JPH0379716A - Manufacture of low yield ratio high tensile strength steel having good weldability - Google Patents
Manufacture of low yield ratio high tensile strength steel having good weldabilityInfo
- Publication number
- JPH0379716A JPH0379716A JP21506889A JP21506889A JPH0379716A JP H0379716 A JPH0379716 A JP H0379716A JP 21506889 A JP21506889 A JP 21506889A JP 21506889 A JP21506889 A JP 21506889A JP H0379716 A JPH0379716 A JP H0379716A
- Authority
- JP
- Japan
- Prior art keywords
- less
- yield ratio
- tensile strength
- steel
- low yield
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 31
- 239000010959 steel Substances 0.000 title claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000001816 cooling Methods 0.000 claims abstract description 19
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims abstract description 9
- 229910052802 copper Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 4
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 4
- 230000001105 regulatory effect Effects 0.000 claims abstract description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 3
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 3
- 229910052720 vanadium Inorganic materials 0.000 claims abstract 2
- 238000005496 tempering Methods 0.000 claims description 10
- 238000010791 quenching Methods 0.000 claims description 7
- 230000000171 quenching effect Effects 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 abstract description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 5
- 230000009466 transformation Effects 0.000 abstract description 5
- 229910052804 chromium Inorganic materials 0.000 abstract 1
- 229910001566 austenite Inorganic materials 0.000 description 13
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 238000005336 cracking Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910003336 CuNi Inorganic materials 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- ZPUCINDJVBIVPJ-LJISPDSOSA-N ***e Chemical compound O([C@H]1C[C@@H]2CC[C@@H](N2C)[C@H]1C(=O)OC)C(=O)C1=CC=CC=C1 ZPUCINDJVBIVPJ-LJISPDSOSA-N 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010583 slow cooling Methods 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〉
本発明は建築２ＭＡ梁、タンクなどの鉄鋼構造物に利用
される、溶接割れ感受性が低く、引張強さが６０ｋｇｆ
／−以上で降伏比が８０％以下の溶接性の良好な低降伏
比高張力鋼の製造方法に関するものである。[Detailed Description of the Invention] <Industrial Application Field> The present invention is applied to steel structures such as architectural 2MA beams and tanks, which have low weld crack susceptibility and a tensile strength of 60 kgf.
The present invention relates to a method for manufacturing a low yield ratio high tensile strength steel having good weldability and a yield ratio of 80% or less.
〈従来の技術〉
建築、橋梁、タンクなどの鉄鋼構造物の大型化に伴い、
それに使用される鋼材には高強度化が求められる一方で
、構造物の安全性、すなわち脆性破壊防止の奴点から降
伏比の低いこと、溶接性の良いことが求められている。<Conventional technology> As steel structures such as buildings, bridges, and tanks become larger,
While high strength is required for the steel materials used in these applications, they are also required to have a low yield ratio and good weldability in order to ensure the safety of the structure, that is, to prevent brittle fracture.
しかしながら、−ｆＱに高強度化とともに降伏比は上昇
し、溶接性は低下する（頃向にあり、引張強さが６０ｋ
ｇｆ／−以上の高張力鋼では８０％以下の低降伏比と良
好な溶１妾性を兼備させることは容易ではない。However, as the strength increases at -fQ, the yield ratio increases and weldability decreases (at around -fQ, the tensile strength is 60k).
It is not easy to achieve both a low yield ratio of 80% or less and good weldability in high tensile strength steels with gf/- or more.
従来の低降伏比高張力鋼の製造方法としては、例えば特
公昭５５−５００９０号公報に開示された方法があるが
、これは炭素当量が０．３５〜０．５０％の鋼を単にフ
ェライトとオーステナイトの２相域温度に再加熱してか
ら焼入れるもので、低降伏比化には有効であるが、炭素
当量が０．３５〜０．５０％と高いため溶接性があまり
良くない、炭素当量が高いと、例えば日本鋼管技報Ｎａ
１２２ （１９８８） Ｐ ９で示されるように、炭
素当１ （Ｃ，、、） ０．４５％からなる組成鋼では
引張強さで６０ｋｇｆ／ｓ４以上、降伏比で８０％以下
が得られるものの、溶接性はＹ割れ防止予熱温度で１０
０℃と高い、このように従来法では溶接性の良好な低降
伏比６０キロ鋼が得られなかった。As a conventional method for producing high tensile strength steel with a low yield ratio, for example, there is a method disclosed in Japanese Patent Publication No. 55-50090. It is reheated to the temperature in the two-phase region of austenite and then quenched, and is effective for lowering the yield ratio, but the weldability is not very good because the carbon equivalent is as high as 0.35 to 0.50%. If the equivalent is high, for example, Nippon Kokan Giho Na
122 (1988) P 9, a steel with a composition of 0.45% carbon per 1 (C,,,) can obtain a tensile strength of 60 kgf/s4 or more and a yield ratio of 80% or less, Weldability is 10 at preheating temperature to prevent Y cracking.
The temperature is as high as 0°C, and thus a low yield ratio 60kg steel with good weldability could not be obtained using the conventional method.
〈発明が解決しようとするｉ＊ｉ＞
本発明はこのような現状に鑑みてなされたもので、その
目的とするところは、Ｙ型割れ防止予熱温度で２５°Ｃ
以下の良好な溶接性を有し、かつ降伏比で８０％以下、
引張強さで６０ｋｇｆ／ｍＪ以上の溶接性の優れた低降
伏比高張力鋼及びその製造方法を提案することである。<i*i to be solved by the invention> The present invention was made in view of the current situation, and its purpose is to prevent Y-shaped cracking at a preheating temperature of 25°C.
It has the following good weldability, and the yield ratio is 80% or less,
The object of the present invention is to propose a low yield ratio high tensile strength steel with a tensile strength of 60 kgf/mJ or more and excellent weldability, and a method for manufacturing the same.
く課題を解決するための手段〉
本発明者らは、溶接性が良好で、かつ高張力で低降伏比
の得られる成分系および熱処理方法について研究を重ね
た結果、Ｃ，９，を殆ど高めない、即ち溶接性をあまり
低下させない元素であるＣｕ及びＮｉを主成分とし、フ
ェライトとオーステナイトの２相域に加熱保持した後、
焼入れ焼もどしすることにより、溶接性の優れた低降伏
比高張力鋼が製造できることを見出した。Means for Solving the Problems〉 As a result of repeated research into a component system and a heat treatment method that provide good weldability, high tensile strength, and a low yield ratio, the present inventors have found that C,9, has almost increased. In other words, the main components are Cu and Ni, which are elements that do not significantly reduce weldability, and after being heated and maintained in the two-phase region of ferrite and austenite,
It has been discovered that a low yield ratio, high tensile strength steel with excellent weldability can be produced by quenching and tempering.
即ち本発明は、重量％にて、Ｃ： ０．０３〜０．０８
％。That is, in the present invention, C: 0.03 to 0.08 in weight%
%.
Ｓｉ ： ０．０５〜１．２０％、 Ｍｎ ： ０．５
０〜１．６０％、 Ｃｕ ： ０．８０−２．５０％、
Ｎｉ ： ０．４０〜２．００％、 Ｐ ： ０
．０３０％以下Ｓ ： ０．０２０％以下、 Ｎ ：
０．００６０％以下を含有し、さらに必要に応じてＣｒ
： ０．５０％以下、 Ｍｏ ： ０．５０％以下、
Ｖ：０．０６％以下、 Ｎｂ！ ０．０４０％以下１
Ｂ＝０、００５０％以下、 Ｔｉ ： ０．０６０％
以下のｔ種以上を含み、かつ
４６
４０ ５
４ １４
が０．３５％以下に規制され、残部がＦｅ及び不可避的
不純物からなる鋼を、Ａｃ３〜Ａｃ＋変態点間の２相域
温度に加熱保持した後、空冷以上温度で焼入れし、その
ｉ！ｔＡｃ＋点以下の温度で焼もどしを行うことを特徴
とする引張り強さが６０ｋｇｆ／−以上、かつ降伏比が
８０％以下である溶接性の良好な低降伏比高張力鋼の製
造方法である。Si: 0.05-1.20%, Mn: 0.5
0-1.60%, Cu: 0.80-2.50%,
Ni: 0.40-2.00%, P: 0
．． 0.030% or less S: 0.020% or less, N:
Contains 0.0060% or less, and further contains Cr as necessary.
: 0.50% or less, Mo: 0.50% or less,
V: 0.06% or less, Nb! 0.040% or less1
B=0, 0.050% or less, Ti: 0.060%
A steel containing the following t types or more, with 46 40 5 4 14 regulated to 0.35% or less, and the remainder consisting of Fe and unavoidable impurities, is heated and held at a temperature in the two-phase region between Ac3 and Ac+ transformation points. After that, it is quenched at a temperature higher than air cooling, and the i! This is a method for producing a low yield ratio high tensile strength steel with good weldability, having a tensile strength of 60 kgf/- or more and a yield ratio of 80% or less, which is characterized by performing tempering at a temperature below the tAc+ point.
〈作 用〉 次に、まず成分組成の限定理由を述べる。<For production> Next, we will first discuss the reasons for limiting the component composition.
Ｃ： ０．０３〜０．０８％
Ｃは高強度を得るために０．０３％以上必要であるが、
０．０８％を超えると良好な溶接性が得られない。C: 0.03-0.08% C is required at least 0.03% to obtain high strength, but
If it exceeds 0.08%, good weldability cannot be obtained.
Ｓｔ ： ０．０５〜１．２０％
Ｓｉは０．０５％以上は脱酸剤とし°ζ必要であるが、
１．２０％を超えると溶接性、靭性を低下させる。St: 0.05-1.20% 0.05% or more of Si is required as a deoxidizing agent, but
If it exceeds 1.20%, weldability and toughness will deteriorate.
Ｍｎ ： ０．５０〜１．６０％
Ｍｎは焼入性の確保及び強度確保のため０．５０％以上
必要であるが、■、６０％超の過剰添加は溶接性を低下
させる。Mn: 0.50 to 1.60% Mn is required to be 0.50% or more to ensure hardenability and strength, but excessive addition of more than 60% reduces weldability.
Ｃｕ ： ０．８０〜２．５０％、 Ｎｉ ： ０．４
０〜２．００％Ｃｕ、 Ｎｉは固溶強化元素として溶接
性をほとんど低下させることなく強度向上に寄与する。Cu: 0.80-2.50%, Ni: 0.4
0 to 2.00% Cu and Ni contribute to improving strength as solid solution strengthening elements without substantially reducing weldability.
またＡｃ３〜＾Ｃ８変態点間の温度保持中に、オーステ
ナイト相中にＣと同様に濃化し焼入性向上に寄与する。Further, during temperature maintenance between the Ac3 and C8 transformation points, C is concentrated in the austenite phase in the same way as C and contributes to improving hardenability.
さらにオーステナイト中に濃化したＣｕは焼入れで過飽
和状態となり、その後の焼もどし時に析出して強化する
。この析出強化は主としてＣｕの濃化した硬化相で生じ
るため、フェライトをあまり硬化しない、そのため降伏
比を高めず、引張強さを向上させるに有効である。この
ような析出強化作ｍを得るためにはＣｕ０．８０％以上
が必要であるが、Ｃｕは熱間加工性を低下させる。 Ｃ
ｕの熱間加工性の低下を抑えるにはほぼ当量のＮｉ添加
が必要であり、経済性の観点からＣｕの上限を２．５０
％とした。Ｎｉは強度、靭性とも向上するが、０．４０
％以下ではその効果が小さい、しかし高価なＮｉの過剰
添加は経済的でないことからＮｔＧ、４０〜２．００％
に制限した。Further, Cu concentrated in austenite becomes supersaturated during quenching, and is precipitated and strengthened during subsequent tempering. Since this precipitation strengthening mainly occurs in the hardened phase enriched with Cu, it does not harden the ferrite much, so it is effective in improving the tensile strength without increasing the yield ratio. In order to obtain such precipitation strengthening, Cu of 0.80% or more is required, but Cu deteriorates hot workability. C
In order to suppress the deterioration of hot workability of u, it is necessary to add approximately equivalent amount of Ni, and from the economic point of view, the upper limit of Cu is set at 2.50.
%. Ni improves both strength and toughness, but 0.40
% or less, the effect is small; however, excessive addition of expensive Ni is not economical, so NtG, 40 to 2.00%
limited to.
Ｐ ７０．０３０％以下、 Ｓ ０．０２０％以下Ｐ、
Ｓともに溶接性、延靭性を低下さ・仕るので、それぞれ
０．０３０％以下、 ０．０２０％以下に限定した。P 70.030% or less, S 0.020% or less P,
Since both S decreases weldability and ductility, it is limited to 0.030% or less and 0.020% or less, respectively.
Ｎ ： ０．００６０％以下
Ｎは溶接性２靭性を低下させるので０．００６０％以下
に限定した。N: 0.0060% or less N reduces weldability and toughness, so it was limited to 0.0060% or less.
Ｃｒ ： ０．５（１％以下、Ｎｏ：０．５０％以下。Cr: 0.5 (1% or less, No: 0.50% or less.
Ｖ ： ０．０６０％以下
いずれの元素もオーステナイト中に固溶して焼入性を高
めるとともに、焼もどし時に析出し焼もどし軟化抵抗を
高め強度上昇に有効であるが、過剰の添加は炭化物の析
出強化により降伏比の上昇をきたすとともに、溶接性、
延靭性を低下するのでそれぞれの上限を上記のとおりと
した。V: 0.060% or less Both elements dissolve in solid solution in austenite to improve hardenability, and also precipitate during tempering, increasing temper softening resistance and are effective in increasing strength. Precipitation strengthening increases the yield ratio and improves weldability and
Since the ductility and toughness are reduced, the respective upper limits were set as above.
Ｎｂ：０．０４０％以下、 Ｔｔ ： ０．０６０％
以下いずれも一部オーステ・）・イト中に固溶し強度を
高め、また一部は析出し結晶粒度を微細化する。Nb: 0.040% or less, Tt: 0.060%
A portion of each of the following solid-solves in the austenite to increase its strength, and a portion precipitates to refine the grain size.
多量に添加すると、靭性を低下させる。When added in large amounts, toughness decreases.
Ｂ ： ０．００５０％以下
Ｂは焼入性を高め強度上昇に有効な元素であるが、ｏ、
ｏｏｓｏ％超の添加は靭性を低下させる。B: 0.0050% or less B is an element effective in improving hardenability and increasing strength, but o,
Addition of more than ooso% lowers toughness.
さらに、本発明においては鋼の溶接性を確保す２４６
５ ４ １４
を０．３５％以下とした。Furthermore, in the present invention, the weldability of steel is ensured by 246
5 4 14 was set to 0.35% or less.
以上の成分糸からなる鋼を通常の造塊または連鋳法によ
り造塊した後、熱間圧延により所定の板厚まで圧延した
後、空冷もしくはそれ以上の冷速で急冷した鋼板に以下
の熱処理を施す、圧延後の冷力１は特に規定しないが、
可能なかぎり緻密な組織としておくことが強度上好まし
い。After the steel made of the above-mentioned component yarns is made into ingots by normal ingot making or continuous casting method, hot rolled to a predetermined thickness, the steel plate is quenched by air cooling or a faster cooling rate and then subjected to the following heat treatment. The cooling force 1 after rolling is not particularly specified, but
In terms of strength, it is preferable to make the structure as dense as possible.
マｉ’ Ａｃｙ〜＾Ｃ７変態点間のフェライトとオース
テナイトの２相域温度に加熱保持した後、空冷以上温度
で焼入れし、その後＾ｃ１点以下の温度で焼もどしをす
ることにより、低降伏比と高強度を得ようとするもので
ある。After heating and holding at a temperature in the two-phase region of ferrite and austenite between the transformation point of My Acy~^C7, quenching at a temperature higher than air cooling, and then tempering at a temperature lower than the ^C1 point, a low yield ratio is achieved. The aim is to obtain high strength.
ＡＣ１〜＾Ｃ３変態点間のフェライトとオーステナイト
の２相域温度に加熱保持するのは、低降伏比に有効な軟
質のフェライトと高強度化に必要な硬質の硬化Ｉｎ （
オーステナイト相）を得るために必要である。すなわら
、本発明においてはフェライトよりもオーステナイトへ
の溶解度の高いＣ，ＣｕＮｉ （Ｍｎ）等をオーステナ
イト中に十分濃化させるとともに、フェライト中のこれ
らの元素を希釈するためである。オーステナイト中に固
溶したＣｕは、その後の焼入れ、焼もどしで析出強度を
高めるのに寄与する。Heating and maintaining the temperature in the two-phase region of ferrite and austenite between the AC1 and C3 transformation points is to combine soft ferrite, which is effective for low yield ratio, and hardened In, which is necessary for high strength.
austenite phase). That is, in the present invention, C, CuNi (Mn), etc., which have higher solubility in austenite than ferrite, are sufficiently concentrated in austenite, and these elements in ferrite are diluted. Cu dissolved in austenite contributes to increasing precipitation strength during subsequent quenching and tempering.
焼入冷却速度は高強度、高靭性を得るためには急冷はど
望ましい、空冷以下の徐冷却では硬化相（オーステナイ
ト相）で十分な焼入性が得られないため、空冷以上の冷
却とした。For the quenching cooling rate, rapid cooling is preferable in order to obtain high strength and high toughness.Since slow cooling below air cooling does not provide sufficient hardenability in the hardened phase (austenite phase), cooling above air cooling was selected. .
焼入れ強化された脆い硬化相はＡｃ１点以下の焼もどし
処理により靭性を向上できる。The toughness of the brittle hardened phase that has been quenched and strengthened can be improved by tempering to an Ac point of 1 or less.
〈実施例〉
第１表に供試材の化学成分を示す、供試材Ａ〜Ｆ鋼は本
発明の成分範囲内からなる鋼でＣ−Ｊ＠は比較鋼である
。<Example> Table 1 shows the chemical composition of the test materials. Test materials A to F steels are steels having compositions within the range of the present invention, and C-J@ is a comparison steel.
これらの鋼を１１５０℃で６０分加熱後、熱間圧延を９
００°Ｃで終了し、次いで空冷もしくは水冷し、＾Ｃ１
〜＾Ｃｊ点範囲内の温度に加熱し６０分間保持した後、
空冷もしくは水冷で焼入れし、その後５３０〜５６０°
Ｃで６０分間焼もどし処理を行った。これらの機械的性
質を第２表に示す。After heating these steels at 1150°C for 60 minutes, hot rolling was carried out for 9
Finish at 00°C, then air or water cooling, ^C1
~^ After heating to a temperature within the Cj point range and holding for 60 minutes,
Quenched by air cooling or water cooling, then 530-560°
Tempering treatment was performed at C for 60 minutes. Their mechanical properties are shown in Table 2.
本発明法では引張強さ（Ｔ Ｓ ） ６０ｋｇｆ／−以
上で、７８％以下の低降伏比（ＹＲ）が得られている。In the method of the present invention, a tensile strength (T S ) of 60 kgf/- or more and a low yield ratio (YR) of 78% or less are obtained.
Ｙ型溶接割れ試験による割れ防止予熱温度はいずれも２
５゛Ｃ以下で予熱を必要とせず、また、人熱量約７０ｋ
Ｊ／ｃｍのサブマージアーク溶接継手の溶接熱影響部の
シャルピー吸収エネルギーｖ Ｅ −ｓも１６．３ｋｇ
ｆ・ｍ以上と高く、良好な溶接性を有していることがわ
かる。The preheating temperature for preventing cracking in the Y-type weld cracking test was 2 in both cases.
No preheating is required at 5°C or below, and the human heat consumption is approximately 70k.
The Charpy absorbed energy v E -s of the weld heat affected zone of a submerged arc welded joint in J/cm is also 16.3 kg.
It can be seen that it has a high weldability of f·m or more, and has good weldability.
これに対し、比較鋼Ｃ，，ＩＩはＴＳ≧６０ｋｇｆ／ｍ
ＪでＹＲ≦７８％であるが、炭素当量が高いためＹ割れ
防止予熱温度が７５°Ｃ以上と高く、溶接熱影響部の靭
性もｗ Ｅ −Ｓ≦９．４ｋｇｆ −ｍと低い、比較鋼
］では十分な強度が得られず、またＪ＠のようにＮｔを
含有しない鋼では熱間加工性が悪く圧延中に割れが発生
する。On the other hand, comparative steels C, II have a TS≧60kgf/m
Comparative steel, which has YR≦78% in J, but has a high carbon equivalent, so the preheating temperature for preventing Y cracking is high at 75°C or more, and the toughness of the weld heat affected zone is low at w E -S≦9.4kgf -m. ] cannot provide sufficient strength, and steels that do not contain Nt, such as J@, have poor hot workability and cracks occur during rolling.
〈発明の効果〉
本発明によれば、溶接性を良好に維持した状態で、降伏
比８０％以下、引張り強さ６０ｋｇｆ／ｍＪ以−ヒの低
降伏比高張力鋼が製造できるようになった。<Effects of the Invention> According to the present invention, it has become possible to produce a low yield ratio high tensile strength steel with a yield ratio of 80% or less and a tensile strength of 60 kgf/mJ or more while maintaining good weldability. .
Claims (1)
６＋Ｎｉ（％）／４０＋Ｃｒ（％）／５ ＋Ｍｏ（％）／４＋Ｖ（％）／１４ が０．３５％以下に規制され、残部がＦｅ及び不可避的
不純物からなる鋼を、Ａ＿ｃ＿３〜Ａ＿ｃ＿１変態点間
の２相域温度に加熱保持した後、空冷以上の冷却速度で
焼入れし、その後Ａ＿ｃ＿１点以下の温度で焼もどしを
行うことを特徴とする溶接性の良好な低降伏比高張力鋼
の製造方法。 ２ 重量％にて、 Ｃ：０．０３〜０．０８％、 Ｓｉ：０．０５〜１．２０％、 Ｍｎ：０．５０〜１．６０％、 Ｃｕ：０．８０〜２．５０％、 Ｎｉ：０．４０〜２．００％、 Ｐ：０．０３０％以下、 Ｓ：０．０２０％以下、 Ｎ：０．００６０％以下 を含有し、さらに Ｃｒ：０．５０％以下、 Ｍｏ：０．５０％以下、 Ｖ：０．０６％以下、 Ｎｂ：０．０４０％以下、 Ｂ：０．００５０％以下、 Ｔｉ：０．０６０％以下 の１種以上を含み、かつ Ｃｅｑ．＝Ｃ（％）＋Ｓｉ（％）／２４＋Ｍｎ（％）／
６＋Ｎｉ（％）／４０＋Ｃｒ（％）／５ ＋Ｍｏ（％）／４＋Ｖ（％）／１４ が０．３５％以下に規制され、残部がＦｅ及び不可避的
不純物からなる鋼を、Ａ＿ｃ＿１〜Ａ＿ｃ＿３変態点間
の２相域温度に加熱保持した後、空冷以上の冷却速度で
焼入れし、その後Ａ＿ｃ＿１点以下の温度で焼もどしを
行うことを特徴とする溶接性の良好な低降伏比高張力鋼
の製造方法。[Claims] At 1% by weight, C: 0.03 to 0.08%, Si: 0.05 to 1.20%, Mn: 0.50 to 1.60%, Cu: 0.80 ~2.50%, Ni: 0.40~2.00%, P: 0.030% or less, S: 0.020% or less, N: 0.0060% or less, and Ceq. =C(%)+Si(%)/24+Mn(%)/
6 + Ni (%) / 40 + Cr (%) / 5 + Mo (%) / 4 + V (%) / 14 is regulated to 0.35% or less, and the balance is Fe and unavoidable impurities. A method for manufacturing a low yield ratio high tensile strength steel with good weldability, characterized by heating and holding at a two-phase region temperature of , quenching at a cooling rate higher than air cooling, and then tempering at a temperature below A_c_1 point. . At 2% by weight, C: 0.03-0.08%, Si: 0.05-1.20%, Mn: 0.50-1.60%, Cu: 0.80-2.50%, Contains Ni: 0.40 to 2.00%, P: 0.030% or less, S: 0.020% or less, N: 0.0060% or less, further Cr: 0.50% or less, Mo: 0 .50% or less, V: 0.06% or less, Nb: 0.040% or less, B: 0.0050% or less, Ti: 0.060% or less; =C(%)+Si(%)/24+Mn(%)/
6 + Ni (%) / 40 + Cr (%) / 5 + Mo (%) / 4 + V (%) / 14 is regulated to 0.35% or less, and the balance is Fe and unavoidable impurities. A method for manufacturing a low yield ratio high tensile strength steel with good weldability, characterized by heating and holding at a two-phase region temperature of , quenching at a cooling rate higher than air cooling, and then tempering at a temperature below A_c_1 point. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21506889A JPH0379716A (en) | 1989-08-23 | 1989-08-23 | Manufacture of low yield ratio high tensile strength steel having good weldability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21506889A JPH0379716A (en) | 1989-08-23 | 1989-08-23 | Manufacture of low yield ratio high tensile strength steel having good weldability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0379716A true JPH0379716A (en) | 1991-04-04 |
Family
ID=16666225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21506889A Pending JPH0379716A (en) | 1989-08-23 | 1989-08-23 | Manufacture of low yield ratio high tensile strength steel having good weldability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0379716A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994010355A1 (en) * | 1992-10-30 | 1994-05-11 | Japan Casting & Forging Corporation | High-strength hot-rolled steel sheet excellent in uniform elongation after cold working and process for producing the same |
| CN112063816A (en) * | 2019-06-10 | 2020-12-11 | 育材堂（苏州）材料科技有限公司 | Heat treatment method of high-strength steel and product obtained thereby |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63286517A (en) * | 1987-05-19 | 1988-11-24 | Nippon Steel Corp | Manufacture of high-tensile steel with low yielding ratio |
-
1989
- 1989-08-23 JP JP21506889A patent/JPH0379716A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63286517A (en) * | 1987-05-19 | 1988-11-24 | Nippon Steel Corp | Manufacture of high-tensile steel with low yielding ratio |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5509977A (en) * | 1992-01-30 | 1996-04-23 | Japan Casting & Forging Corporation | High strength hot rolled steel plates and sheets excellent in uniform elongation after cold working and process for producing the same |
| WO1994010355A1 (en) * | 1992-10-30 | 1994-05-11 | Japan Casting & Forging Corporation | High-strength hot-rolled steel sheet excellent in uniform elongation after cold working and process for producing the same |
| CN112063816A (en) * | 2019-06-10 | 2020-12-11 | 育材堂（苏州）材料科技有限公司 | Heat treatment method of high-strength steel and product obtained thereby |
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