research has revealed that it is difficult to strengthen B-treated steel by controlled rolling by water cooling after rolling, even with conventionally known techniques.
本発明者等は、上述のような観点から、製造作業性が良
好で、そして溶接性に好適である低い炭素当量が確保で
き、かつ強度がＸ−７０−Ｘ−１００級（引張強さ：６
０〜８０ゆ／−１降伏強度二４９〜７ ｏ １ｇ７’ｔ
ｄ ） 、靭性がシャルピー破面遷移温度（ｖＴｓ）で
−１００℃以下程度を示すような強靭高張力鋼板を製造
すべく、種々研究を重ねた結果、以下（ａ）〜（ｄ）に
示す如き知見を得るに至ったのである。すなわち、
（ａ） 高強度を得るためにＮｂ、 Ｔｉ 、および
Ｂを添加して微細マルテンサイトの生成促進を図った鋼
のＣ量を所定値以下に抑えることにより細粒フェライト
が生成し、これによって鋼の靭性が著しく改良される上
に、溶接性も向」−すること、（ｂ） 上記（ａ）項
に示した鋼を低温加熱後、低温域にて大圧下すると、歪
をもった微細なオーステナイトが形成される。そして、
−これから微細なフェライト生成されるのであるが、こ
の低温域での大圧下が微細フェライトの生成を一層促進
するものであること、
（Ｃ） 鋼板製造の際、上述のように低温域にて高Ｉ
Ｆ下率の圧延を施し、微細フェライトをまず十分に生成
させた後、固溶Ｎｂおよび固溶Ｂの共存によって未変態
のまま存在する微細なオーステナイトを６００〜３５０
℃（Ｍｓ点より上）から焼入れすると、残留オーステナ
イトから微細な分散したマルチンサイトを生じ、結局、
フェライト＋マルテンサイトの二相混合組織鋼が得られ
、細粒フェライトの有する高靭性に加えて、微細マルテ
ンサイトの有する高強度をも備えた強靭高張力鋼板を確
実に得ることができること。すなわち、細粒加ニオース
テナイトの粒界から非情に細かいフェライトが析出し、
その中に残留する残留オーステナイトは焼入れによって
極く微細なマルテンサイトになり、組織的には極めて微
細なフェライトとマルテンサイトの混合組織となり、特
にＸ−７０−Ｘ−１００級の高強度が得られるとともに
、焼戻し工程が無くても高靭性が得られる。この場合、
従来の直接焼入法では、圧延後直ちに焼入処理するため
に、鋼板の冷却速度が速くなりすぎ、微細なポリゴナル
フエライトの生成を阻止して、ベイナイトまたはマルテ
ンサイト−相鋼となり、高強度ヲ示スものの、細粒フェ
ライトの優れた靭性効果を活用できないのである。即ち
、本発明では、圧延終了後、空冷または４℃／ｓｅｃ程
度の加速冷却の範囲の冷却により、まず鋼板中への微細
フェライトの析出処理を行なって靭性向上の下地を作っ
た後に％６００〜３５０℃の温度範囲から直接焼入れす
ることにより、未変態オーステナイト部をマルテンサイ
ト化すると高強度が達成できること。From the above-mentioned viewpoints, the present inventors were able to ensure good manufacturing workability, a low carbon equivalent that is suitable for weldability, and a strength of class X-70 to X-100 (tensile strength: 6
0~80 Yu/-1 Yield strength 249~7 o 1g7't
d) As a result of various studies in order to produce a tough, high-strength steel plate that exhibits toughness of approximately -100°C or less at the Charpy fracture transition temperature (vTs), we have developed the following (a) to (d). This led to the discovery of new knowledge. That is, (a) Fine grain ferrite is generated by suppressing the C amount below a predetermined value in steel in which Nb, Ti, and B are added to promote the formation of fine martensite in order to obtain high strength. (b) When the steel shown in item (a) above is heated at a low temperature and then reduced to a large extent in a low temperature range, it becomes distorted. Fine austenite is formed. and,
- Fine ferrite will be generated from this, and the large reduction in this low temperature range will further promote the formation of fine ferrite. (C) When manufacturing steel sheets, as mentioned above, I
After rolling at a lower rate of F to sufficiently generate fine ferrite, the fine austenite existing untransformed due to the coexistence of solid solution Nb and solid solution B is reduced to 600 to 350.
When quenched from ℃ (above the Ms point), fine dispersed martinsite is produced from the retained austenite, and eventually
It is possible to obtain a steel with a two-phase mixed structure of ferrite and martensite, and to reliably obtain a strong, high-strength steel plate having not only the high toughness of fine-grained ferrite but also the high strength of fine martensite. In other words, extremely fine ferrite precipitates from the grain boundaries of fine-grained niostenite,
The residual austenite that remains in it becomes extremely fine martensite by quenching, and the structure becomes a mixed structure of extremely fine ferrite and martensite, resulting in particularly high strength of X-70-X-100 class. In addition, high toughness can be obtained even without a tempering process. in this case,
In the conventional direct quenching method, the steel plate is quenched immediately after rolling, so the cooling rate of the steel plate is too fast, preventing the formation of fine polygonal ferrite and turning it into bainite or martensite phase steel, resulting in high strength. However, the excellent toughness effect of fine-grained ferrite cannot be utilized. That is, in the present invention, after rolling is completed, fine ferrite is first precipitated into the steel sheet by cooling in the range of air cooling or accelerated cooling at about 4° C./sec to prepare a base for improving toughness. High strength can be achieved by converting untransformed austenite into martensite by direct quenching from a temperature range of 350°C.
そして、これをさらに焼戻しするとより靭性が向上され
ること。そのうえ、フェライトも微細で強度が高いこと
に加えて、マルテンサイトはベイナイトよりもさらに高
強度を付与するので、低Ｃ化、低Ｃｅｑ （炭素当量）
化も容易であり、しかも極低Ｃ化を図れば衝撃値も向上
するのに加えて、溶接性もさらに改善されること、
（ｄ） 上記鋼に、さらにＣｕ、 Ｃｒ、 Ｍｏ 、
Ｎｉ、 Ｃｏ 、 Ｖ 。If this is further tempered, the toughness will be further improved. Furthermore, in addition to the fact that ferrite is fine and has high strength, martensite provides even higher strength than bainite, resulting in lower C and lower Ceq (carbon equivalent).
(d) In addition to the above-mentioned steel, Cu, Cr, Mo,
Ni, Co, V.
Ｚｒ、 Ｌａ、 Ｃｅ 、およびＣａの１種または２種
以上の所定量を添加することによって、鋼板の強度、お
よび靭性をよシ向上することができること。The strength and toughness of a steel plate can be improved by adding a predetermined amount of one or more of Zr, La, Ce, and Ca.
したがって、この発明は上記知見に基いてなされたもの
で、
Ｃ：０．００３〜０．１００％、Ｓｉ：０．８５％以下
、 Ｍｎ： １．０〜３．Ｏｓ、 Ｐ ： ０．０３
％以下、 Ｓ ：０．００９チ以下、Ｎｂ：０１００
８〜０１８０％、 Ｔｉ：０．００４〜００４０％、１
３ ：Ｏ，０Ｏ０４〜０．００２５ ｓ、 Ｎ ：Ｏ
，０Ｏ０５〜０．０１００％、５ｏｔ−Ａｌ ：０．０
０５〜０．０９０％。Therefore, this invention was made based on the above findings, and includes: C: 0.003 to 0.100%, Si: 0.85% or less, Mn: 1.0 to 3. Os, P: 0.03
% or less, S: 0.009 or less, Nb: 0100
8~0180%, Ti:0.004~0040%, 1
3:O,0O04~0.0025s, N:O
,0O05~0.0100%, 5ot-Al: 0.0
05-0.090%.
を含有するとともに、必要に応じて、さらに、Ｃｕ、Ｃ
ｒ、およびＭＯの１種以上：０．０５〜０．５０チ、
Ｎｉ、 ｋよびＣＯの１種以上：０．ｌ〜ｌ Ｏ％
。and, if necessary, further contain Cu, C
r, and one or more kinds of MO: 0.05 to 0.50, one or more kinds of Ni, k, and CO: 0. l～l O%
.
■、およびＺｒの１種以上： ０．０１〜’０．１５
％、Ｌａ、Ｃｅ、およびＣａの１種以上：Ｏ，０Ｏ０５
〜０００２０チ、
を単独または複合して含有し、
Ｆｅおよび不可避不純物：残シ、
（以上重量％、なお、以下、組成成分の含有割合を表わ
すチは重量％とする）からなる鋼を、９００〜１１７０
℃に加熱した後、少なくとも９００℃以下の累積圧下率
が５０チ以上で、かつ仕上温度が８００〜６５０℃の圧
延を施し、圧延仕上後、空冷または４℃／秒を越えない
加速冷却により６００〜３５０℃の範囲に冷却してから
、この温度範囲より直接焼入れすることにより、優れた
靭性と高い強度を有する高張力鋼板を得るごとに特徴を
有するものである。■, and one or more types of Zr: 0.01 to '0.15
%, one or more of La, Ce, and Ca: O, 0O05
~00020% of steel, containing either alone or in combination, Fe and unavoidable impurities: (the above weight %, hereinafter, the content ratio of the composition component is referred to as weight%) is made of 900% ~1170
After heating to a temperature of at least 900°C, rolling is carried out at a cumulative reduction rate of at least 50 inches and a finishing temperature of 800 to 650°C, and after finishing the rolling, air cooling or accelerated cooling not exceeding 4°C/second is carried out to a temperature of 600°C. By cooling to a range of ~350°C and then directly quenching from this temperature range, a high tensile strength steel plate with excellent toughness and high strength is obtained.
すなわち、前述のように、従来公知の直接焼入法は、Ａ
ｒ３点以上で圧延を終了し、Ａｒ３点以上から焼入れす
るものであり、同じ〈従来公知の加速冷却法は、Ａｒ３
〜Ａｒ１点を急冷した後放冷するものであるのに対して
、この発明は、特定成分組成の低Ｃ−Ｎｂ−Ｔｉ−Ｂ鋼
を圧延し、Ａｒ、点以下（６００℃以下）から焼入れす
ることによってベイナイト変態を阻止し、細粒フェライ
トと微細マルテンサイトの二相混合組織鋼板を得るよう
にしたものである。That is, as mentioned above, the conventionally known direct quenching method
Rolling is finished at the r3 point or higher, and hardening is started at the Ar3 point or higher.
In contrast to the method in which a low C-Nb-Ti-B steel with a specific composition is rapidly cooled at 1 point to Ar and then allowed to cool, the present invention involves rolling a low C-Nb-Ti-B steel with a specific composition and quenching it from below the Ar point (600°C or less). By doing so, bainite transformation is prevented and a steel sheet with a two-phase mixed structure of fine ferrite and fine martensite is obtained.
つぎに、この発明の強靭高張力鋼板の製造法において、
化学組成成分量、圧延条件、冷却条件、および焼入温度
を上述のように限定した理由を説明する。Next, in the method for manufacturing a strong and high tensile strength steel plate of this invention,
The reason why the amount of chemical composition components, rolling conditions, cooling conditions, and quenching temperature are limited as described above will be explained.
■）化学組成成分量
■ Ｃ
Ｃ成分には、鋼材の強度を確保する作用があるが、その
含有量が０．００３％未満では前記作用に所望の効果が
得られず、他方０．１００％を越えて含有せしめると微
細フェライトの生成が減少してマルテンサイトの量が増
し所望の靭性を得ることができなくなる上、溶接性をも
劣化するようになることから、その含有量を０．０３〜
Ｑ、、１００％と限定した。■) Chemical composition component amount ■ C The C component has the effect of ensuring the strength of steel materials, but if its content is less than 0.003%, the desired effect cannot be obtained, and on the other hand, 0.100% If the content exceeds 0.03, the formation of fine ferrite will decrease and the amount of martensite will increase, making it impossible to obtain the desired toughness and also deteriorating weldability. ~
Q. It was limited to 100%.
■ ５Ｉ
Ｓ１成分は、脱酸の故に鋼に必然的に含有される元素で
あるが、その含有量が０．８５％を越えると鋼の靭性及
び溶接性に悪影響を及ぼすようになることから、その含
有量を０．８５％以下に制限した。■ 5I S1 component is an element that is inevitably contained in steel for deoxidation, but if its content exceeds 0.85%, it will have a negative effect on the toughness and weldability of steel. Its content was limited to 0.85% or less.
−■ Ｍｎ
Ｍｎ成分には、焼入性を向上して鋼の強度および靭性を
改善する作用があるが、その含有量が１０係未満ではマ
ルテンサイトの生成が困難となって前記作用に所望の効
果が得られず、他方３．０％を越えて含有させると逆に
靭性が低下するとともに溶接性にも悪影響を与え、細粒
フェライト生成も困難となることから、その含有量を１
０〜３３．○チと限定した。-■ Mn The Mn component has the effect of improving hardenability and improving the strength and toughness of steel, but if its content is less than 10 parts, it becomes difficult to generate martensite and the desired effect cannot be achieved. On the other hand, if the content exceeds 3.0%, the toughness will decrease, it will have a negative effect on weldability, and it will be difficult to generate fine-grained ferrite, so the content should be reduced to 1.
0-33. I limited it to ○chi.
■ Ｐ
Ｓ成分は、通常は不可避不純物として含有される程度の
ものであり、好ましい成分ではないが、特にその含有量
が０．０３ ％を越えた場合には溶接性の低下や偏析に
よる鋼の内質劣化の弊害が出てくるようになることから
、その含有量を００３％以下と制限した。■ PS component is normally contained as an unavoidable impurity and is not a desirable component, but especially if its content exceeds 0.03%, it may deteriorate weldability or cause segregation in the steel. The content was limited to 0.003% or less because the negative effects of internal quality deterioration would appear.
■ Ｓ
Ｓ成分も、通常は不可避不純物として鋼に必然的に含有
されるものであるが、その含有量が０．００９チを越え
るとシャルピーの横方向エネルギー吸収に著しい悪影響
を与えるようになることがら、その誉有量をＯ，ＯＯ９
％以下と限定した。■ S The S component is also normally contained in steel as an unavoidable impurity, but if its content exceeds 0.009 inch, it will have a significant negative effect on Charpy's lateral energy absorption. However, the amount of honor is O, OO9
% or less.
■ Ｎｂ
Ｎｂ成分には、細粒フェライトの生成を促し、Ｉ〕との
共存においてマルテンサイト形成をも促進して、強度お
よび靭性を向上する作用があるが、その含有量がＯ，Ｏ
Ｏ８％未満では前記作用に所望の効果を得ることができ
ず、他方０１８０％を越えて含有せしめると溶接性に悪
影響を与えるようになることから、その含有量を０．０
０８〜０１８０％と限定した。■ Nb The Nb component promotes the formation of fine-grained ferrite and also promotes the formation of martensite in coexistence with [I], thereby improving strength and toughness.
If the O content is less than 8%, the desired effect cannot be obtained, and if the O content exceeds 180%, it will have a negative effect on weldability. Therefore, the content should be reduced to 0.0%.
It was limited to 08-0180%.
■ Ｔｌ
Ｔｉ成分には、圧延組織を微細化するとともに、鋼中の
Ｎを固定してＳ成分の焼入性向上効果を確保する作用が
あるが、その含有量が０．００４％未満では前記作用に
所望の効果を得ることができず、他方０．０４０％を越
えて含有せしめると靭性の劣化を来たすようになること
から、その含有量をＯ，ＯＯ−４〜０゜０４０チと限定
した。■ The Tl Ti component has the effect of refining the rolled structure and fixing N in the steel to ensure the hardenability improvement effect of the S component, but if its content is less than 0.004%, the above-mentioned The desired effect cannot be obtained, and if the content exceeds 0.040%, the toughness deteriorates, so the content is limited to O,OO-4 to 0°040%. did.
■ Ｂ
Ｓ成分には、鋼の焼入性を向上させて強度および靭性を
確保する作用があるが、その含有量が０、 ＯＯ（’１
４ ％未満では焼入性が不十分で満足出来る強靭性を得
ることができず、他方０．００２５％を越えて含有せし
めると溶接性に悪影響を及ぼすように々ることがら、そ
の含有量を０．０００４〜０．００２５係と限定した。■ BS The S component has the effect of improving the hardenability of steel and ensuring strength and toughness, but when its content is 0, OO('1
If the content is less than 4%, the hardenability is insufficient and satisfactory toughness cannot be obtained, while if the content exceeds 0.0025%, it will adversely affect weldability. It was limited to 0.0004 to 0.0025.
■ Ｎ
Ｎ成分には、Ｔｉ成分とともにＴｉＮを形成して鋼基地
中に析出し、圧延組織を微細化する作用があるが、その
含有量がＯ，０Ｏ０５％未満では前記作用に所望の効果
が得られず、他方０．０１００％を越えて含有せしめる
とＳ成分と結合してＳ成分の焼入性向上効果を減じてし
まうようになることから、その含有量は０． ＯＯＯ５
〜０．０１００％と限定した。■N The N component has the effect of forming TiN together with the Ti component and precipitating in the steel matrix to refine the rolled structure, but if its content is less than 5% of O,0O, the desired effect will not be achieved. On the other hand, if it is contained in excess of 0.0100%, it will combine with the S component and reduce the hardenability improvement effect of the S component. OOO5
It was limited to ~0.0100%.
［相］ ｓｏ’１０Ｍ。[Phase] so’10M.
Ｍ成分には、脱酸作用および細粒化作用があるが、その
含有量が０．００５％未満では前記作用に所望の効果が
得られず、他方００９０％を越えて含有させると、非金
属介在物の量が増加し、鋼が脆化するようになることか
ら、その含有量を０． ＯＯ’ ５〜０、０９０％と限
定した。The M component has a deoxidizing effect and a grain refining effect, but if its content is less than 0.005%, the desired effects cannot be obtained, while if it is contained in an amount exceeding 0.090%, non-metal Since the amount of inclusions increases and the steel becomes brittle, the content should be reduced to 0. OO' was limited to 5-0, 090%.
ＯＣｕ、 Ｃｒ、 およびＭＯ
これらの成分には、鋼の焼入性を向上してマルテンサイ
トの生成を助ける均等な作用があるので、より一層の強
靭性が要求される場合に必要に応じて含有されるが、そ
の含有量がそれぞれ０．０５％未満では所望の強靭性向
上効果が得られず、他方それぞれ０．５０％を越えて含
有させると、細粒フェライトの生成を抑制されて靭性の
低下を招くようになることから、その含有量を０．０５
〜０．５０チと定めた。OCu, Cr, and MO These components have the same effect of improving the hardenability of steel and helping to generate martensite, so they may be added as necessary when even greater toughness is required. However, if the content is less than 0.05% of each, the desired effect of improving toughness cannot be obtained, while if the content exceeds 0.50% of each, the formation of fine ferrite is suppressed and the toughness is deteriorated. The content was reduced to 0.05 because it caused a decrease in
~0.50 chi.
＠Ｎ１．およびＣ。@N1. and C.
これらの成分には、鋼の靭性を改善する均等な作用があ
るので、より一層の靭性が要求される場合に必要に応じ
て含有されるが、その含有量がそれぞれ０．１４未満で
は所望の靭性向上効果が得られず、他方それぞれ１．、
Ｏ％を越えて含有させると、Ｎ１およびｃｏ元元素体が
高価なために経済的不利を招くことから、その含有量を
０．１〜１０％と定めた。These components have the same effect of improving the toughness of steel, so they are included as necessary when even greater toughness is required, but if their content is less than 0.14, the desired toughness cannot be achieved. No toughness improvement effect was obtained, and on the other hand, 1. ,
If the content exceeds 0%, it will cause an economic disadvantage because the N1 and co element bodies are expensive, so the content was set at 0.1 to 10%.
Ｑ■ Ｖ、およびＺｒ
これらの成分には、析出によって鋼の強度を向上させる
均等的作用があるので、より一層の強度が要求される場
合に必要に応じて含有されるが、その含有量がそれぞれ
０．０１４未満では所望の強度向上効果が得ら−れす、
他方それぞれ０．１５ ％を越えて含有せしめると靭性
劣化を来たすようになることから、その含有量をそれぞ
れ０．０１ ”−０，］、 ５係と限定した。Q■ V and Zr These components have a uniform effect of improving the strength of steel through precipitation, so they are included as necessary when even more strength is required, but their content is If each is less than 0.014, the desired strength improvement effect cannot be obtained.
On the other hand, if each content exceeds 0.15%, the toughness will deteriorate, so the content was limited to 0.01''-0,] and 5%, respectively.
（↓や Ｌａ、Ｃｅ、およびＣａ
これらの成分には、硫化物系非金属介在物の形態を制御
することにより、シャルピーの吸収エネルギーの著しい
向上および耐硫化物応力腐食割れ性を一段と向上させる
均等的作用があるので、必要に応じて含有されるが、そ
の含有量が、それぞれＯ，ＯＯＯ” ５％未満では所望
の介在物の球状化効果が得られず、他方それぞれ０．
ＯＯ５％を越えて含有させると、非金属介在物の量が増
加しこれらの性能が損なわれる傾向が現われるようにな
ることから、その含有量をそれぞれＯ○００５〜０．０
２０％と限定した。(↓, La, Ce, and Ca) These components contain uniform additives that significantly improve Charpy absorption energy and further improve sulfide stress corrosion cracking resistance by controlling the morphology of sulfide-based nonmetallic inclusions. However, if the content is less than 5% each, the desired effect of spheroidizing the inclusions cannot be obtained;
If the content exceeds OO5%, the amount of nonmetallic inclusions will increase and the performance of these will tend to be impaired, so the content should be increased from 0005 to 0.0.
It was limited to 20%.
■）圧延条件
■ 加熱温度：９００〜１１７０℃
加熱温度が９００℃未満ということは、鋼のオーステナ
イト化する温度（ＡＣｓ点）に達していないということ
であり、所望の圧延組織を得ることができないのに対し
て、加熱温度が１１．７０ ℃を越えると鋼材組織が粗
粒化し、靭性不良を来たすようになることから、加熱温
度を９００〜１ ］−７０℃と定めた。■) Rolling conditions ■ Heating temperature: 900 to 1170°C If the heating temperature is less than 900°C, it means that the temperature at which the steel becomes austenitic (ACs point) has not been reached, and the desired rolled structure cannot be obtained. On the other hand, if the heating temperature exceeds 11.70°C, the steel structure becomes coarse grained, resulting in poor toughness, so the heating temperature was set at 900-1]-70°C.
■ 圧下条件：９００℃以下で５０４以上圧下時の温度
が９００℃を越えたシ、その累積圧下率が５０チ未満で
ある場合には、歪をもった微Ｍな、ｉ−ステナイト粒を
作ることができず、したがって、細粒フェライトの生成
を促進することができなくなる。つまり、仕上圧延後の
空冷またはある程度の強冷によって微細なフェライトを
得、その後の焼入れで、微細に分散し及マルテンサイト
を得るためには、９ｏｏ℃以下の温度での５０チ以上の
累積圧下率の圧延が不可欠であるので、圧下条件を上記
のように限定した。■ Reduction conditions: If the temperature at the time of reduction of 504 or more exceeds 900℃ at 900℃ or less, and the cumulative reduction rate is less than 50℃, it will create distorted, micro-M, i-stenite grains. Therefore, it becomes impossible to promote the formation of fine-grained ferrite. In other words, in order to obtain fine ferrite by air cooling or strong cooling to a certain extent after finish rolling, and to obtain finely dispersed martensite by subsequent quenching, cumulative rolling of 50 inches or more at a temperature of 90°C or less is required. Since rolling at a certain rate is essential, the rolling conditions were limited as described above.
■ 仕上温度
圧延仕上温度が８００℃を越えると圧延組織の細粒化が
不十分であシ、他方その温度が６．ＬＯ℃未満では二相
域圧延の度合が過大となって、靭ｔ’１並びに延性の低
下を来たすようになることがら、その温度を８００〜６
５０℃と定めた。■ Finishing temperature If the rolling finishing temperature exceeds 800°C, the rolling structure will not be sufficiently refined; If the temperature is lower than LO℃, the degree of rolling in the two-phase region becomes excessive, resulting in a decrease in toughness t'1 and ductility.
The temperature was set at 50°C.
■）冷却条件
圧延仕上後の冷却を、空冷または４℃／秒を越えない加
速冷却としたのは、これらの値よりも速い冷却速度では
フェライト変態が抑制されてしまって、微細なフェライ
ト組織を得ることができなくなるからである。特に、４
℃／秒を越えない程度の冷却速度を上限としたのは、板
厚の厚いものに対しての焼入れまでの冷却を促進して能
率の向上を図るという理由からであるが、この冷却速度
を越えた場合には、前述のようにフェライト変態がスム
ーズに起らなくなるのである。■) Cooling conditions Air cooling or accelerated cooling not exceeding 4°C/sec was used for cooling after rolling finishing, as cooling rates faster than these values would inhibit ferrite transformation and cause a fine ferrite structure to form. Because you won't be able to get it. In particular, 4
The reason for setting the cooling rate as an upper limit of ℃/second is to promote cooling of thick plates until quenching and to improve efficiency. If it exceeds this, ferrite transformation will not occur smoothly as described above.
■）焼入温度
Ａｒ１点である６００℃を越える温度がら焼入れを行な
うと、フェライト変態が十分に進行せずに単なる焼入組
織になってしまって良好な靭性を得ることができなくな
る。他方、３５０℃未満の温度では、いわゆるＭｓ点以
下であるので焼入れの効果が十分でなくなる。したがっ
て、焼入温度を６００〜３５０℃と定めた。(2) If quenching is performed at a temperature exceeding 600° C., which is the quenching temperature Ar1 point, ferrite transformation will not proceed sufficiently and the structure will become a mere quenched structure, making it impossible to obtain good toughness. On the other hand, if the temperature is lower than 350°C, the hardening effect will not be sufficient because the temperature is below the so-called Ms point. Therefore, the quenching temperature was set at 600 to 350°C.
ついで、この発明を実施例により比較例と対比しながら
説明する。Next, the present invention will be explained by examples and in comparison with comparative examples.
実施例 １
この例では、仕上圧延後の焼入温度が鋼材の機械的・物
理的性質に与える影響を比較した。Example 1 In this example, the influence of the quenching temperature after finish rolling on the mechanical and physical properties of steel materials was compared.
まず、第１表に示すような本発明方法を満足する化学成
分組成を有し、厚みが１５０＋ｍのスラブを常法によっ
て製造した。First, a slab having a chemical composition satisfying the method of the present invention as shown in Table 1 and having a thickness of 150+ m was manufactured by a conventional method.
第 １ 表
つぎに、このスラブを１０５０℃に加熱保持した後粗圧
延を行ない、ついで温度が９００℃をト廻った時点でス
ラブ厚７５」より６７係の圧平゛ｆで圧延を施した。そ
して、７４０℃にて圧延を終了し、引続いて空冷した後
、第２表に示したような各種焼入温度で焼入れして、板
厚二２５ｍｍの鋼板を得た。Table 1 Next, this slab was heated and held at 1050° C. and then rough rolled, and then, when the temperature reached 900° C., it was rolled at a rolling rate f of 67 from a slab thickness of 75”. Then, rolling was completed at 740° C., followed by air cooling, and then quenching at various quenching temperatures as shown in Table 2 to obtain steel plates with a thickness of 225 mm.
このようにして得られた各種鋼板について、強度および
靭性を比較するためにその機械的・物理的性質を測定し
、その結果を第２表に併せて記載した。The mechanical and physical properties of the various steel plates thus obtained were measured in order to compare their strength and toughness, and the results are also listed in Table 2.
第 ２ 表
第２表に示した結果からも明らかなように、焼入温度が
７００〜６３０℃と本発明の範囲よりも高い場合の焼入
材２及び３は強度が最□も高い値を示すけれども、シャ
ルピー破面遷移温度（ｖＴｓ）。Table 2 As is clear from the results shown in Table 2, quenched materials 2 and 3 with a quenching temperature of 700 to 630°C, which is higher than the range of the present invention, have the highest strength values. Although shown, Charpy fracture transition temperature (vTs).
ＤＷＴＴ落下試落下試験８外
ＦＡ’ｒＴ ）で表わされるところの靭性が著しく劣っ
ていることがわかる。これは、ｒ→α変態が完了しない
うちに焼入れを行なったために細粒フェライトの生成が
阻止され、ベイナイトおよびマルテンサイトの量が著し
く増したためである。It can be seen that the toughness as expressed by DWTT Drop Test 8 (FA'rT) is significantly inferior. This is because quenching was performed before the r→α transformation was completed, which prevented the formation of fine grain ferrite and significantly increased the amount of bainite and martensite.
他方、焼入温度が、本発明の範囲であるＡｒ１変態点以
下の６００〜３５０℃であった焼入材４〜７は、圧延後
空冷材１に比較して１０ｋｇ／−以上の強度上昇が得ら
れるにもかかわらず、靭性の劣化がほとんどみられなか
った。On the other hand, quenched materials 4 to 7 whose quenching temperature was 600 to 350°C below the Ar1 transformation point, which is the range of the present invention, showed a strength increase of 10 kg/- or more compared to air-cooled material 1 after rolling. Despite this, almost no deterioration in toughness was observed.
° 実施例 ２
この例では、鋼板製造の際の加熱・圧延・冷却条件が、
鋼材の機械的・物理的性質に与える影響を比較した。° Example 2 In this example, the heating, rolling, and cooling conditions during steel sheet production are as follows:
The effects on the mechanical and physical properties of steel materials were compared.
まず、実施例１における第１表に示したの゛と同様の、
本発明方法を満足する化学成分組成を有し、厚みが１５
０朋のスラブを用意した。First, similar to that shown in Table 1 in Example 1,
It has a chemical composition that satisfies the method of the present invention and has a thickness of 15
A slab of 0.0 was prepared.
このスラブの１つを１，１０５０℃に加熱保持した後、
温度が９００℃を下廻った時点で６７％の圧下率の圧延
を施し、ついで７４０℃にて圧延を終了してから引続い
て空冷を施し、５５０℃の温度から焼入れすることによ
って板厚：２５ｍｍの鋼板を得た。このときの条件を本
発明の標準条件とし、それによって得られた試料番号５
の試料の機械的・物理的性質を第３表にあらためて示し
た。After heating and holding one of these slabs at 1,1050°C,
When the temperature drops below 900°C, it is rolled at a reduction rate of 67%, then after finishing the rolling at 740°C, it is subsequently air cooled and quenched from a temperature of 550°C to a plate thickness of 25 mm. steel plate was obtained. The conditions at this time were taken as the standard conditions of the present invention, and sample number 5 obtained thereby
The mechanical and physical properties of the samples are shown in Table 3.
つぎに、上記スラブの別のものについて、それぞれ、加
熱温度．９００℃以下における圧Ｆ、率。Next, for each of the above slabs, set the heating temperature. Pressure F, rate below 900°C.
圧延仕上温度，および仕上後の冷却速度を第３表に示し
たように変えたほかは、標準条件と同様の条件で圧延を
行な−い、５５０”Ｃの温度から焼入れをすることによ
って試料番号９〜１４の鋼板を得た。これらの機械的・
物理的性質も第３表に併せて示した。The specimens were prepared by rolling under the same conditions as the standard conditions, except that the finishing temperature and cooling rate after finishing were changed as shown in Table 3, and quenching was performed from a temperature of 550"C. Steel plates numbered 9 to 14 were obtained.
Physical properties are also shown in Table 3.
第３表に示した結果からも、加熱・圧延・冷却の条件が
本発明方法の範囲を外れると、いずれも低温靭性が著し
く悪化することが明白である。From the results shown in Table 3, it is clear that when the heating, rolling, and cooling conditions are out of the range of the method of the present invention, the low-temperature toughness deteriorates significantly.
特に、圧延仕上から焼入れまでの間の加速冷却は、板厚
が大きいと焼入までに時間がかかるのでこれを防止する
ために講じられる手段であるが、これによって冷却速度
が速くなりすぎると、実質的に圧延後直ちに焼入れした
のと同じこととなって靭性劣化を招くものであることが
、試料番号１４の靭性値と試料番号１３の靭性値を比較
することによって１男白である。In particular, accelerated cooling between rolling finishing and quenching is a measure taken to prevent this, since it takes time to quench when the plate thickness is large, but if the cooling rate becomes too fast as a result of this, Comparing the toughness values of Sample No. 14 and Sample No. 13, it is clear that this is essentially the same as quenching immediately after rolling, leading to deterioration of toughness.
実施例 ３
この例では、鋼板製造の際の化学成分組成が機械的・物
理的性質に及ぼす影響を比較したものである。Example 3 In this example, the influence of chemical composition on mechanical and physical properties during steel sheet production is compared.
通常の溶解法により、それぞれ第４表に示される化学成
分組成をもった鋼を溶製し、通常の条（’＋で鋳造し、
得られたスラブを１０５０℃に加熱保持した後粗圧延を
行ない、ついでスラブ厚５７朋にて８５０℃よシロ７チ
の圧下率にて圧延を再開し、７００℃で圧延を終了後空
冷を行ない、５５０℃の温度より水焼入れし、得られた
板厚：１９ｍ。Steels having the chemical compositions shown in Table 4 are melted using normal melting methods, and cast into normal strips ('+).
After heating and holding the obtained slab at 1050°C, rough rolling was performed, and then rolling was restarted at 850°C with a rolling reduction of 7 cm at the slab thickness, and after finishing rolling at 700°C, air cooling was performed. , water quenched at a temperature of 550°C, resulting in a plate thickness of 19 m.
の鋼板について、それぞれ、その機械的・物理的性質を
測定した。これらの結果も第４表に併せて示した。The mechanical and physical properties of each steel plate were measured. These results are also shown in Table 4.
第４表に示される結果から、本発明材２１−−５０は、
いずれも７０ｋｇ／−級の引張強さを示すとともに、高
い低温靭性値を具備しているのに対して、比較材５１〜
６３にみられるように成分組成のいずれかでもこの発明
の範囲から外れると前記特性のうち少なくともいずれか
の特性が劣ったものになることが明らかである。From the results shown in Table 4, the present invention materials 21--50 are as follows:
All of them exhibit tensile strength of 70 kg/- class and have high low temperature toughness values, while comparative materials 51~
As seen in No. 63, it is clear that if any of the component compositions deviates from the scope of the present invention, at least one of the above characteristics will be inferior.
上述のように、この発明の方法によれば、溶接性に好適
である低い炭素量を確保できるとともに、強度および靭
性が、それぞれ、引−張り強さ：６０〜８０ｋｇ／−お
よびシャルピー破面遷移温度ニー１００℃以下程度と優
れた値を示す鋼を製造することができ、したがってこの
鋼を苛酷な環境条件下の油田やガス田の開発の際、ライ
ンパイプとして用いた場合に著しく優れた性能を発揮す
るのである。As described above, according to the method of the present invention, it is possible to ensure a low carbon content suitable for weldability, and the strength and toughness are improved by tensile strength: 60 to 80 kg/- and Charpy fracture transition, respectively. It is possible to manufacture steel that exhibits an excellent temperature knee of about 100°C or less, and therefore, when used as line pipe in the development of oil fields and gas fields under harsh environmental conditions, it has extremely excellent performance. It shows that.
また、この発明の方法で得られた高張力鋼板をＡｃｌ変
態点以下に焼戻し処理することは、その鋼の特性を何ら
損ねるものではなく、むしろ靭性および耐硫化水素割れ
性等の面で改善作用が期待されるものである。Furthermore, tempering the high-strength steel sheet obtained by the method of the present invention to a temperature below the ACl transformation point does not impair the properties of the steel in any way, but rather improves its toughness and resistance to hydrogen sulfide cracking. is expected.
昭和５８年 ３月１７１１
特許庁長官 若 杉 和 夫
１、事件の表示
特願昭５７−９３７２７ 号
２、発明の名称
直接焼入法による強＠尚張カ鋼板の製造法３、補正をす
る者
代表者 熊 谷 典 文
４、代 理 人
自 発
補正の内容
（１） 明細書中、特許請求の範囲を別紙の通シに補
正する。March 1711, 1981 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1, Indication of the case, Patent Application No. 1987-93727 2, Name of the invention: Method for producing strong steel sheets by direct quenching method 3, Person making amendments Representative Noriyuki Kumagai 4. Contents of the agent's voluntary amendment (1) The scope of claims in the specification is amended in a separate notice.
（■ 明細書、第６頁、第１９行に
［６００〜３５０℃（Ｍｓ点より上）から］とあるを、
１’−Ａｒ、変態点近傍〜Ｍｓ点の温Ｉｒ−範囲から」
と訂正する。(■ In the specification, page 6, line 19, it says [from 600 to 350°C (above the Ms point)], 1'-Ar, from the temperature Ir-range from near the transformation point to the Ms point.''
I am corrected.
（３）明細書、第８頁、第２行に １６００〜３５０℃の」 とあるな、 ｌ Ａｒ、変態点近傍〜Ｍｓ点の」 と訂正する。(3) Specification, page 8, line 2 1600-350℃ That's what it says. l Ar, near the transformation point ~ Ms point'' I am corrected.
（４） 明細書、第９頁、第１８行に「６００〜３５
０°Ｃの範囲に」
とあるを、
［Ａｒ、変態点近傍〜Ｍｓ点の温度範囲に」と訂正する
。(4) Specification, page 9, line 18: “600-35
"In the range of 0°C" should be corrected to "In the temperature range of Ar, near the transformation point to the Ms point."
（５） 明細書、第１Ｏ頁、第７〜８行に「Ａｒ、点
以下（６００°Ｃ以下）から」とあるを、
［フェライト変態のほぼ終了に近いＡｒ、点近傍以下の
温度から−１
と訂正する。(5) In the specification, page 1O, lines 7-8, the phrase "from Ar, below the point (600°C or less)" has been replaced with [from the Ar temperature near the end of the ferrite transformation (600°C or less)]. Correct it as 1.
（０明細書、第１８頁、第１１行に
「Ａｒ、点である６００°Ｃを越える温度から１とある
な、
「γ−α変態が未だ進行中のＡｒ、点より高い鋼のＡｒ
、点は成分、冷却速度によって変動するが、本発明鋼で
は６５０〜６００ ”Ｃと考えられるその温度から」
と訂正する。(In the 0 specification, page 18, line 11, it says ``1 from the temperature exceeding 600°C, which is the point of Ar.''
, the point varies depending on the composition and cooling rate, but for the steel of the present invention, the temperature is considered to be 650 to 600 "C".
（η 明細書、第１８頁、第１４行に
［他方、３５０℃未満の」
とあるな、
「他方、ＭｉＥ点温度以下、即ち平均的には３５０℃未
満の」
と訂正する。(η In the specification, page 18, line 14, it says [on the other hand, less than 350°C]. Corrected to ``On the other hand, below the MiE point temperature, that is, on average, less than 350°C.''
（０明細書、第１８頁、第１７行に
１６００〜３５０ ”Ｃと定めた。」
とあるを、
［Ａｒ、変態点近傍〜Ｍｓ点の温度範囲と定めた。］と
訂正する。(In the 0 specification, page 18, line 17, it was set as 1600 to 350"C." is corrected to [The temperature range is set as Ar, near the transformation point to the Ms point.]
（９） 明細書、第２０頁、下から４行目に「７００
〜６３０℃と本発明の範囲」
とあるな、
１７００〜６３０°Ｃ（本発明鋼のＡｒ、点は約６００
℃）と本発明の範囲」
と訂正する
以上
「２、特許請求の範囲
Ｃ：０．００３〜０１００％、Ｓｉ：０．８５％以下、
Ｍｎ ：１．０〜３，０％、ｐ：０．０３％以下、Ｓ
：０．００９％以下。(9) Specification, page 20, 4th line from the bottom, “700
~630°C and the range of the present invention.'' 1700~630°C (Ar of the present invention steel, the point is approximately 600°C)
℃) and the scope of the present invention" is corrected as "2. Claim C: 0.003 to 0100%, Si: 0.85% or less,
Mn: 1.0-3.0%, p: 0.03% or less, S
: 0.009% or less.
Ｎｂ：０．００８〜０．１８０％、Ｔｉ：０．００４〜
０．０４０％。Nb: 0.008~0.180%, Ti: 0.004~
0.040%.
Ｂ：０．０００４〜０．００２５％、 Ｎ ：０．
０００５〜０．０１００％、 ｓｏｌ、ＡＱ ：
０．００５〜０．０９０ ％。B: 0.0004-0.0025%, N: 0.
0005~0.0100%, sol, AQ:
0.005-0.090%.
を含有するとともに、必要に応じて、さらに、Ｃｕ、
Ｃｒ、およびＭｏの１種以上： ０．０５〜０．５０％
。In addition to containing, if necessary, further Cu,
One or more of Cr and Mo: 0.05 to 0.50%
.
Ｎｉ、およびＣｏの１種以上：０．１〜１．０％。One or more of Ni and Co: 0.1 to 1.0%.
■、およびＺｒの１種以上： ０．０１〜０．１５％。(1), and one or more types of Zr: 0.01 to 0.15%.
Ｌａ、 Ｃｅ、およびＣａの１種以上： ０．０００５
〜０．０２０％。One or more of La, Ce, and Ca: 0.0005
~0.020%.
を単独または複合して含有し、
Ｆｅおよび不可避不純物：残り、
（以上重量％〕からなる鋼を、９００〜１１７０℃に加
熱した後、少なくとも９００℃以Ｆの累積圧下率が５０
％以上で、かつ仕上温度が８００〜６５０℃の圧延を施
し、圧延仕上後、空冷または囲より直接焼入れすること
を特徴とする強靭前張力鋼板の製造法。」After heating a steel containing Fe and unavoidable impurities (at least % by weight) alone or in combination to 900 to 1170°C, the cumulative rolling reduction rate of at least 900°C is 50°C.
% or more and at a finishing temperature of 800 to 650° C., and after finishing the rolling, air cooling or direct quenching from the surroundings is performed. ”
Claims (1)
Ｍｎ二１．０〜３０％、Ｐ：０．０３係以下、 Ｓ
：０．００９チ以下、Ｎｂ：０．００８〜０１８０チ、
Ｔｉ：０．００４〜００４０％−、Ｂ ：Ｏ，ＯＯＯ今
〜Ｏ，ＯＯ２５チ、 Ｎ、： ０．０００５〜０．０１
００ ％、 ５ｏＬＮｌ ： ０．００５〜０．０９０
％。 を含有するとともに、必要に応じて、さらに、Ｃｕ、Ｃ
ｒ、およびＭｏの１種以上：０．０５〜０．５０チ。 Ｎｉ、およびｃｏの１種以上：Ｏ，１〜１．０％。 ｖ９およびＺｒの１種以上：０．０１〜０．１５％。 Ｌａ、Ｃｅ、およびＣａの１種以上二〇０００５〜０、
ＯＯ２０％。 を単独または複合して含有し、 Ｆｅおよび不可避不純物二残り、 （以上重量％）からなる鋼を、９００〜１１７０℃に加
熱した後、少なくとも９００℃以下の累積圧下率が５０
％以上で、かつ仕上温度が８００〜６５０℃の圧延を施
し、圧延仕上後、空冷または４℃／秒を越えない加速冷
却により６００〜３５０℃の範囲に冷却してから、この
温度範囲よシ直接焼入れすることを特徴とする強靭高張
力鋼板の製造法。[Claims] C: 0003 to ○, 100%, Si: 0.85% or less,
Mn2 1.0-30%, P: 0.03 or less, S
: 0.009 inch or less, Nb: 0.008 to 0180 inch,
Ti: 0.004-0040%-, B: O, OOO now ~ O, OO25 Chi, N: 0.0005-0.01
00%, 5oLNl: 0.005-0.090
%. and, if necessary, further contain Cu, C
r, and one or more types of Mo: 0.05 to 0.50 h. One or more of Ni and co: O, 1 to 1.0%. One or more of v9 and Zr: 0.01 to 0.15%. one or more of La, Ce, and Ca 200005-0,
OO20%. After heating a steel containing Fe and unavoidable impurities (at least 2% by weight) alone or in combination to 900 to 1170°C, the cumulative rolling reduction rate below 900°C is at least 50%.
% or more and at a finishing temperature of 800 to 650°C, and after finishing the rolling, cool to a range of 600 to 350°C by air cooling or accelerated cooling not exceeding 4°C/sec, and then A method for producing strong, high-tensile steel sheets that is characterized by direct quenching.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9372782A JPS58210125A (en) | 1982-06-01 | 1982-06-01 | Production of strong and tough high tensile steel plate by direct hardening method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9372782A JPS58210125A (en) | 1982-06-01 | 1982-06-01 | Production of strong and tough high tensile steel plate by direct hardening method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58210125A true JPS58210125A (en) | 1983-12-07 |
| JPH0413406B2 JPH0413406B2 (en) | 1992-03-09 |
Family
ID=14090441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9372782A Granted JPS58210125A (en) | 1982-06-01 | 1982-06-01 | Production of strong and tough high tensile steel plate by direct hardening method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58210125A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4615749A (en) * | 1984-02-18 | 1986-10-07 | Kawasaki Steel Corporation | Cold rolled dual-phase structure steel sheet having an excellent deep drawability and a method of manufacturing the same |
| US4990196A (en) * | 1988-06-13 | 1991-02-05 | Nippon Steel Corporation | Process for manufacturing building construction steel having excellent fire resistance and low yield ratio |
| JPH0559171B2 (en) * | 1984-07-30 | 1993-08-30 | Nippon Steel Corp | |
| JP2007239090A (en) * | 2006-02-08 | 2007-09-20 | Kobe Steel Ltd | Thick steel plate superior in toughness at super high-heat-input haz and in low-temperature toughness of base metal |
| US7682467B2 (en) | 2004-01-21 | 2010-03-23 | Kobe Steel, Ltd. | High strength hot rolled steel sheet superior in workability, fatigue property, and surface quality |
| JP2010248599A (en) * | 2009-04-20 | 2010-11-04 | Kobe Steel Ltd | Thick steel plate with low yield ratio and high toughness |
| JP2011195961A (en) * | 2011-04-28 | 2011-10-06 | Jfe Steel Corp | HIGH TENSILE STRENGTH STEEL SHEET HAVING EXCELLENT WORKABILITY AND TENSILE STRENGTH OF AT MOST 628 MPa |
| US9650690B2 (en) | 2008-06-13 | 2017-05-16 | Nippon Steel & Sumitomo Metal Corporation | High-strength steel sheet and method of producing molten steel for high-strength steel sheet |
| CN114752852A (en) * | 2022-03-23 | 2022-07-15 | 安阳钢铁股份有限公司 | Preparation method for producing low-alloy high-strength wear-resistant steel by adopting DQ (data-transfer-welding) process |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5544590A (en) * | 1978-09-26 | 1980-03-28 | Kawasaki Steel Corp | Production of high tensile thin steel plate of superior cold workability |
-
1982
- 1982-06-01 JP JP9372782A patent/JPS58210125A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5544590A (en) * | 1978-09-26 | 1980-03-28 | Kawasaki Steel Corp | Production of high tensile thin steel plate of superior cold workability |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4615749A (en) * | 1984-02-18 | 1986-10-07 | Kawasaki Steel Corporation | Cold rolled dual-phase structure steel sheet having an excellent deep drawability and a method of manufacturing the same |
| JPH0559171B2 (en) * | 1984-07-30 | 1993-08-30 | Nippon Steel Corp | |
| US4990196A (en) * | 1988-06-13 | 1991-02-05 | Nippon Steel Corporation | Process for manufacturing building construction steel having excellent fire resistance and low yield ratio |
| US7682467B2 (en) | 2004-01-21 | 2010-03-23 | Kobe Steel, Ltd. | High strength hot rolled steel sheet superior in workability, fatigue property, and surface quality |
| JP2007239090A (en) * | 2006-02-08 | 2007-09-20 | Kobe Steel Ltd | Thick steel plate superior in toughness at super high-heat-input haz and in low-temperature toughness of base metal |
| US9650690B2 (en) | 2008-06-13 | 2017-05-16 | Nippon Steel & Sumitomo Metal Corporation | High-strength steel sheet and method of producing molten steel for high-strength steel sheet |
| JP2010248599A (en) * | 2009-04-20 | 2010-11-04 | Kobe Steel Ltd | Thick steel plate with low yield ratio and high toughness |
| JP2011195961A (en) * | 2011-04-28 | 2011-10-06 | Jfe Steel Corp | HIGH TENSILE STRENGTH STEEL SHEET HAVING EXCELLENT WORKABILITY AND TENSILE STRENGTH OF AT MOST 628 MPa |
| CN114752852A (en) * | 2022-03-23 | 2022-07-15 | 安阳钢铁股份有限公司 | Preparation method for producing low-alloy high-strength wear-resistant steel by adopting DQ (data-transfer-welding) process |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0413406B2 (en) | 1992-03-09 |
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