JPH05222450A - Production of high tensile steel plate - Google Patents
Production of high tensile steel plateInfo
- Publication number
- JPH05222450A JPH05222450A JP2503092A JP2503092A JPH05222450A JP H05222450 A JPH05222450 A JP H05222450A JP 2503092 A JP2503092 A JP 2503092A JP 2503092 A JP2503092 A JP 2503092A JP H05222450 A JPH05222450 A JP H05222450A
- Authority
- JP
- Japan
- Prior art keywords
- less
- tempering
- strength
- quenching
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は焼き入れ焼き戻しにより
生産性の高い強度、靱性に優れた低降伏比高張力鋼板製
造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high yield steel plate having a low yield ratio and excellent in strength and toughness with high productivity by quenching and tempering.
【０００２】[0002]
【従来の技術】近年、建築用構造物等に使用される鋼材
（鋼板、鋼管、形鋼など）においては耐震性の優れた低
降伏比高張力鋼板が求められている。このような要求に
対して、例えば特開昭５５−４１９２７号公報あるいは
特開昭５５−９７４２５号公報記載の方法が提案されて
いる。前者の方法は制御圧延、制御冷却を用いた方法で
あり、後者の方法は焼き入れ、焼き戻しによる方法であ
るが、いずれの場合も引っ張り強度が６０ｋｇｆ／ｍｍ
2 級の鋼に適用される方法であり、６０ｋｇｆ／ｍｍ2
を超える鋼に対して一般的に適用されるものではない。2. Description of the Related Art In recent years, steel materials (steel plates, steel pipes, shaped steels, etc.) used for building structures and the like have been required to have low yield ratio and high tensile steel plates having excellent earthquake resistance. In order to meet such demand, for example, the methods described in JP-A-55-41927 or JP-A-55-97425 have been proposed. The former method is a method using controlled rolling and controlled cooling, and the latter method is a method by quenching and tempering. In both cases, the tensile strength is 60 kgf / mm.
It is a method applied to the second grade steel, 60 kgf / mm 2
It is not generally applied to steels exceeding 100.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、これら従来
法の問題点を排除し、６０ｋｇｆ／ｍｍ2 を超える強度
の鋼に対しても適用できる強度、靱性に優れた低降伏比
高張力鋼板の容易なる製造方法を提供することにある。DISCLOSURE OF THE INVENTION The present invention eliminates the problems of these conventional methods and can be applied to steel having a strength exceeding 60 kgf / mm 2 and has a low yield ratio and a high tensile strength steel plate excellent in strength and toughness. Another object of the present invention is to provide an easy manufacturing method.
【０００４】[0004]
【課題を解決するための手段】本発明の要旨とするとこ
ろは （１）重量％で、 Ｃ ：０．０２〜０．５％、 Ｍｎ：０．０２〜１０．０％、 Ｓｉ：０．０１〜１．０％、 Ａｌ：０．１％以下、 を含有し、残部がＦｅおよび不可避的不純物からなる鋼
板を直接焼き入れあるいは再加熱後に焼き入れし、その
後、焼き戻しを行って高張力鋼板を製造する方法におい
て、焼き入れ後の金属組織が主にベイナイト、マルテン
サイトあるいはこの混合組織であって、焼き戻し時の昇
温速度を１℃／秒以上、焼き戻し温度をＡｃ1 点以上の
温度とし、さらに保持を１５分以内で終了し、その後、
放冷もしくは強制冷却を行うことを特徴とする生産性の
高い高強度、高靱性低降伏比高張力鋼板の製造方法。 （２）重量％で、 Ｃ ：０．０２〜０．５％、 Ｍｎ：０．０２〜１０．０％、 Ｓｉ：０．０１〜１．０％、 Ａｌ：０．１％以下、 が基本成分であり、 Ｍｏ：３．０ ％以下、 Ｎｉ：１０．０ ％以下、 Ｃｒ：３．０ ％以下、 Ｖ ：０．１ ％以下、 Ｎｂ：０．１ ％以下、 Ｔｉ：０．１ ％以下、 Ｂ ：０．００３ ％以下、 Ｃｕ：１０．０ ％以下、 Ｃｏ：１０．０ ％以下、 Ｗ ：３．０ ％以下 のいずれか１種、または２種以上をさらに含有する残部
がＦｅおよび不可避的不純物からなる鋼板を直接焼き入
れあるいは再加熱後に焼き入れし、その後焼き戻しを行
って高張力鋼板を製造する方法において、焼き入れ後の
組織が主にマルテンサイト、ベイナイトあるいはこの混
合組織であって、焼き戻し時の昇温速度を１℃／秒以
上、焼き戻し温度をＡｃ1 点以上の温度とし、さらに保
持時間を１５分以内で終了し、その後放冷もしくは強制
冷却を行うことを特徴とする生産性の高い高強度、高靱
性低降伏比高張力鋼板の製造方法にある。これにより焼
き戻しマルテンサイトあるいは焼き戻しベイナイトの微
細な金属組織状態を損なうこと無く、その組織中に微細
なマルテンサイト、残留オーステナイトあるいはセメン
タイトを分散させ、強度、靱性にすぐれた低降伏比高張
力鋼板を製造し得る。The gist of the present invention is as follows: (1)% by weight, C: 0.02 to 0.5%, Mn: 0.02 to 10.0%, Si: 0. 01-1.0%, Al: 0.1% or less, and the remaining part is made of Fe and inevitable impurities. The steel plate is directly quenched or reheated, and then tempered to obtain high tensile strength. In the method for producing a steel sheet, the metal structure after quenching is mainly bainite, martensite or a mixed structure thereof, and the temperature rising rate during tempering is 1 ° C./sec or more and the tempering temperature is Ac 1 point or more. Temperature, and hold for less than 15 minutes, then
A method for producing a high-productivity, high-strength, high-toughness, low-yield-ratio, high-strength steel sheet characterized by performing cooling or forced cooling. (2) By weight%, C: 0.02 to 0.5%, Mn: 0.02 to 10.0%, Si: 0.01 to 1.0%, Al: 0.1% or less are basic. Mo: 3.0% or less, Ni: 10.0% or less, Cr: 3.0% or less, V: 0.1% or less, Nb: 0.1% or less, Ti: 0.1% Hereinafter, B: 0.003% or less, Cu: 10.0% or less, Co: 10.0% or less, W: 3.0% or less, or the balance further containing at least two types is Fe. And a method of manufacturing a high-strength steel sheet by directly quenching or reheating a steel sheet made of unavoidable impurities, and then tempering it to produce a high-strength steel sheet, where the structure after quenching is mainly martensite, bainite or a mixed structure thereof. And the temperature rising rate during tempering is 1 ° C / sec or more, and the tempering temperature is Was the Ac 1 point or higher, further retention time was completed within 15 minutes, a high strength of productivity and performing subsequent cooling or forced cooling, production of high tenacity low yield ratio high-tensile steel plate On the way. As a result, fine martensite, retained austenite or cementite is dispersed in the microstructure of tempered martensite or tempered bainite without impairing the fine metallographic state, and low yield ratio and high strength steel plate with excellent strength and toughness. Can be manufactured.
【０００５】以下、本発明について詳細に説明する。本
発明の基本となる考え方は以下の通りである。まず、金
属学的な見地から直接焼き入れを含む焼き入れ、焼き戻
しで製造される鋼の強度、靱性は第一に金属組織の微細
さに依存している。通常、焼き入れ後の鋼の金属組織は
マルテンサイトとベイナイトからなり、その結晶粒は微
細である。従って、その強度は高い。しかしながら、焼
き入れままの金属組織は過飽和の炭素原子を多く含有し
ており、強度は高いが延性や靱性が充分ではない。そこ
で、通常、焼き入れ後には焼き戻し処理が行われる。一
般に焼き戻し処理は焼き戻し処理を行う温度に設定され
た熱処理炉内に鋼板を挿入し、Ａｃ1 点以下の所定の温
度に到達せしめ、その後に数１０分程度の保持を行うこ
とで行われており、昇温の為の時間を含めると極めて長
時間の焼き戻し処理が行われる。このため焼き戻し後の
金属組織は焼き戻しマルテンサイトあるいは焼き戻しベ
イナイトとなる。このような鋼の降伏比は、焼き戻しに
より析出したセメンタイト等の炭化物が可動転位を固着
するために降伏強度が高く、９０％を超えることが多
い。The present invention will be described in detail below. The basic idea of the present invention is as follows. First, from a metallurgical point of view, the strength and toughness of steel produced by quenching including direct quenching and tempering depend primarily on the fineness of the metal structure. Usually, the metal structure of steel after quenching consists of martensite and bainite, and its crystal grains are fine. Therefore, its strength is high. However, the as-quenched metallographic structure contains many supersaturated carbon atoms and has high strength but insufficient ductility and toughness. Therefore, a tempering process is usually performed after quenching. Generally, tempering is performed by inserting a steel plate into a heat treatment furnace set to a temperature for performing tempering, allowing it to reach a predetermined temperature of Ac 1 point or less, and then holding it for several tens of minutes. Therefore, the tempering process is performed for an extremely long time when the time for raising the temperature is included. Therefore, the metal structure after tempering becomes tempered martensite or tempered bainite. The yield ratio of such steel is high because the carbides such as cementite precipitated by tempering fix the mobile dislocations, and the yield ratio is high and often exceeds 90%.
【０００６】一方、焼き入れままのマルテンサイトや残
留オーステナイトは結晶粒内に転位を多く含有するなど
のために降伏強度が低く、低降伏比となる。さらに残留
オーステナイト部分にはマルテンサイト（フェライト）
との固溶度の差に基づいて、固溶原子を吸収し、マルテ
ンサイト中で降伏強度の上昇をもたらす固溶原子等を低
減する効果もある。そこで鋼を低降伏比とするには、残
留オーステナイトを生成せしめることや焼き戻し処理中
にマルテンサイトや残留オーステナイトの転位の回復を
制御することが必要であると思われる。従って、焼き戻
し処理温度をＡｃ1 点温度以上とし金属組織の一部をオ
ーステナイト化し、冷却中にそのまま残留させるか再び
マルテンサイトにすることによって、焼き戻しマルテン
サイト、焼き戻しベイナイトとの混合組織を形成し、降
伏比の低い鋼板を製造できると考えられる。On the other hand, the as-quenched martensite and retained austenite have a low yield strength and a low yield ratio because they contain many dislocations in the crystal grains. Furthermore, martensite (ferrite) is present in the retained austenite part.
It also has an effect of absorbing solid solution atoms based on the difference in solid solubility between and, and reducing solid solution atoms and the like that cause an increase in yield strength in martensite. Therefore, in order to reduce the yield ratio of steel, it seems necessary to generate retained austenite and to control the recovery of dislocations of martensite and retained austenite during the tempering process. Therefore, the tempering treatment temperature is set to the Ac 1 point temperature or higher, a part of the metal structure is austenitized, and the mixed structure of the tempered martensite and the tempered bainite is formed by leaving it as it is during cooling or converting it to martensite again. It is considered that a steel sheet having a low yield ratio can be produced by forming the steel sheet.
【０００７】しかしながら、従来法のごとき焼き戻し方
法でこれを行えば、オーステナイト化部分が粗大とな
り、冷却後は粗大炭化物や粗大なマルテンサイトを含む
金属組織となるので強度、靱性の観点から好ましくな
い。また、オーステナイト化しなかった部分についても
焼き戻し温度が高いためにマルテンサイトの転位が著し
く減少したり、場合によっては再結晶により粗大なフェ
ライトが生成し、強度、靱性が著しく低下する。そこ
で、本発明者らは種々の熱処理条件を検討し、焼き戻し
温度をＡｃ1 点温度以上としながらも急速加熱、短時間
保持により強度、靱性を向上した上で鋼の降伏比を容易
に低下することを見いだした。However, if this is carried out by a tempering method such as the conventional method, the austenitized portion becomes coarse, and after cooling, it becomes a metal structure containing coarse carbides and coarse martensite, which is not preferable from the viewpoint of strength and toughness. .. In addition, since the tempering temperature is high even in the portion which has not been austenitized, martensite dislocations are remarkably reduced, and in some cases, coarse ferrite is generated by recrystallization, and strength and toughness are remarkably lowered. Therefore, the present inventors examined various heat treatment conditions, and improved the strength and toughness by rapidly heating and holding for a short time while keeping the tempering temperature at the Ac 1 point temperature or higher, and easily lower the yield ratio of steel. I found what to do.
【０００８】本発明法による効果は、Ａｃ1 点温度以上
での焼き戻しによって生じたオーステナイト部分をマル
テンサイトラス境界上などに微細に現出し（Ａｃ1 点温
度以下でマルテンサイトラス境界上などに析出したセメ
ンタイトがオーステナイトの核となる）、それに引き続
く冷却中にこれがマルテンサイト、残留オーステナイ
ト、セメンタイトあるいはこれらの混合物となること、
およびこのようにして生じたマルテンサイト、残留オー
ステナイト部分が転位の豊富さなどの為に降伏点の低下
と引っ張り強度の上昇に寄与するために生じると考えら
れる。一方、オーステナイト化しなかった部分について
も、急速加熱、短時間焼き戻しによって、金属組織中に
存在する炭化物は微細に分散し、マルテンサイト変態な
どの変態により導入された転位や加工されたオーステナ
イトから引き継がれた転位が金属組織中に多く残存する
事によって強度が上昇し、場合によっては可動転位が延
性を促進することによって鋼の靱性を増すのである。The effect of the method of the present invention is that the austenite portion produced by tempering at a temperature above the Ac 1 point is finely exposed on the martensite lath boundary or the like (precipitated on the martensite lath boundary or the like below the Ac 1 point temperature). Cementite is the core of austenite), which during subsequent cooling this becomes martensite, retained austenite, cementite or a mixture thereof,
It is considered that the martensite and the retained austenite portion thus generated contribute to the lowering of the yield point and the increase of the tensile strength due to the abundance of dislocations. On the other hand, even for the portion not transformed into austenite, the carbides present in the metal structure are finely dispersed by the rapid heating and the short tempering, and the dislocations introduced by the transformation such as martensite transformation or the processed austenite are taken over. The large amount of dislocations remaining in the metal structure increases the strength, and in some cases, the mobile dislocations promote ductility, thereby increasing the toughness of the steel.
【０００９】さらに、降伏点の低下に付いてはオーステ
ナイト化した際にオーステナイト部分がマルテンサイト
（フェライト）との固溶度の差に基づいて、残部金属組
織の固溶元素を吸収、低減するという効果も期待でき、
このような効果は一度オーステナイト化した部分がフェ
ライトとセメンタイトとなった場合でも有効である。以
上のような考え方によって、本発明法によれば、マルテ
ンサイトあるいはベイナイトの微細な金属組織状態を損
なうこと無く、その組織中の極めて微少な部分を一度オ
ーステナイト化し、この部分を冷却中に再び微細なマル
テンサイト、残留オーステナイト、セメンタイトもしく
はこの混合物として、焼き戻しマルテンサイトあるいは
ベイナイト中に分散させることにより、強度、靱性にす
ぐれた低降伏比高張力鋼板を製造し得るのである。Further, regarding the lowering of the yield point, when austenitized, the austenite portion absorbs and reduces solid solution elements of the balance metal structure based on the difference in solid solubility between martensite (ferrite). You can expect an effect,
Such an effect is effective even when the austenitized portion becomes ferrite and cementite. According to the method of the present invention based on the above-described concept, an extremely minute portion of the structure is once austenitized without impairing the fine metallographic state of martensite or bainite, and this portion is refined again during cooling. It is possible to produce a high-strength steel sheet with a low yield ratio and excellent strength and toughness by dispersing the above-mentioned martensite, retained austenite, cementite or a mixture thereof in tempered martensite or bainite.
【００１０】次に、生産性の見地からは図１に示すよう
に昇温速度を増加させ、保持を１５分以内の短時間とす
ることにより、焼き戻しに要する実処理時間を大幅に減
少させることができ、生産性を著しく向上することが可
能となるのである。即ち、本発明法を適用する事によっ
て、従来法に比してきわめて短時間で、強度、靱性に優
れた低降伏比鋼板の製造が可能なのである。このような
新しい発見に基づき本発明法における鋼の化学成分、製
造条件を詳細に調査した結果本発明者らは特許請求の範
囲の第１項、第２項に示したような強靱な厚鋼板の製造
方法を創案した。From the viewpoint of productivity, the rate of temperature increase is increased as shown in FIG. 1 and the holding time is kept within a short time of 15 minutes, whereby the actual processing time required for tempering is greatly reduced. Therefore, the productivity can be remarkably improved. That is, by applying the method of the present invention, it is possible to manufacture a low yield ratio steel sheet having excellent strength and toughness in an extremely short time compared with the conventional method. As a result of detailed investigation of the chemical composition and manufacturing conditions of the steel in the method of the present invention based on such a new discovery, the present inventors have found that the thick steel plate having the toughness as described in the first and second claims of the present invention. The manufacturing method of
【００１１】以下に製造方法の限定の理由について述べ
る。Ｃは鋼の強化を行うのに有効な元素であり０．０２
％未満では十分な強度が得られない。一方、その含有量
が０．５％を越えると、溶接性を劣化させる。Ｓｉは脱
酸元素として、また、鋼の強化元素として有効である
が、０．０１％未満の含有量ではその効果がない。一
方、１．０％を越えると、鋼の表面性状を損なう。Ｍｎ
は鋼の強化に有効な元素であり、０．０２％未満では十
分な効果が得られない。一方、その含有量が１０．０％
を越えると鋼の加工性を劣化させる。Ａｌは脱酸元素と
して添加されるが、０．１０％を越えると、鋼の表面性
状を劣化させる。The reason why the manufacturing method is limited will be described below. C is an effective element for strengthening steel and is 0.02
If it is less than%, sufficient strength cannot be obtained. On the other hand, if its content exceeds 0.5%, the weldability is deteriorated. Si is effective as a deoxidizing element and as a strengthening element for steel, but if the content is less than 0.01%, it is not effective. On the other hand, if it exceeds 1.0%, the surface properties of steel are impaired. Mn
Is an element effective for strengthening steel, and if it is less than 0.02%, a sufficient effect cannot be obtained. On the other hand, its content is 10.0%
If it exceeds the range, the workability of steel deteriorates. Al is added as a deoxidizing element, but if it exceeds 0.10%, it deteriorates the surface properties of steel.
【００１２】ＴｉおよびＮｂはいずれも微量の添加で結
晶粒の微細化と析出強化の面で有効に機能するので溶接
部の靱性を劣化させない範囲で使用しても良い。このよ
うな観点からその添加量の上限を０．１％とする。Ｃ
ｕ，Ｎｉ，Ｃｒ，Ｍｏ，Ｃｏ，Ｗはいずれも鋼の焼き入
れ性を向上させる元素であり、本発明の場合、その添加
により鋼の強度を高めることが出来る。しかし、過度の
添加は鋼の靱性および溶接性を損なうため、Ｃｕ≦１
０．０％、Ｎｉ≦１０．０％、Ｃｒ≦３．０％、Ｍｏ≦
３．０％、Ｃｏ≦１０．０％、Ｗ≦３．０％に限定す
る。Ｖは析出強化により鋼の強度を高めるのに有効であ
るが、過度の添加は鋼の靱性を損なうために、その上限
を０．１０％とする。Ｂは鋼の焼き入れ性を向上させる
元素である。本発明における場合、その添加により鋼の
強度を高めることができるが、過度の添加はＢの析出物
を増加させ鋼の靱性を損ねるのでその含有量の上限を
０．００３％とする。Both Ti and Nb effectively function in terms of grain refinement and precipitation strengthening when added in a small amount, so they may be used in a range that does not deteriorate the toughness of the welded portion. From this point of view, the upper limit of the added amount is 0.1%. C
u, Ni, Cr, Mo, Co and W are all elements that improve the hardenability of the steel, and in the case of the present invention, the addition of them can enhance the strength of the steel. However, excessive addition impairs the toughness and weldability of steel, so Cu ≦ 1
0.0%, Ni ≦ 10.0%, Cr ≦ 3.0%, Mo ≦
It is limited to 3.0%, Co ≦ 10.0% and W ≦ 3.0%. V is effective in increasing the strength of the steel by precipitation strengthening, but excessive addition impairs the toughness of the steel, so its upper limit is made 0.10%. B is an element that improves the hardenability of steel. In the case of the present invention, the strength of the steel can be increased by its addition, but excessive addition increases the precipitates of B and impairs the toughness of the steel, so the upper limit of the content is made 0.003%.
【００１３】次に、本発明における製造条件に付いて述
べる。本発明はいかなる鋳造条件で鋳造された鋼片につ
いても有効であるので、特に鋳造条件を特定する必要は
ない。また、鋳片を冷却すること無くそのまま熱間圧延
を開始しても一度冷却した鋳片をＡｃ3 点以上に再加熱
した後に圧延を開始しても良い。なお、本発明において
は圧延あるいは圧延後の冷却の条件に付いては特に規定
するものではないが、それはいかなる圧延、冷却を行っ
ても本発明の有効性が失われないからである。ただし、
本発明では焼き戻しにより鋼中の結晶粒、炭化物を微細
に分散させるという目的があるので本発明の効果を最大
限に利用するためには、焼き入れ後に金属組織がマルテ
ンサイトあるいはベイナイトで、結晶粒が微細であるこ
とが望ましい。Next, the manufacturing conditions in the present invention will be described. Since the present invention is effective for a steel piece cast under any casting condition, it is not necessary to specify the casting condition. Alternatively, even if hot rolling is started as it is without cooling the slab, the slab that has been once cooled may be reheated to Ac 3 point or more and then rolled. In the present invention, the conditions of rolling or cooling after rolling are not particularly specified, but the effectiveness of the present invention is not lost even if any rolling or cooling is performed. However,
In the present invention, crystal grains in the steel by tempering, the purpose is to finely disperse the carbides, so in order to maximize the effect of the present invention, the metal structure after quenching is martensite or bainite, the crystal It is desirable that the grains are fine.
【００１４】次に、焼き戻し条件についてであるが、焼
き戻し温度をＡｃ1 点以上としたのはこれ未満では炭化
物をオーステナイト化することができないからである。
焼き戻し中の昇温速度を１℃／秒以上、Ａｃ1 点以上の
温度域での保持を１５分以内としたのは、昇温速度が遅
く、保持時間が長ければ昇温中に転位の回復、組織・析
出物の粗大化、固溶炭素原子の析出が生じてしまい強
度、靱性を高めることができないこととオーステナイト
の粗大化が進み、冷却後の組織が粗大で不均一となり、
靱性を劣化させるからである。Next, regarding the tempering conditions, the reason for setting the tempering temperature to the Ac 1 point or higher is that the carbide cannot be austenitized below this point.
The reason why the temperature rising rate during tempering is 1 ° C./sec or more and the holding time in the temperature range of Ac 1 point or more is 15 minutes or less is that the temperature rising rate is slow, and if the holding time is long, the dislocation Recovery, coarsening of the structure / precipitate, precipitation of solid solution carbon atoms cannot increase strength and toughness, and coarsening of austenite progresses, the structure after cooling becomes coarse and uneven,
This is because the toughness is deteriorated.
【００１５】[0015]
【実施例】次に本発明の実施例によって本発明の有効性
を示す。表１及び表２は実施例の鋼の成分を示すもので
ある。このような成分の鋼を表２及び表３に示す製造条
件で製造した場合に、同じく表２及び表３に示すような
強度、靱性、焼き戻しに要した処理時間が得られた。表
３、表４では本発明の条件に合致しない項目に下線をつ
けて示して有る。これによれば、本発明法は比較法に比
べ明らかに生産性が高く、引っ張り強度・靱性に優れた
低降伏比鋼板を製造することが可能であり、本発明は有
効である。EXAMPLES The effectiveness of the present invention will be shown by the examples of the present invention. Tables 1 and 2 show the components of the steels of the examples. When steels having such components were manufactured under the manufacturing conditions shown in Tables 2 and 3, strength, toughness, and treatment time required for tempering were also obtained as shown in Tables 2 and 3. In Tables 3 and 4, the items that do not meet the conditions of the present invention are underlined. According to this, the method of the present invention is obviously higher in productivity than the comparative method, and it is possible to manufacture a low yield ratio steel sheet excellent in tensile strength and toughness, and the present invention is effective.
【００１６】[0016]
【表１】 [Table 1]
【００１７】[0017]
【表２】 [Table 2]
【００１８】[0018]
【表３】 [Table 3]
【００１９】[0019]
【表４】 [Table 4]
【００２０】[0020]
【発明の効果】以上述べたように、本発明の実施によっ
て、従来法に比較して極めて短時間で、かつ強度、靱性
に優れた低降伏比鋼板が製造可能となり、生産性を著し
く向上することが出来た。As described above, by carrying out the present invention, a low yield ratio steel sheet excellent in strength and toughness can be manufactured in an extremely short time as compared with the conventional method, and the productivity is remarkably improved. I was able to do it.
【図１】本発明中の焼き戻し処理の説明図である。FIG. 1 is an explanatory diagram of a tempering process in the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 尾上 泰光 千葉県富津市新富20−１ 新日本製鐵株式 会社技術開発本部内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasumitsu Onoue 20-1 Shintomi, Futtsu City, Chiba Nippon Steel Corporation Corporate Technology Development Division
Claims (2)
板を直接焼き入れあるいは再加熱後に焼き入れし、その
後、焼き戻しを行って高張力鋼板を製造する方法におい
て、焼き入れ後の金属組織が主にベイナイト、マルテン
サイトあるいはこの混合組織であって、焼き戻し時の昇
温速度を１℃／秒以上、焼き戻し温度をＡｃ1 点以上の
温度とし、さらに保持を１５分以内で終了し、その後、
放冷もしくは強制冷却を行うことを特徴とする生産性の
高い高強度、高靱性低降伏比高張力鋼板の製造方法。1. By weight%, C: 0.02 to 0.5%, Mn: 0.02 to 10.0%, Si: 0.01 to 1.0%, Al: 0.1% or less, In a method for producing a high-strength steel sheet by directly quenching or quenching after quenching or reheating a steel sheet containing Fe, and the balance consisting of Fe and unavoidable impurities, the metal structure after quenching is mainly A bainite, martensite or a mixed structure thereof, the temperature rising rate during tempering is 1 ° C./sec or more, the tempering temperature is Ac 1 point or more, and the holding is completed within 15 minutes, ,
A method for producing a high-productivity, high-strength, high-toughness, low-yield-ratio, high-strength steel sheet characterized by performing cooling or forced cooling.
がＦｅおよび不可避的不純物からなる鋼板を直接焼き入
れあるいは再加熱後に焼き入れし、その後焼き戻しを行
って高張力鋼板を製造する方法において、焼き入れ後の
組織が主にマルテンサイト、ベイナイトあるいはこの混
合組織であって、焼き戻し時の昇温速度を１℃／秒以
上、焼き戻し温度をＡｃ1 点以上の温度とし、さらに保
持時間を１５分以内で終了し、その後放冷もしくは強制
冷却を行うことを特徴とする生産性の高い高強度、高靱
性低降伏比高張力鋼板の製造方法。2. By weight%, C: 0.02 to 0.5%, Mn: 0.02 to 10.0%, Si: 0.01 to 1.0%, Al: 0.1% or less, Is a basic component, Mo: 3.0% or less, Ni: 10.0% or less, Cr: 3.0% or less, V: 0.1% or less, Nb: 0.1% or less, Ti: 0. 1% or less, B: 0.003% or less, Cu: 10.0% or less, Co: 10.0% or less, W: 3.0% or less, or a balance containing at least two more. In the method for producing a high-strength steel sheet by directly quenching or reheating a steel sheet consisting of Fe and unavoidable impurities, and then tempering it, the structure after quenching is mainly martensite, bainite or this It has a mixed structure and is heated at a temperature rising rate of 1 ° C / sec or more during tempering. A high-productivity high-strength, high-toughness low-yield-ratio high-strength steel sheet characterized in that the return temperature is set to a temperature of Ac 1 point or higher, the holding time is finished within 15 minutes, and then cooling or forced cooling is performed. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02503092A JP3228986B2 (en) | 1992-02-12 | 1992-02-12 | Manufacturing method of high strength steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02503092A JP3228986B2 (en) | 1992-02-12 | 1992-02-12 | Manufacturing method of high strength steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05222450A true JPH05222450A (en) | 1993-08-31 |
| JP3228986B2 JP3228986B2 (en) | 2001-11-12 |
Family
ID=12154518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02503092A Expired - Lifetime JP3228986B2 (en) | 1992-02-12 | 1992-02-12 | Manufacturing method of high strength steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3228986B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0770696A4 (en) * | 1995-04-12 | 1997-07-16 | Mitsubishi Heavy Ind Ltd | High-strength and high-toughness heat-resisting steel |
| JPH11269606A (en) * | 1998-03-19 | 1999-10-05 | Kobe Steel Ltd | High strength hot rolled steel plate excellent in impact resistance and its production |
| US7662245B2 (en) * | 2003-05-27 | 2010-02-16 | Koyo Seiko Co., Ltd. | Steering rack comprising steel bar with rack teeth |
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| JP2018512508A (en) * | 2015-03-20 | 2018-05-17 | 宝山鋼鉄股▲分▼有限公司 | Low yield ratio high toughness thick steel plate excellent in low temperature impact toughness and method for producing the same |
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1992
- 1992-02-12 JP JP02503092A patent/JP3228986B2/en not_active Expired - Lifetime
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0770696A4 (en) * | 1995-04-12 | 1997-07-16 | Mitsubishi Heavy Ind Ltd | High-strength and high-toughness heat-resisting steel |
| US5817192A (en) * | 1995-04-12 | 1998-10-06 | Mitsubishi Jukogyo Kabushiki Kaisha | High-strength and high-toughness heat-resisting steel |
| JPH11269606A (en) * | 1998-03-19 | 1999-10-05 | Kobe Steel Ltd | High strength hot rolled steel plate excellent in impact resistance and its production |
| US7662245B2 (en) * | 2003-05-27 | 2010-02-16 | Koyo Seiko Co., Ltd. | Steering rack comprising steel bar with rack teeth |
| KR101376683B1 (en) * | 2011-09-15 | 2014-03-26 | 국방과학연구소 | High~strength high~tensile steel and manufacturing method thereof |
| JP2018512508A (en) * | 2015-03-20 | 2018-05-17 | 宝山鋼鉄股▲分▼有限公司 | Low yield ratio high toughness thick steel plate excellent in low temperature impact toughness and method for producing the same |
| US11180836B2 (en) | 2015-03-20 | 2021-11-23 | Baoshan Iron & Steel Co., Ltd. | Low-yield-ratio high-strength-toughness thick steel plate with excellent low-temperature impact toughness and manufacturing method therefor |
| WO2018117496A1 (en) * | 2016-12-20 | 2018-06-28 | 주식회사 포스코 | Steel for pressure vessels with excellent resistance to high-temperature tempering heat treatment and post-weld heat treatment and manufacturing method therefor |
| CN110088338A (en) * | 2016-12-20 | 2019-08-02 | 株式会社Posco | There is the steels for pressure vessel use and its manufacturing method of excellent drag to high tempering heat treatment and post weld heat treatment |
| CN110088338B (en) * | 2016-12-20 | 2021-10-29 | 株式会社Posco | Steel for pressure vessel having excellent resistance to high-temperature tempering heat treatment and post-weld heat treatment, and method for manufacturing same |
| JP2022516182A (en) * | 2019-01-07 | 2022-02-24 | 南京鋼鉄股▲ふん▼有限公司 | 690MPa grade extra-thick steel sheet and its manufacturing method |
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|---|---|
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