JPH03223420A - Production of high strength steel - Google Patents
Production of high strength steelInfo
- Publication number
- JPH03223420A JPH03223420A JP1575390A JP1575390A JPH03223420A JP H03223420 A JPH03223420 A JP H03223420A JP 1575390 A JP1575390 A JP 1575390A JP 1575390 A JP1575390 A JP 1575390A JP H03223420 A JPH03223420 A JP H03223420A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- cooling
- point
- rolling
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 45
- 239000010959 steel Substances 0.000 title claims abstract description 45
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 238000005096 rolling process Methods 0.000 claims abstract description 25
- 238000001816 cooling Methods 0.000 claims abstract description 23
- 238000005496 tempering Methods 0.000 claims abstract description 14
- 238000005266 casting Methods 0.000 claims abstract description 7
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 6
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 6
- 238000005098 hot rolling Methods 0.000 claims abstract description 5
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 5
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 5
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 4
- 229910052802 copper Inorganic materials 0.000 claims abstract description 4
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 4
- 229910052742 iron Inorganic materials 0.000 claims abstract description 3
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 3
- 229910052782 aluminium Inorganic materials 0.000 claims abstract 3
- 229910052720 vanadium Inorganic materials 0.000 claims abstract 2
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 10
- 229910052799 carbon Inorganic materials 0.000 abstract description 7
- 239000000203 mixture Substances 0.000 abstract description 3
- 238000010791 quenching Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 9
- 230000000171 quenching effect Effects 0.000 description 9
- 230000009466 transformation Effects 0.000 description 9
- 229910001566 austenite Inorganic materials 0.000 description 6
- 229910000734 martensite Inorganic materials 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000004881 precipitation hardening Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000012733 comparative method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は強靭な厚鋼板の製造法に関するものである。[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing strong thick steel plates.
（従来の技術および発明が解決しようとする諜Ｎ）鋼構
造物の大型化に伴い、より強靭な鋼の開発が求められて
いる。通常引張強度６０ｋｇｆ／−以上の綱は焼入れに
よりマルテンサイトまたは下部ベイナイト変態を生じせ
しめその後の焼戻し処理により過飽和固溶炭素を炭化物
として析出せしめる方法で製造されている。このような
製造法は製造に要する時間も長くかつ製造費用も多大で
ある。(Intelligence to be Solved by the Prior Art and the Invention) As steel structures become larger, there is a need to develop stronger steel. Usually, steel having a tensile strength of 60 kgf/- or more is manufactured by a method in which martensite or lower bainite transformation is caused by quenching, and supersaturated solid solution carbon is precipitated as carbide by a subsequent tempering treatment. Such a manufacturing method takes a long time and costs a lot of money.
近年、このような通常の焼入れ焼戻し処理の欠点を補う
べく圧延後そのまま焼入れを行う直接焼入れ技術が開発
された。この方法は製造費用の低減と鋼の強靭化の面で
ある程度の効果を生んでいる。このような製造法として
は例えば特公昭５３６６１６号公報、特公昭５５−４９
１３１号公報、特公昭５８−３０１１号公報等に記載の
方法がある。しかしこのような技術では、焼戻し工程が
従来のままであるためにその低生産性に起因して基本的
には製造コストが高い。また冶金面から見て最適な金属
組織の状態を得られているとは言いがたく、さらに強靭
な鋼の製造方法が強く求められてきた。In recent years, a direct quenching technique has been developed in which quenching is performed directly after rolling in order to compensate for the drawbacks of conventional quenching and tempering treatments. This method has produced some effects in terms of reducing manufacturing costs and increasing the toughness of steel. Examples of such a manufacturing method include Japanese Patent Publication No. 536616 and Japanese Patent Publication No. 55-49.
There are methods described in Japanese Patent Publication No. 131, Japanese Patent Publication No. 58-3011, etc. However, in such a technique, the manufacturing cost is basically high due to the low productivity since the tempering process remains conventional. Furthermore, from a metallurgical point of view, it cannot be said that an optimal metal structure has been obtained, and there has been a strong demand for a method for producing even stronger steel.
本発明の目的はこのような強靭鋼の製造方法を提供しよ
うとするものである。An object of the present invention is to provide a method for manufacturing such strong steel.
（課題を解決するための手段）
本発明は上記のような従来法の欠点を有利に排除しうる
、強靭鋼の製造法であり、その要旨とするところは次の
通りである。(Means for Solving the Problems) The present invention is a method for producing strong steel that can advantageously eliminate the drawbacks of the conventional methods as described above, and its gist is as follows.
（１ン１ｉ１ ％で
Ｃ： ０．０２〜０．２５％
Ｓｉ：０．０５〜０．６％
Ｍｎ： ０．３０〜３．５％
７１Ｊ ： ０．００５ 〜０．１０％残部がＦｅおよ
び不可避的不純物からなる鋼を、鋳造後、Ａｒ、点板下
の温度まで冷却することなくそのままあるいはＡｃ３点
以上の温度域に加熱後、９００℃以下Ａｒｓ点以上の温
度域で全圧下率の２０％以上の熱間圧延を加え、圧延終
了後２０秒以内に冷却を開始し５℃／秒以上６０℃／秒
以下の冷却速度で４５０℃以下まで冷却した後、４５０
℃以上Ａｃ、点板下の温度域まで１℃／秒以上の昇温速
度で焼戻すことを特徴とする強靭鋼の製造法。(C: 0.02-0.25% Si: 0.05-0.6% Mn: 0.30-3.5% 71J: 0.005-0.10% The balance is Fe and After casting, steel consisting of unavoidable impurities is heated as it is without cooling to the temperature below the Ar point plate, or after being heated to a temperature range of 3 Ac points or higher, and is heated to a temperature range of 900°C or higher than the Ars point by 20% of the total rolling reduction. % or more, start cooling within 20 seconds after the end of rolling, and cool to 450°C or less at a cooling rate of 5°C/second or more and 60°C/second or less, and then
A method for producing strong steel, characterized by tempering at a temperature increase rate of 1° C./sec or more to a temperature range of 1° C. or more to Ac or below the dot plate.
（２）重量％で
Ｃ： ０．０２〜０．２５％
Ｓｉ：０．０５〜０．６％
Ｍｎ：０．３０〜３．５％
７Ｖ： ｏ、ｏｏｓ〜０．１０％
さらに、
Ｔｉ≦０．１０％
Ｎｂ≦０．１０％
Ｃｕ≦３．０％
ＮｉＳｉ２．０％
Ｃｒ５１０６０％
Ｍｏ≦０．５％
ＣＯ≦１０．０％
Ｗ≦２．０％
■≦０．１０％
Ｂ≦０．００２５％
の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、鋳造後、Ａｒ３点以下の温度
まで冷却することなくそのままあるいは胱１点以上の温
度域に加熱後、９００℃以下Ａｒｓ点以上の温度域で全
圧下率の２０％以上の熱間圧延を加え、圧延終了後２０
秒以内に冷却を開始し５℃／秒以上６０℃／秒以下の冷
却速度で４５０℃以下まで冷却した後、４５０℃以上Ａ
ｃ、点板下の温度域まで１℃／秒以上の昇温速度で焼戻
すことを特徴とする強靭鋼の製造法。(2) In weight%, C: 0.02-0.25% Si: 0.05-0.6% Mn: 0.30-3.5% 7V: o, oos ~ 0.10% Furthermore, Ti≦ 0.10% Nb≦0.10% Cu≦3.0% NiSi2.0% Cr51060% Mo≦0.5% CO≦10.0% W≦2.0% ■≦0.10% B≦0. After casting, steel containing one or more of 0025% and the remainder consisting of Fe and unavoidable impurities may be cast as it is without cooling to a temperature below Ar 3 or after heating to a temperature range above Ar 1. , hot rolling is applied at a temperature range of 900°C or higher than the Ars point at a rate of 20% or more of the total rolling reduction, and after the completion of rolling 20%
Start cooling within seconds and cool to 450℃ or less at a cooling rate of 5℃/second or more and 60℃/second or less, then 450℃ or more A
c. A method for producing strong steel, characterized by tempering at a temperature increase rate of 1° C./sec or more to a temperature range below the dot plate.
以下本発明について詳細に説明する。The present invention will be explained in detail below.
本発明の根幹をなす技術思想は以下のとおりである。The technical idea underlying the present invention is as follows.
引張強度６０ｋｇｆ／−以上の鋼は焼入れ焼戻しまたは
圧延後の直接焼入れと焼戻しにより製造される場合が多
い、その強度・靭性のバランスは金属組織がマルテンサ
イトと下部へイナイトの混合組織となる場合に最良とな
ることが知られている。Steel with a tensile strength of 60 kgf/- or more is often manufactured by quenching and tempering or by direct quenching and tempering after rolling.The balance between strength and toughness is achieved when the metal structure is a mixed structure of martensite and lower heinite. known to be the best.
さらに焼入れ前のオーステナイトを加工された状態にお
くこと番こより、その混合組織の破面単位をより微細化
し良好な強度・靭性のバランスを得ることができること
が知られている。この加工の効果はオーステナイト中に
加工による欠陥を数多く存在せしめマルテンサイト変態
のようなシアーによる変態時のラスの大きさを微細化す
る効果および加ニオーステナイト中の転位が変態後の組
織中に引継がれるため延性が増す効果による。しかるに
これらの欠陥および転位は圧延後の時間とともに消滅し
てしまうため、圧延後できる限り早い時期に焼入れるこ
とが好ましい。さらに、変態後の組織中に引継がれた転
位は焼入れ後の通常の焼戻し条件では消失してしまうが
、焼戻し温度にいたるまでの昇温速度を速くすることに
より、転位を多量に残存させなから固溶炭素を炭化物と
じて析出せしめ得ることがわかった。すなわち圧延直後
の焼入れと焼戻し時の昇温速度の増加の組み合わせによ
り従来得ることができなかったような良好な強度・靭性
バランスを有する高張力鋼を製造することが可能となっ
た。Furthermore, it is known that by leaving the austenite in a processed state before quenching, it is possible to further refine the fracture surface units of the mixed structure and obtain a good balance between strength and toughness. The effects of this processing include the presence of many processing defects in austenite, the effect of refining the size of laths during shear transformation such as martensitic transformation, and the effect of dislocations in diaustenite being inherited in the structure after transformation. This is due to the effect of increasing ductility. However, since these defects and dislocations disappear with time after rolling, it is preferable to quench the steel as soon as possible after rolling. Furthermore, dislocations inherited in the structure after transformation disappear under normal tempering conditions after quenching, but by increasing the rate of temperature rise up to the tempering temperature, a large amount of dislocations can be prevented from remaining. It has been found that solute carbon can be precipitated as carbide. In other words, by combining quenching immediately after rolling and increasing the temperature increase rate during tempering, it has become possible to produce high-strength steel with a good balance of strength and toughness that was previously impossible to obtain.
このような新しい発見に基づき、綱の化学成分、鋼の製
造条件を詳細に調査した結果、本発明者らは特許請求の
範囲第１項から第２項に示したような強靭鋼の製造法を
創案した。以下に製造方法の限定理由を詳細に説明する
。まず本発明における出発材の成分の限定理由について
述べる。Based on these new discoveries, as a result of detailed investigation into the chemical composition of steel and manufacturing conditions for steel, the present inventors have developed a method for manufacturing strong steel as set forth in claims 1 and 2. was invented. The reasons for limiting the manufacturing method will be explained in detail below. First, the reasons for limiting the components of the starting materials in the present invention will be described.
Ｃは鋼を強化する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
．２５％を越えると、溶接性を劣化させる。C is an effective element for strengthening steel, and if it is less than 0.02%, sufficient strength cannot be obtained. On the other hand, its content is 0
．． When it exceeds 25%, weldability deteriorates.
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、０．０５％未満の含有量ではその効果はない。Although Si is effective as a deoxidizing element and as a strengthening element for steel, it has no effect if the content is less than 0.05%.
一方、０．６％を越えると、鋼の表面性状を損なう。On the other hand, if it exceeds 0.6%, the surface quality of the steel will be impaired.
Ｍｎは鋼の強化に有効な元素であり、０．３０％未満で
は十分な効果が得られない、一方、その含有量が３．５
％を越えると鋼の加工性を劣化させる。Mn is an effective element for strengthening steel, and if it is less than 0.30%, sufficient effect cannot be obtained; on the other hand, if its content is 3.5%,
%, the workability of steel deteriorates.
Ｍは脱酸元素として添加される。ｏ、ｏｏｓ％未溝の含
有量ではその効果がなく、０．１０％を越えると、鋼の
表面性状を損なう。M is added as a deoxidizing element. The content of o, oos% ungrooved has no effect, and when it exceeds 0.10%, the surface quality of the steel is impaired.
ＴｉおよびＮｂはいずれも微量の添加で結晶粒の微細化
と析出硬化の面で有効に機能するから溶接部の靭性を劣
化させない範囲で添加しても良い。この観点から、Ｎｂ
、 Ｔｉともその添加量の上限を０．１０％とする。Both Ti and Nb function effectively in terms of crystal grain refinement and precipitation hardening when added in small amounts, so they may be added within a range that does not deteriorate the toughness of the weld zone. From this point of view, Nb
The upper limit of the amount of addition of both Ti and Ti is 0.10%.
Ｃｕ、 Ｎｉ、 Ｃｒ、 Ｍｏ、 Ｃｏ、 Ｗはいずれ
も鋼の焼入れ性を向上させる元素である０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、過度の量の添加は鋼の溶接性を損なうため、Ｃｕ≦
３、０％、ＮｉＳｉ２．０％、Ｃｒ≦１０．０％、Ｍｏ
≦０．５％、Ｃｏ≦１０．０％、Ｗ≦０．０％に限定す
る。Cu, Ni, Cr, Mo, Co, and W are all elements that improve the hardenability of steel.In the case of the present invention, their addition can increase the strength of steel, but adding excessive amounts Cu≦
3.0%, NiSi2.0%, Cr≦10.0%, Mo
It is limited to ≦0.5%, Co≦10.0%, and W≦0.0%.
■は析出硬化により鋼の強度を高めるのに有効であるが
、過度の添加は鋼の靭性を損なうため、その上限を０．
１０％とする。(2) is effective in increasing the strength of steel through precipitation hardening, but excessive addition impairs the toughness of steel, so its upper limit should be set at 0.
10%.
Ｂは鋼の焼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て鋼の靭性を
損なうためその含有量の上限を０．００２５％とする。B is an element that improves the hardenability of steel. In the case of the present invention, the addition of B can increase the strength of the steel, but excessive addition increases B precipitates and impairs the toughness of the steel, so the upper limit of its content is set to 0.0025%.
次に本発明における製造条件について述べる。Next, the manufacturing conditions in the present invention will be described.
本発明はいかなる鋳造条件で鋳造された鋳片についても
有効であるので、特に鋳造条件を制限する必要はない。Since the present invention is effective for slabs cast under any casting conditions, there is no need to particularly limit the casting conditions.
また鋳片を冷やすことな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点以上の温度に再加熱した
後に圧延を開始しても良い０本発明においては、変態前
のオーステナイト中の転位密度を十分高めておく必要が
あるため、所定の圧延温度域において所定の圧下率以上
の圧延を施す必要がある。圧延温度９００℃Ｍではオー
ステナイトが再結晶してしまうため転位密度の量が著し
く減少してしまう。また圧延温度がＡｒ１点未満では変
態が開始してしまい強度が低下する。圧下率２０％未満
では転位密度が十分導入されない、圧延終了後は圧延に
より導入された金属組織的欠陥および転位が減少してし
まう前に焼入れる必要がある。その時間は圧延終了後２
０秒以内である。また加工を受けたオーステナイトを十
分マルテンサイトおよび下部へイナイトに変態させるた
めに５℃／秒以上の冷却速度で冷却する。In addition, hot rolling may be started without cooling the slab, or rolling may be started after the once cooled slab is reheated to a temperature of AC3 or higher.In the present invention, in the austenite before transformation, Since it is necessary to sufficiently increase the dislocation density of the steel, it is necessary to perform rolling at a predetermined reduction rate or higher in a predetermined rolling temperature range. At a rolling temperature of 900° C.M, austenite recrystallizes, resulting in a significant decrease in dislocation density. Furthermore, if the rolling temperature is less than 1 point Ar, transformation will start and the strength will decrease. If the rolling reduction is less than 20%, sufficient dislocation density will not be introduced, and after rolling, it is necessary to quench before the metallographic defects and dislocations introduced by rolling are reduced. The time is 2 after the end of rolling.
Within 0 seconds. Further, in order to sufficiently transform the processed austenite into martensite and lower heinite, the austenite is cooled at a cooling rate of 5° C./second or more.
また６０℃／秒超の冷却速度で冷却すると鋼が硬化しす
ぎて靭性を損なう。冷却終了温度を４５０℃以下までと
限定した理由はそれより高い温度では十分にマルテンサ
イトおよび下部ベイナイトに変態させることができない
ためである。焼戻し温度は４５０℃未満では固溶炭素が
十分に析出せずまたＡｃ、点超では変態が開始してしま
い強度が低下する。焼戻し中の昇温速度を１℃／秒以上
としたのは、それ未満の昇温速度では固溶炭素の析出に
先立って転位が消失してしまい靭性が劣化するためであ
る。Furthermore, if the steel is cooled at a cooling rate exceeding 60° C./second, the steel will harden too much and its toughness will be impaired. The reason why the cooling end temperature is limited to 450° C. or lower is that at higher temperatures, sufficient transformation into martensite and lower bainite cannot be achieved. If the tempering temperature is less than 450°C, solid solution carbon will not precipitate sufficiently, and if it exceeds the Ac point, transformation will begin and the strength will decrease. The reason why the temperature increase rate during tempering is set to 1° C./sec or more is because if the temperature increase rate is less than that, dislocations disappear before solid solution carbon precipitates, resulting in deterioration of toughness.
（実施例）
次に本発明を実施例にもとづいて詳細に説明する。まず
表１に示す成分の綱について表２に示す本発明方法およ
び比較方法を適用した場合、表２表に示すような強度・
靭性が得られ、明らかに本発明により強度・靭性バラン
スの向上かもたらされており、
本発明は有効である。(Example) Next, the present invention will be explained in detail based on an example. First, when the method of the present invention and the comparative method shown in Table 2 are applied to the classes of components shown in Table 1, the strength and
Toughness was obtained, and the present invention clearly brought about an improvement in the strength/toughness balance, so the present invention is effective.
（注１）再加熱圧延の場合の圧延前の加熱温度Ｍｏ、
１〜１０ １０００℃
Ｍｏ、１１．１２ ８３５℃
Ｎα１５〜２２ ８３０℃
Ｎα２３〜２９ １１５０℃
Ｎα３０〜３６ １０５０℃
Ｎα３７ １０００℃
Ｍｏ、３８，３９ １０５０℃
Ｍｏ、４０ １０００℃
Ｍｏ、４１ ４２ １１００℃
（注２ ） Ｍｏ、４０〜４２は圧延後３０℃まで０．
５℃／秒で空冷、その後Ｎ０４０は９００ ℃に、Ｎα
４１，４２は８３０℃に再加熱し焼入れ焼戻しを行った
。(Note 1) Heating temperature Mo before rolling in case of reheat rolling,
1-10 1000℃ Mo, 11.12 835℃ Nα15-22 830℃ Na23-29 1150℃ Nα30-36 1050℃ Nα37 1000℃ Mo, 38,39 1050℃ Mo, 40 1000℃ Mo, 41 42 1100℃ (Note 2) Mo, 40-42 has a temperature of 0.0% up to 30°C after rolling.
Air cooling at 5°C/s, then N040 to 900°C, Nα
Nos. 41 and 42 were reheated to 830°C and quenched and tempered.
（発明の効果）
本発明によれば、強度・靭性バランスの向上した強靭鋼
を安価に従供することができる。(Effects of the Invention) According to the present invention, strong steel with an improved balance of strength and toughness can be provided at low cost.
Claims (2)
、Ａｒ＿３点以下の温度まで冷却することなくそのまま
あるいはＡｃ＿３点以上の温度域に加熱後、９００℃以
下Ａｒ＿３点以上の温度域で全圧下率の２０％以上の熱
間圧延を加え、圧延終了後２０秒以内に冷却を開始し５
℃／秒以上６０℃／秒以下の冷却速度で４５０℃以下ま
で冷却した後、４５０℃以上Ａｃ＿１点以下の温度域ま
で１℃／秒以上の昇温速度で焼戻すことを特徴とする強
靭鋼の製造法。(1) C: 0.02-0.25% Si: 0.05-0.6% Mn: 0.30-3.5% N: 0.005-0.10% The balance is Fe and After casting, steel consisting of unavoidable impurities is cast as it is without cooling to a temperature below the Ar_3 point, or after being heated to a temperature range of the Ac_3 point or above, at a temperature below 900°C or above the Ar_3 point by 20% or more of the total reduction rate. Add hot rolling and start cooling within 20 seconds after the end of rolling.
A tough steel characterized by being cooled to 450°C or less at a cooling rate of 1°C/second or more and 60°C/second or less, and then tempered at a heating rate of 1°C/second or more to a temperature range of 450°C or more and Ac_1 point or less. manufacturing method.
避的不純物からなる鋼を、鋳造後、Ａｒ＿３点以下の温
度まで冷却することなくそのままあるいはＡｃ＿３点以
上の温度域に加熱後、９００℃以下Ａｒ＿３点以上の温
度域で全圧下率の２０％以上の熱間圧延を加え、圧延終
了後２０秒以内に冷却を開始し５℃／秒以上６０℃／秒
以下の冷却速度で４５０℃以下まで冷却した後、４５０
℃以上Ａｃ＿１点以下の温度域まで１℃／秒以上の昇温
速度で焼戻すことを特徴とする強靭鋼の製造法。(2) C: 0.02-0.25% Si: 0.05-0.6% Mn: 0.30-3.5% Al: 0.005-0.10% Furthermore, Ti≦ 0.10% Nb≦0.10% Cu≦3.0% Ni≦10.0% Cr≦10.0% Mo≦3.5% Co≦10.0% W≦2.0% V≦0. After casting, steel containing one or more of 10% B≦0.0025%, with the balance consisting of Fe and unavoidable impurities, is cast as it is without cooling to a temperature of Ar_3 or lower, or is heated to a temperature of Ac_3 or higher. After heating in the temperature range, hot rolling is applied at a temperature range of 900°C or lower and Ar_3 points or higher at a reduction rate of 20% or more of the total rolling reduction, and cooling is started within 20 seconds after the end of rolling, and cooling is started at 5°C/second or higher and 60°C/second After cooling to 450℃ or less at the following cooling rate,
A method for producing strong steel, characterized by tempering at a temperature increase rate of 1° C./sec or more to a temperature range of 1° C. to Ac_1 point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015753A JPH0774380B2 (en) | 1990-01-25 | 1990-01-25 | Manufacturing method of high strength steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015753A JPH0774380B2 (en) | 1990-01-25 | 1990-01-25 | Manufacturing method of high strength steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03223420A true JPH03223420A (en) | 1991-10-02 |
| JPH0774380B2 JPH0774380B2 (en) | 1995-08-09 |
Family
ID=11897537
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2015753A Expired - Lifetime JPH0774380B2 (en) | 1990-01-25 | 1990-01-25 | Manufacturing method of high strength steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0774380B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5505219A (en) * | 1994-11-23 | 1996-04-09 | Litton Systems, Inc. | Supercritical fluid recirculating system for a precision inertial instrument parts cleaner |
| JP4517459B2 (en) * | 2000-06-15 | 2010-08-04 | 住友金属工業株式会社 | Manufacturing method of steel material having ultrafine martensite structure |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4390576B2 (en) | 2003-03-04 | 2009-12-24 | 株式会社小松製作所 | Rolling member |
| JP4390526B2 (en) | 2003-03-11 | 2009-12-24 | 株式会社小松製作所 | Rolling member and manufacturing method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6156268A (en) * | 1984-08-24 | 1986-03-20 | Nippon Steel Corp | High toughness and high tensile steel and its manufacture |
| JPH01176027A (en) * | 1987-12-29 | 1989-07-12 | Nippon Steel Corp | Manufacture of steel plate for welding construction having low yield ratio and high tensile strength |
| JPH01176029A (en) * | 1987-12-28 | 1989-07-12 | Kobe Steel Ltd | Manufacture of high-tensile steel plate with low yield ratio by accelerated cooling method |
-
1990
- 1990-01-25 JP JP2015753A patent/JPH0774380B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6156268A (en) * | 1984-08-24 | 1986-03-20 | Nippon Steel Corp | High toughness and high tensile steel and its manufacture |
| JPH01176029A (en) * | 1987-12-28 | 1989-07-12 | Kobe Steel Ltd | Manufacture of high-tensile steel plate with low yield ratio by accelerated cooling method |
| JPH01176027A (en) * | 1987-12-29 | 1989-07-12 | Nippon Steel Corp | Manufacture of steel plate for welding construction having low yield ratio and high tensile strength |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5505219A (en) * | 1994-11-23 | 1996-04-09 | Litton Systems, Inc. | Supercritical fluid recirculating system for a precision inertial instrument parts cleaner |
| JP4517459B2 (en) * | 2000-06-15 | 2010-08-04 | 住友金属工業株式会社 | Manufacturing method of steel material having ultrafine martensite structure |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0774380B2 (en) | 1995-08-09 |
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