JPH02133521A - Production of tempered high tensile steel plate having excellent toughness - Google Patents
Production of tempered high tensile steel plate having excellent toughnessInfo
- Publication number
- JPH02133521A JPH02133521A JP28708488A JP28708488A JPH02133521A JP H02133521 A JPH02133521 A JP H02133521A JP 28708488 A JP28708488 A JP 28708488A JP 28708488 A JP28708488 A JP 28708488A JP H02133521 A JPH02133521 A JP H02133521A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- less
- strength
- steel plate
- rolling
- 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 58
- 239000010959 steel Substances 0.000 title claims abstract description 58
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000005096 rolling process Methods 0.000 claims abstract description 29
- 238000001816 cooling Methods 0.000 claims abstract description 22
- 238000003303 reheating Methods 0.000 claims abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000005496 tempering Methods 0.000 claims abstract description 7
- 230000001186 cumulative effect Effects 0.000 claims abstract description 4
- 230000000171 quenching effect Effects 0.000 claims description 30
- 238000010791 quenching Methods 0.000 claims description 29
- 230000009467 reduction Effects 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims 1
- 229910052742 iron Inorganic materials 0.000 claims 1
- 229910052758 niobium Inorganic materials 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 26
- 229910000734 martensite Inorganic materials 0.000 description 13
- 239000000463 material Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 238000005336 cracking Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 5
- 238000003466 welding Methods 0.000 description 5
- 230000007704 transition Effects 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 239000010953 base metal Substances 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 210000003127 knee Anatomy 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 235000015429 Mirabilis expansa Nutrition 0.000 description 1
- 244000294411 Mirabilis expansa Species 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 210000003746 feather Anatomy 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 235000013536 miso Nutrition 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002759 woven fabric 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〉
この発明は、降伏強度：９０ｋｒｆ／−以上、引張強度
：９７ｋｒｆ／−以上並びに衝撃遷移温度ニー６０℃以
下の性能を有する高張力鋼板の製造方法に係り、特に、
上記性能を有する板厚＝４０鶴以上の厚肉高張力鋼板を
安定して量産するのに好適な調質型高張力鋼板の製造方
法に関するものである。Detailed Description of the Invention <Industrial Application Field> This invention is directed to the production of high-strength steel sheets having yield strength of 90 krf/- or more, tensile strength of 97 krf/- or more, and impact transition temperature of 60° C. or less. Regarding the method, in particular,
The present invention relates to a method for manufacturing a heat-treated high-tensile steel plate suitable for stably mass-producing thick-walled high-strength steel plates having the above-mentioned performance and having a thickness of 40 mm or more.
〈従来技術とその課題〉
近年、溶接構造物の大型化傾向は益々著しくなっており
、これらに使用される構造用鋼板はより−層のハ・イテ
ン化並び１こ厚肉化の一途をたどっている。例えば、揚
水発電所の水圧鉄管に１８０ｎｍ厚の８０ｋｇｆ／ｍｉ
級高張力目板が使用されたり、ジャキアソブリグ型石油
掘削リグのう・ツク材に１００〜１．５０ ｍｍ厚の８
０ｋｇｆ／−級高張力釦板が使用されたりするに至って
いる。<Prior art and its problems> In recent years, the tendency for welded structures to become larger has become more and more remarkable, and the structural steel plates used for these are becoming increasingly thicker and higher in thickness. ing. For example, 80kgf/mi of 180nm thickness is applied to the penstock of a pumped storage power plant.
Grade high tensile battens are used, and 100 to 1.50 mm thick 8.
0 kgf/- class high tension button plates have come to be used.
しかしなから、現在のところ一般的に使用されている高
張力鋼板は６０ｋｇｆ／−級材及び８０ｋｇｆ／−級材
に留まっており、大型化が著し、い近年の）容接構造物
に対してより強度の高い高張力鋼板の適用が望まれてい
るにも係わらず未だ１００ ｋｇｆ／ａ４級材の使用に
は至っていない。これは、厚肉鋼板において
ａ）降伏強度：９０ｋｇｆ／−以」二、引張強度：９７
ｋｇ ｆ ／−以上と言う１００ ｋｇｆ／ｎ＋ｎ）級
材の要求強度を工業的に安定して確保することが困難で
ある。However, the high tensile strength steel plates commonly used at present are limited to 60 kgf/- grade materials and 80 kgf/- grade materials, and are not suitable for use in capacitive structures (in recent years), which have become significantly larger. Although it is desired to use high-strength steel plates with higher strength, 100 kgf/A4 grade materials have not yet been used. This is for thick steel plates: a) Yield strength: 90 kgf/- or more, and Tensile strength: 97
It is difficult to industrially stably secure the required strength of 100 kgf/n+n) grade material, which is 100 kgf/n+n) or more.
ｂ）例えこのような高強度を付与し得たとしても、同時
に十分な低温靭性をも確保することはより一層困難であ
る。b) Even if such high strength could be imparted, it would be even more difficult to ensure sufficient low-temperature toughness at the same time.
Ｃ）更に、該綱板に溶接施工上問題とならないだけの良
好な溶接性を付与することも極めて困難である。C) Furthermore, it is extremely difficult to provide the steel plate with good weldability that does not pose a problem in welding work.
等の問題点が克服できなかったことによるものである。This is because the following problems could not be overcome.
つまり、４０■厚を超える板厚の１００ ｋｇｆ／ａ＋
＋＋１級高張力極厚鋼板売高張力極厚鋼板ては、板厚中
心部の強度確保を図るために焼入れ性の高い成分設計を
行う必要があるが、厚内材のため焼入れに際しての表層
部と中心部との冷却速度に大きな差が生じ、中心部の強
度を確保しようとすると表層部の強度が高くなり過ぎて
低温靭性が中心部より著しく劣化する結果となる。更に
、上記方針の下で設計された成分系の鋼では炭素当１（
Ｃｅｑ）が高＜７尿ってしまうので溶接性にも問題が生
してしまう。そのため、４０ｎ＋厚を超える肉厚の１０
０ｋｇｆ／−扱高強度高靭性厚肉鋼板を溶接性の問題グ
ζしに安定製造し得る手段を見出すことが、この分野に
おける最大の課題の一つとなっていた。In other words, 100 kgf/a+ of plate thickness exceeding 40 ■ thickness
++1 class high tensile strength extra thick steel plate Sales Tensile extra thick steel plate requires composition design with high hardenability in order to ensure strength in the center of the plate thickness, but since it is a thick inner material, the surface layer part during quenching There is a large difference in the cooling rate between the core and the core, and if the strength of the core is to be ensured, the strength of the surface layer becomes too high, resulting in significantly worse low-temperature toughness than that of the core. Furthermore, steels with compositions designed under the above policy have a carbon content of 1 (
Ceq) is high < 7, which causes problems in weldability. Therefore, if the wall thickness exceeds 40n+
One of the biggest challenges in this field has been to find a means to stably manufacture high-strength, high-toughness, thick-walled steel plates that can handle 0 kgf/- without weldability problems.
〈課題を解決するための手段〉
そこで、本発明者等は上述のような観点から、降伏強ｅ
： ９０ ｋｇｆ／ｍ＋ｄ以上、引張強度：９７ｋｇ
ｆ／−以上及び衝Ｈａ移温度ニー６０℃以下の性能を有
し、特に板ｊ〃が４０＋＋ｍを超える場合にも前記性能
を安定し２て（＝Ｊ与することができる（〃内高張力鋼
板の製造手段を提供すべく鋭、音研究を重ねた結果、次
に示す如き知見を得るに至った。即ち、（ａ） 所望
の溶接性を確保した上でコスト的にも実用的な１００
ｋｇｆ／ｍｕ！級の高張力ｉ４を得るには強化元素の多
量添加手段等は不適当であり、溶接割れ感受性指数（ｐ
ｃｎ）を０．３１以下に抑えた成分系の素ｊｉＡ鋼を
用い、焼入れにより鋼材組織をマルテンサイト組織化す
ることが欠か・仕ないこと（ｂｌ Ｌかし、厚肉綱板
を焼入れする場合には板厚中心部と表面部とで冷却速度
にどつしても差が生じてしまうため、中心部での十分な
強度確保を図ると表面部では焼きが入りすぎて低温靭性
の劣化を招くが、この際、焼入れ時のγ粒径を極力小さ
くすることによって細粒のマルテンサイト組織が得られ
るような手直てを講じると、焼きがｉＱｍ：になりがち
な鋼材表面部においても十分に満足できる低温靭性が維
持され、厚内高張力ｉ；１仮に必要な“板）Ｖ方向全体
に亘−９ての良好な強度−靭性ハランス”が確保される
こと
（Ｃ） そして、焼入れ時に所望の細粒γ粒を実現す
るためには、Ｎｂ添加によって鋼材加熱時におりＪるγ
粒の成長を抑制すると同時に、事前に一旦焼入れ処理を
施しで加熱部組れｋ（ｙ生前の組織）の微細化を図って
おくのが極めて有効であり、このｆＪｌ）添加と二回焼
入れによる相乗効果を活用すれば、細粒のＴ粒を経て極
めて微細なマルテンナイＩＩ；ＩＩ織の確保が安定して
可能となること。<Means for Solving the Problem> Therefore, from the above-mentioned viewpoint, the present inventors have determined the yield strength e.
: 90 kgf/m+d or more, tensile strength: 97 kg
It has the performance of f/- or higher and the tension Ha transfer temperature knee of 60°C or lower, and in particular, even when the plate j exceeds 40++ m, the above performance can be stabilized and given (=J). As a result of extensive sound research in order to provide a means for manufacturing steel plates, we have come to the following findings: (a) A 100% welding method that ensures the desired weldability and is cost-effective.
kgf/mu! In order to obtain high tensile strength i4, it is inappropriate to add large amounts of reinforcing elements, and the weld cracking susceptibility index (p
It is indispensable to make the steel structure into a martensitic structure by quenching, using a raw steel with a component system that suppresses cn) to 0.31 or less (bl L) When quenching thick steel plates. There is always a difference in the cooling rate between the center of the plate thickness and the surface, so if you try to ensure sufficient strength at the center, the surface will become too hard and the low-temperature toughness will deteriorate. However, if you take measures to obtain a fine-grained martensitic structure by reducing the γ grain size as much as possible during quenching, the quenching will be sufficient even on the steel surface where iQm: tends to occur. Satisfactory low-temperature toughness is maintained, and high in-thickness tensile strength i; In order to achieve the desired fine γ grains, it is necessary to add Nb to reduce the amount of γ that is released during heating of the steel material.
At the same time as suppressing the growth of grains, it is extremely effective to perform a quenching process in advance to refine the heated part structure k (y structure before birth). By utilizing the synergistic effect, it is possible to stably secure an extremely fine Martenai II/II weave through fine T grains.
（ｔｊ） ただ、この場合、第一回目焼入れは熱間圧
延に引き続いてそのまま実施する直接焼入れによること
が工業的に有利であること
（ｅ）また、第二回目焼入れ前のγ粒を微細に保つには
第ニー回目焼入れを比較的低温のＴ域から行うのが良い
上、溶接性の観点から鋼のＰＣＭを０．３１以下に抑え
る必要があるため、焼入れの効果が不十分となって１０
０ｋｇｆ／ｍｎｔ級の強度が確保できなくなる懸念もあ
るが、この問題は焼入れ性向上元素であるＢの添加によ
り極めて効果的に解消されること。(tj) However, in this case, it is industrially advantageous to perform the first quenching by direct quenching directly following hot rolling. In order to maintain the condition, it is better to perform the second quenching from the T range at a relatively low temperature, and from the viewpoint of weldability it is necessary to suppress the PCM of the steel to 0.31 or less, so the quenching effect is insufficient. 10
Although there is a concern that a strength of 0 kgf/mnt class may not be secured, this problem can be resolved extremely effectively by adding B, which is an element that improves hardenability.
本発明は、ｒ １００ ｋｇｆ／ｍｄ級の厚肉高張力鋼
にて優れた低温靭性を実現するためには細粒なオステナ
イトＤ）粒から変態したマルテンサイト組織を得ること
が重要であり、また溶接性の低下を伴うことなく高強度
を得るための焼入れ性向トを図るにはＢが有する焼入れ
性改善効果の活用が欠かせなし司との認識を強めた上記
知見等に基づく更なる研究によって完成されたものであ
り、Ｉ’ Ｃ： ０．０８〜０．２０％（以降、成分割
合を表わず％は重量％とする）。In the present invention, in order to achieve excellent low-temperature toughness in r100 kgf/md class thick-walled high-strength steel, it is important to obtain a martensitic structure transformed from fine-grained austenite D) grains, and Through further research based on the above findings, we have strengthened the recognition that it is essential to utilize the hardenability improving effect of B in order to increase the hardenability to obtain high strength without deteriorating weldability. It is a completed product, and I'C: 0.08 to 0.20% (hereinafter, the component ratio is not expressed and % is expressed as weight %).
Ｓｉ ： ０．３０％以下、 Ｍｎ ： ０．４０〜
１．２０％Ｃｕ ： ０．５％以下、 Ｎｉ ：
０．４０〜３．５０％。Si: 0.30% or less, Mn: 0.40~
1.20%Cu: 0.5% or less, Ni:
0.40-3.50%.
Ｃｒ ： ０．１０〜１．２０％、 Ｍｏ ： ０．
０５〜０．８％Ｖ ： ０．００５〜・０．１％、
Ｎｂ ： ０．００５〜０．０３％。Cr: 0.10-1.20%, Mo: 0.
05~0.8%V: 0.005~・0.1%,
Nb: 0.005-0.03%.
ｓｏｌ、 ＡＪ！ ： ０．０１〜０．１０％。Sol, AJ! : 0.01-0.10%.
Ｂ ： ０．０００３〜０．００３０％、 ｐ：ｏ、
ｏｉ％以下。B: 0.0003-0.0030%, p:o,
oi% or less.
Ｓ：０．００５％以下、 Ｎ ： ０．００４％以
下で残部が実質的にＦｅから成り、かっ式％式％）
：）
にて表わされるＰＣＭが０．３１％以下である鋼を、第
１図で示すように１０００℃以上に加熱して熱間圧延し
、９００℃以上の温度域において３０％以上の累積圧下
を与えると共に８００°Ｃ以」二の温度域から所定板ｙ
￥に仕上圧延した後、そのまま板厚中心部の冷却速度：
３℃７ｓｅｃ以上で６００℃以下にまで冷却し、次いで
Ａｃ３点〜９５０”Ｃの温度域に再加熱して水焼入れを
行い、引き続いてＡｅ、意思下の温度で焼戻しすること
により、板厚が４゜１ｍ厚を超えるものであっても降伏
強度：９０ｋｇｆ／−以上、引張強度：９７ｋｇｆ／−
以上並びに術？遷移温度ニー６０℃以下の性能を安定し
て示す上、良好な溶接性をも有する高張力鋼板を］−業
的規模で量産し得るようにした点」に特徴を有している
。S: 0.005% or less, N: 0.004% or less, the remainder substantially consists of Fe, and the PCM expressed by the parentheses % formula %):) is 0.31% or less. As shown in Figure 1, hot rolling is carried out by heating to a temperature of 1000°C or higher, applying a cumulative reduction of 30% or more in a temperature range of 900°C or higher, and rolling a predetermined sheet from a temperature range of 800°C or higher.
After finishing rolling to ¥, the cooling rate at the center of the plate thickness:
The board is cooled to 600°C or less over 3°C for 7 seconds, then reheated to a temperature range of Ac3 to 950"C for water quenching, and then Ae and tempered at the desired temperature to reduce the plate thickness. Even if the thickness exceeds 4゜1m, yield strength: 90kgf/- or more, tensile strength: 97kgf/-
Above and more techniques? It is characterized by the ability to mass-produce high-strength steel sheets on an industrial scale that stably exhibit performance with a transition temperature of 60° C. or lower and also have good weldability.
次に、本発明において高張力鋼板の製造条件を前記の如
くに限定した理由を、その裏付けとなった作用と共に説
明する。Next, the reason why the manufacturing conditions of the high-strength steel plate are limited as described above in the present invention will be explained together with the effects that supported the manufacturing conditions.
〈作用〉
Ａ）素材鋼の成分組成
ａ） Ｃ
Ｃは鋼板の強度を確保する−１−で必要な元素であるが
、その含有■が０，０８％未満ではｌ ００ ｋｇｆ／
＋ｎｄ扱高張力泪としての必要強度を確保することがで
きず、一方、０．２０％を超えて含有させると溶接低温
割れを生じるようになることから、Ｃ含有量は０．０８
〜０．２０％と定めた。<Function> A) Composition of material steel a) C C is a necessary element in -1- to ensure the strength of the steel plate, but if its content (■) is less than 0.08%, l 00 kgf/
The C content is 0.08% because it is not possible to secure the necessary strength for high tensile strength, and on the other hand, if the content exceeds 0.20%, welding cold cracking will occur.
It was set at ~0.20%.
１）） Ｓｉ
通常、Ｓｉは鋼の脱酸と強度確保のために添加される元
素であるが、脱酸の効果は含有量が０．３０％を超える
と飽和傾向を示す。一方、強度については含有量が０．
３０％を超えても上昇するが、このような多量の添加は
比較的冷却速度の速い溶接継手部において島状マルテン
サイトを生成させ、溶接相手部靭性を低下させる。この
ため、Ｓｉ含有砒は０．３０％以下と定めた。1)) Si Usually, Si is an element added to deoxidize steel and ensure strength, but the deoxidizing effect tends to be saturated when the content exceeds 0.30%. On the other hand, regarding strength, the content is 0.
Although it increases even when it exceeds 30%, addition of such a large amount causes island-shaped martensite to be generated in the welded joint where the cooling rate is relatively fast, reducing the toughness of the welding partner part. For this reason, the Si-containing arsenic content was determined to be 0.30% or less.
ｃ） Ｍｎ
Ｍｎ成分には羽の脱酸剤としての作用のほか、焼入性を
確保する作用があるが、その含有量が０．４０％未満で
は前記作用による所望の効果が得られず、一方、１−２
０９４４を超えて含有させると溶接性及び母材靭性の劣
化を招くことから、Ｍｎ含有量を０．４０・−１，２０
％と定めた。c) Mn In addition to acting as a feather deoxidizing agent, the Mn component also has the effect of ensuring hardenability, but if its content is less than 0.40%, the desired effect due to the above effect cannot be obtained, On the other hand, 1-2
Since Mn content exceeding 0.0944 causes deterioration of weldability and base metal toughness, the Mn content is set to 0.40・-1,20.
%.
ｄ） Ｃｕ
Ｃｕは靭性を損なうことなく強度を高めるのに有効な元
素であり、微量の添加によっても該効果が６ｍ認できる
が、０．５％を超えて添加してもコストアップに見合う
だけの強度上昇効果が得られないばかりか、高／Ｉ！！
延性に悪影響を及ぼし、連鋳スラブの表面別れを生じて
鋼材の歩留を低下させるようになることから、Ｃｕ含有
計は０．５％以下と定めた。d) Cu Cu is an effective element for increasing strength without impairing toughness, and this effect can be seen even when added in a trace amount, but adding more than 0.5% is only worth the cost increase. Not only is the strength-increasing effect not obtained, but also high/I! !
The Cu content was determined to be 0.5% or less because it adversely affects ductility and causes surface separation of the continuously cast slab, reducing the yield of steel products.
ｅ） Ｎｉ
Ｎｉ成分には鋼の焼入れ性確保と低温靭性の改を１作用
があるが、その含有量が０．４０％未満では４０重１厚
以上の１００ｋｇＦ／−級高張力泪板に必要強度を確保
することができず、一方、３．５０％を超えて添加して
もコストアップに見合うだけの強度上昇と靭性改善の効
果が得られないため、Ｎｉ含有量は０．４０〜３．５０
％と定めた。e) Ni The Ni component has the function of ensuring the hardenability of steel and improving the low-temperature toughness, but if its content is less than 0.40%, it is necessary for 100 kgF/- class high tensile strength steel plates of 40 weight and 1 thickness or more. On the other hand, even if it is added in excess of 3.50%, the effect of increasing strength and improving toughness that is commensurate with the cost increase cannot be obtained, so the Ni content is 0.40 to 3. .50
%.
ｆ） Ｃｒ
Ｃ「成分には鋼の焼入性と強度を確保する作用があるが
、その含有量が０．１０％未満では前記作用による所望
の効果が得られず、一方、１．２０％を超えて含有させ
ると溶接性に悪影響を及ぼすようになることから、Ｃｒ
含有量は０．１０〜１．２０％と定めた。f) CrC component has the effect of ensuring the hardenability and strength of steel, but if its content is less than 0.10%, the desired effect of the above effect cannot be obtained; If the content exceeds Cr, it will have a negative effect on weldability.
The content was determined to be 0.10 to 1.20%.
ｇ） Ｍ。g) M.
Ｍｏは鋼の焼入性を増加させると共に、焼戻し軟化抵抗
を高めて所望強度を確保する上で有効な元素であるが、
その含有量が０．０５％未満では十分な前記効果が得ら
れず、一方、０．８％を超えて含有させても強度」二昇
の効果が飽和傾向を示すだけでなく溶接性を著しく劣化
させることから、Ｍｏ含有債は０．０５〜０．８％と定
めた。Mo is an effective element for increasing the hardenability of steel and increasing temper softening resistance to ensure desired strength.
If the content is less than 0.05%, sufficient effects cannot be obtained; on the other hand, if the content exceeds 0.8%, the effect of increasing strength not only tends to be saturated but also significantly reduces weldability. Since it causes deterioration, the Mo-containing bond is set at 0.05 to 0.8%.
ｈ） Ｖ
■は鋼に強度を確保のために添加される元素であるが、
その含有量が０．００５％未満では所望強度の確保が困
難であり、一方、０．１％を超えて含有させると母材靭
性及び溶接性を著しく劣化させることから、■含有量は
０．００５−０．１％と定めた。h) V ■ is an element added to steel to ensure strength,
If the content is less than 0.005%, it is difficult to secure the desired strength. On the other hand, if the content exceeds 0.1%, the toughness and weldability of the base material will be significantly deteriorated. 005-0.1%.
ｉ） Ｎｂ
Ｎｂ成分には、微細析出物としてオーステナイト（ｒ）
領域に存在することにより、そのピン止め効果によって
オーステナイト粒の成長を抑制しオーステナイト粒を細
粒化する作用があるが、Ｎｌｌ含存量が０．００５％未
満では前記作用による所望の効果が得られず、一方、０
．０３％を超えて含有させると溶接性を著しく１員なう
ようになることから、Ｎｂ含有■は０．００５へ−０，
０３％と定めた。i) Nb The Nb component contains austenite (r) as fine precipitates.
By existing in the region, the pinning effect suppresses the growth of austenite grains and makes the austenite grains finer. However, if the Nll content is less than 0.005%, the desired effect due to the above action cannot be obtained. zu, on the other hand, 0
．． If the Nb content exceeds 0.03%, weldability will be significantly affected, so the Nb content will be reduced to 0.005 -0,
It was set at 0.3%.
ｊ） ｓｏｆ、ＡＪ！
ＡＩ酸成分は鋼の脱酸作用と共にオーステナイト粒を微
細化して靭性を向」ニさせる作用があるが、その含有量
が０．０１％未満では前記作用による所望の効果が得ら
れず、一方、０．１０％を超えて含有させると逆にアル
ミナ等の脱酸生成物増加により靭性が損なわれるように
なることから、ｓｏｆ、ＡＲ含有量を０．０１〜０．１
０％と定めた。j) sof, AJ! The AI acid component has the effect of deoxidizing the steel as well as refining the austenite grains and improving the toughness, but if the content is less than 0.01%, the desired effect due to the above effect cannot be obtained; If the content exceeds 0.10%, the toughness will be impaired due to an increase in deoxidation products such as alumina, so the sof and AR content should be set to 0.01 to 0.1.
It was set as 0%.
ｋ） Ｂ
Ｂは微量添加で大幅に鋼の焼入性を向上させる元素であ
り、鋼の強度・靭性を向上させるのに非常に有効な成分
であるが、その含有量が０．０００３％未満では鋼に所
望の強度・靭性を確保することができず、一方、０．０
０３％を超えて含有させてもその効果が飽和することか
ら、Ｂ含ＹＭ’ ５＋−！、ま０．０００３〜０．００
３９／６と定めた。k) B B is an element that significantly improves the hardenability of steel when added in small amounts, and is a very effective component for improving the strength and toughness of steel, but if its content is less than 0.0003% However, on the other hand, with 0.0
Since the effect is saturated even if the content exceeds 0.03%, B-containing YM' 5+-! , ma0.0003~0.00
It was set as 39/6.
１） Ｐ
■）は鋼の焼戻し脆性を促進して靭性を劣化させる不純
物元素である。特に高強度鋼ではその影響を受けやすい
。ただ、Ｐ含有量を０．０１％以下に抑えることによっ
て前記悪影舌が容認し得る程度に抑制されることから、
Ｐ含有量は０．ｆ）１９％以下と限定した。1) P (2) is an impurity element that promotes temper brittleness of steel and deteriorates toughness. High-strength steel is particularly susceptible to this effect. However, by suppressing the P content to 0.01% or less, the bad tongue can be suppressed to an acceptable level.
P content is 0. f) It was limited to 19% or less.
ｍ） Ｓ
Ｓは、通常、鋼中においてＭｉｓＯ形１虚で存在し、圧
延により展伸されて靭性の異方性を生じる不純物元素で
ある。そして、高強度錫１に打いては特に展伸した介在
物が著しい靭性劣化の原因となるが、Ｓ含有量を０．０
０５％以下に抑えることによって該悪影古を容認し得る
程度に抑制されることから、Ｓ含有量は０．００５％以
下と限定した。m) S S is an impurity element that normally exists in the MisO form in the 1-imaginary form in steel and is elongated by rolling to cause anisotropy in toughness. When hammered into high-strength tin 1, elongated inclusions in particular cause a significant deterioration of toughness, but the S content was reduced to 0.0
By suppressing the S content to 0.05% or less, the adverse effects can be suppressed to an acceptable level, so the S content was limited to 0.005% or less.
ｎ） Ｎ
Ｎをｏ、ｏｏ、ｉ％以下にすることは、鋼の焼入性を高
め母材の強度と靭性向上に極めて有効な手段である。即
ち、Ｎ含有量を０．００４％以下にすると共にｓｏｆ、
Ａｊ’含有量を０．０１〜０．１０％に調整することに
よって固溶Ｂｉを０．０００３％以上とすることができ
、焼入性の著しい向上が達成される。また、Ｎｌを０．
００４％以下に低減すると＾ｉ’Ｎの粗大化が抑制され
て靭性も向上する。更に、低Ｎ化によってＶＮの生成が
抑制されるので通常のオーステナイト化温度で■が均一
固溶するようになり、従って■の添加量を削減できる効
果も確保できる。このようなことから、Ｎ含有量は０．
００４％以下と限定した。n) N Setting N to less than o, oo, i% is an extremely effective means for increasing the hardenability of steel and improving the strength and toughness of the base metal. That is, while reducing the N content to 0.004% or less, sof,
By adjusting the Aj' content to 0.01 to 0.10%, the solid solution Bi can be made 0.0003% or more, and a significant improvement in hardenability is achieved. Also, Nl was 0.
When it is reduced to 0.004% or less, coarsening of ^i'N is suppressed and toughness is also improved. Furthermore, since the generation of VN is suppressed by reducing the N content, (2) becomes a uniform solid solution at a normal austenitizing temperature, and therefore, the effect of reducing the amount of (2) added can also be secured. For this reason, the N content is 0.
It was limited to 0.004% or less.
０）溶接割れ感受性指数（Ｐｃ、４〕
Ｐ ＣＭ ＝ Ｃ（χ） ＋Ｓｉ（％）／３０＋Ｍｎ（
χ）／２０＋Ｃｕ（％）／２０＋Ｎｉ（’り／６０＋Ｃ
ｒ（χ）／２０ ＋ Ｍｏ （Ｘ） ／ １５＋Ｖ（χ
）／１０４５ Ｍ Ｂ （χ）で表わされるＰＣＭが０
．３１％を超えた場合には溶接性が著しく劣化し、実用
上問題となることから、上記Ｐｃイを０，３１％以下と
定めた。0) Weld cracking susceptibility index (Pc, 4) P CM = C (χ) + Si (%) / 30 + Mn (
χ)/20+Cu(%)/20+Ni('ri/60+C
r(χ)/20+Mo(X)/15+V(χ
)/1045 M B (χ) PCM is 0
．． If it exceeds 31%, the weldability will deteriorate significantly and pose a practical problem, so the above-mentioned Pc is set at 0.31% or less.
Ｂ）圧延・熱処理条件
ａ）圧延加熱温度
圧延に際しては■炭窒化物やＢＮ等の固溶を図るために
高温加熱することが望まれるが、該加熱温度が１ｏｏｏ
℃未満では上記析出物の十分な固溶がなされないことか
ら、圧延加熱温度は１０００℃以北と定めた。B) Rolling/Heat Treatment Conditions a) Rolling Heating Temperature During rolling, it is desirable to heat to a high temperature in order to solidly dissolve carbonitrides, BN, etc.
Since sufficient solid solution of the above-mentioned precipitates is not achieved at a temperature lower than 1000°C, the rolling heating temperature was determined to be north of 1000°C.
ｂ） 圧延圧下量
良好な溶接性を有する４０韮厚以上の厚内高靭性高張力
鋼板をも安定して製造できるようにするのが本発明の狙
いであるが、肉厚鋼板の場合には所定厚までの加工では
鍛錬比不足となって十分な細粒化を図れないことがある
。そして、本発明においては細粒のマルテンサイト組織
を得ることが重要なポイントであるため、先にも述べた
ようにその前組織をできるだけ均一微細にしておく必要
がある。このためには９００℃以上の温度域で３０％以
」−の圧下を加える必要があり、従って直接焼入れを適
用する場合は１粒の再結晶を促進すべく９００℃以上の
温度域で３０％以上の累積圧下を与えることと定めた。b) Rolling reduction amount The aim of the present invention is to be able to stably produce high-toughness, high-strength steel plates with a thickness of 40 mm or more that have good weldability.However, in the case of thick steel plates, When processing to a predetermined thickness, the forging ratio may be insufficient and sufficient grain refinement may not be achieved. In the present invention, it is important to obtain a fine-grained martensitic structure, so as mentioned above, it is necessary to make the pre-structure as uniform and fine as possible. For this purpose, it is necessary to apply a reduction of 30% or more in a temperature range of 900°C or higher. Therefore, when applying direct quenching, a reduction of 30% or more must be applied in a temperature range of 900°C or higher to promote recrystallization of a single grain. It was decided that a cumulative pressure of more than 100% was to be applied.
Ｃ）圧延仕上温度及び急冷条件
本発明は、特定成分組成鋼を８００℃以上の温度域で所
定の板厚に仕上圧延し、圧延後６００℃以下の温度にま
で急冷（例えば水冷）することを特徴としているが、こ
れは、引き続く再加熱焼入れの際に該再加熱の前の組織
がマルテンサイト或いはベイナイトと言う焼入れ組織に
なっていると再加熱時におけるα−丁逆変態でのγの核
生成ザ１トの数がフェライト＋パーライト組織の場合に
比較して多く生じるので、γ生後の粒成長時にそれらが
互いに衝突して成長が阻害され、結局得られる粒径が小
さくなるとの事実に基づいた条件である。つまり、最終
組織を細粒のマルテンサイト′１ｌＪ１へとするのに必
要な「再加熱時のγ粒を細粒化する」との条件を達成す
るためには、再加熱前の状態ではフェライトの生成を抑
制しておくことが重要である。そこで、圧延中にフェラ
イトの生成を起こさせないためγ域である８００℃以上
の温度で圧延を仕上げる必要があり、圧延後の冷却中に
おけるフェライトの生成を抑制してマルテンサイト或い
はベイナイ）ｕ織にするためには圧延終了後そのま土６
００℃以下の温度にまで急冷（水冷等）することを要す
る。この場合、仕上圧延温度が８００ ’ｃ未満であっ
たり、圧延後の冷却速度が板厚中心部で３°Ｃ／ｓｅｃ
よりも遅かったり、或いは急冷停止温度が６００ ｃよ
りも高かったりすると所望のマルテンサイト又はベイナ
イト組織が得られず、続く再加熱において生成するγ粒
が微細とはならない。C) Finishing rolling temperature and quenching conditions The present invention involves finishing rolling a steel with a specific composition to a predetermined thickness in a temperature range of 800°C or higher, and then rapidly cooling (for example, water cooling) to a temperature of 600°C or lower after rolling. This is characterized by the fact that during subsequent reheating and quenching, if the structure before the reheating is a quenched structure called martensite or bainite, γ nuclei in the α-tiny reverse transformation during reheating. This is based on the fact that since the number of particles generated is larger than in the case of ferrite + pearlite structure, they collide with each other during grain growth after γ, inhibiting growth, and ultimately resulting in a smaller grain size. These are the conditions. In other words, in order to achieve the condition of "refining the γ grains during reheating," which is necessary to make the final structure into fine-grained martensite '1lJ1, it is necessary to It is important to suppress generation. Therefore, in order to prevent the formation of ferrite during rolling, it is necessary to finish the rolling at a temperature of 800°C or higher, which is the γ range, and suppress the formation of ferrite during cooling after rolling to form a martensite (or baini) U-woven fabric. In order to do this, leave the soil as it is after rolling 6
It is necessary to rapidly cool (water cooling, etc.) to a temperature of 00°C or less. In this case, the finish rolling temperature is less than 800'C or the cooling rate after rolling is 3°C/sec at the center of the plate thickness.
If the quenching temperature is lower than 600° C. or if the quenching stop temperature is higher than 600° C., the desired martensite or bainite structure cannot be obtained, and the γ grains produced during subsequent reheating will not be fine.
ｄ）再加熱焼入れ条件
再加熱焼入れは、細粒子からの焼入れで細粒のマルテン
サイト変態組織を得ることを狙いとしてしている。通常
、焼入れはγ域に加熱して水焼入れ或いは油焼入れする
が、そのためにはＡｃｔ点以上の温度に加熱する必要が
あり、また１０００℃を超える温度に加熱するとγ粒が
粗大化して焼入れ後に得られるマルテンサイト組織が粗
くなり、低温靭性を損なうことになる。従って、再加熱
時の温度をＡｃ、Ｊ点〜１０００℃と定めた。d) Reheating and quenching conditions Reheating and quenching aims to obtain a fine-grained martensitic transformed structure by quenching from fine particles. Usually, quenching is done by heating to the γ range and water quenching or oil quenching, but for this purpose it is necessary to heat to a temperature higher than the Act point, and if heated to a temperature exceeding 1000°C, the γ grains will become coarser and will be hardened after quenching. The resulting martensitic structure becomes rough, impairing low-temperature toughness. Therefore, the temperature at the time of reheating was set at Ac, point J to 1000°C.
ｅ）焼戻し温度
焼戻し処理は、焼入れによって導入された歪を除去し、
かつ炭化物を微細に析出させることにより強度−靭性バ
ランスを改善するために実施される。そして、この焼戻
しは一般にＡｃ、点用下の温度域で行われるのが常であ
り、この温度をに回った場合には前記バランスに支障を
来たすようになることから、本発明においても焼戻し温
度をＡｃ。e) Tempering temperature Tempering treatment removes the strain introduced by quenching,
It is also carried out to improve the strength-toughness balance by finely precipitating carbides. This tempering is generally carried out in a temperature range below Ac, and if it exceeds this temperature, the balance will be disturbed, so in the present invention, the tempering temperature is also Ac.
点用下の温度と定めた。The temperature was determined to be below the point.
続いて、本発明を実施例によって更に具体的に説明する
。Next, the present invention will be explained in more detail with reference to Examples.
〈実施例〉
まず、常法に従って第１表に示される成分組成のスラブ
を得た後、これらを第２表に示す条件で処理して厚肉鋼
板を製造した。<Example> First, slabs having the compositions shown in Table 1 were obtained according to a conventional method, and then these were treated under the conditions shown in Table 2 to produce thick steel plates.
次に、得られた各鋼板から試験片を切り出して機械的性
質の測定及び溶接性の評価を行い、その結果を第２表に
併せて示した。Next, test pieces were cut out from each of the obtained steel plates, and mechanical properties were measured and weldability evaluated. The results are also shown in Table 2.
なお、溶接性の評価はｙ開先拘束割れ試験によって行っ
たが、ｙ開先拘束割れ試験は、各鋼板より採取した斜め
ｙ開先拘束割れ試験片を１２５℃に予熱後、入熱量：
１７ ＫＪ／ｃｍで手溶接しく電流：１７０、Ａ、電圧
：２５Ｖ、速度： １５ （ＪＩｌ／ｍ１ｎ）、この際
の表面割れ、ルート割れ及び断面割れの有無を調べる条
件の下で実施した。The weldability was evaluated by a y-groove restraint cracking test, in which a diagonal y-groove restraint cracking test specimen taken from each steel plate was preheated to 125°C, and the heat input was:
Manual welding was performed at 17 KJ/cm, current: 170 A, voltage: 25 V, speed: 15 (JIl/m1n), and the presence or absence of surface cracks, root cracks, and cross-sectional cracks was examined under conditions.
第２表に示される結果からも明らかなように、本発明で
規定する条件通りに製造された）７肉鋼板は溶接割れが
認められず、かつ所望の強度（降伏強度：９０ｋｇｆ／
ｉ以上、引張強度：９７ｋｇｆ／ｍｆｆ１以−ト）及び
靭性（衝撃遷移温度ニー６０°Ｃ以下）を満足しており
、母材性能及び溶接性が共に良好な結果を示しているこ
とが分かる。As is clear from the results shown in Table 2, the 7-thick steel plate manufactured under the conditions specified in the present invention showed no weld cracking and had the desired strength (yield strength: 90 kgf/
It can be seen that both the base metal performance and weldability are satisfactory, as the specimen satisfies the requirements for tensile strength: 97 kgf/mff1 or higher) and toughness (impact transition temperature knee: 60°C or lower).
これに対して、同様成分組成鋼を用いたとしても処理方
法が本発明の規定から外れると目標性能が達成できなく
なる。On the other hand, even if steel with the same composition is used, if the treatment method deviates from the specifications of the present invention, the target performance will not be achieved.
例えば、試験番号５のように圧延後の冷却を空冷（板厚
中心部の冷却速度が３”Ｃ／ｎｉｎを超える）にすると
、再加熱焼入れの前徂織が焼入れ組織でないため再加熱
時の１粒の細粒化が図れず、再加熱焼入れによっても細
粒のマルテンサイト組織が得られないので強度を満足し
ても所望靭性が確保できない。また、試験番号６では圧
延後の冷却が空冷（板厚中心部の冷却速度が３℃／ｍｉ
ｎを超える）である上、冷却が８２５℃から行われたた
め焼入れ不足となり、所望強度そのものが得られていな
い。For example, if the cooling after rolling is air-cooled (cooling rate at the center of the sheet thickness exceeds 3"C/nin) as in Test No. 5, the front weave of the reheating and quenching is not a quenched structure, so the Since each grain cannot be made finer and a fine grained martensitic structure cannot be obtained even by reheating and quenching, the desired toughness cannot be secured even if the strength is satisfied.In addition, in test number 6, cooling after rolling was performed by air cooling. (The cooling rate at the center of the plate thickness is 3℃/mi
In addition, since cooling was performed from 825° C., quenching was insufficient, and the desired strength itself was not obtained.
更に、試験番号゛ｌでは圧延後水冷されて所定の冷却速
度の急冷がなされているが、再加熱焼入れ後の焼戻し温
度が７８０℃とＡｃ、点よりも高いので十分な強度も確
保されていない。そして、試験番号８では、９００℃以
りの圧下量が２５％と低いために圧延によるγ粒の細粒
化が図れなか、ったことに加え、圧延仕上温度が７２５
℃とＡ ｒ ３点よりも低かったために圧延途中にフェ
ライトが生じてしまって圧延後直ちに水冷を実施したに
も係わらず所望の焼入れ組織を得られず、従って再加熱
焼入れ時に１粒の細粒化が図れないで細粒のマルテンサ
イト’Ｊｌ １％が得られなかったため、強度は満足で
きても所望靭性が確保できていない。Furthermore, in test No. 1, water cooling is performed after rolling to achieve rapid cooling at a predetermined cooling rate, but sufficient strength is not ensured because the tempering temperature after reheating and quenching is 780°C, which is higher than the Ac point. . In test number 8, the rolling reduction at 900°C or higher was as low as 25%, so it was not possible to refine the γ grains by rolling, and in addition, the finishing temperature of rolling was 725°C.
Since ℃ and A r were lower than 3 points, ferrite was generated during rolling, and even though water cooling was performed immediately after rolling, the desired quenched structure could not be obtained. Therefore, during reheating quenching, one fine grain Because of the inability to obtain 1% of fine-grained martensite 'Jl, the desired toughness was not secured even though the strength was satisfied.
一方、試験番号９〜Ｉ２は素材鋼の成分組成が本発明で
規定する範囲を外れている場合の例であるが、これらの
結果からも分かるように、素材鋼の成分組成が本発明で
規定する範囲を外ね、ると所望靭性を満足できないばか
りか、所望強度の達成を主眼とした成分設計をしてＰＣ
Ｍ値を制限しなかったために溶接性の点でも満足できな
いことが分かる。On the other hand, test numbers 9 to I2 are examples in which the chemical composition of the material steel is outside the range specified by the present invention, but as can be seen from these results, the chemical composition of the material steel is outside the range specified by the present invention. If it is outside the range, not only will it not be possible to satisfy the desired toughness, but the composition will be designed with the focus on achieving the desired strength.
It can be seen that because the M value was not limited, the weldability was also unsatisfactory.
く効果の総括〉
以上に説明した如く、この発明に係る高張力１１１ｊｌ
板の製造方法によれば、降伏強度： ９０ ｋｇｆ／ｍ
ｎ１以上、引張強度：９７ｋｇｆ／−以上並びに衝撃遷
移温度ニー６０″Ｃ以下の優れた性能を有し、かつ良好
な溶接性を示ずＭ肉（例えば板厚：４Ｑｔ＋ｍ以上）高
張力Ｎ板をも安定して製造することが可能となるなど、
産業」二極めて有用な効果がもたらされる。Summary of effects> As explained above, the high tension 111jl according to the present invention
According to the manufacturing method of the plate, yield strength: 90 kgf/m
N1 or more, tensile strength: 97 kgf/- or more, and impact transition temperature knee 60''C or less, which has excellent performance, and does not show good weldability and has a high tensile strength N plate with M thickness (e.g., plate thickness: 4Qt+m or more). It is now possible to stably manufacture
``Industry'' has two extremely useful effects.
第１図Figure 1
第１図は、本発明に係る高張力Ｅ＋Ｈ製造条件の説明図
である。FIG. 1 is an explanatory diagram of high tension E+H manufacturing conditions according to the present invention.
Claims (1)
ｎ：０．４０〜１．２０％、Ｃｕ：０．５％以下、Ｎｉ
：０．４０〜３．５０％、Ｃｒ：０．１０〜１．２０％
、Ｍｏ：０．０５〜０．８％、Ｖ：０．００５〜０．１
％、Ｎｂ：０．００５〜０．０３％、ｓｏｌ．Ａｌ：０
．０１〜０．１０％、Ｂ：０．０００３〜０．００３０
％、Ｐ：０．０１％以下、Ｓ：０．００５％以下、Ｎ：
０．００４％以下で残部が実質的にＦｅから成り、かつ
式 Ｐ＿Ｃ＿Ｍ＝Ｃ（％）＋Ｓｉ（％）／３０＋Ｍｎ（％）
／２０＋Ｃｕ（％）／２０＋Ｎｉ（％）／６０＋Ｃｒ（
％）／２０＋Ｍｏ（％）／１５＋Ｖ（％）／１０＋５×
Ｂ（％） にて表わされるＰ＿Ｃ＿Ｍが０．３１％以下である鋼を
、１０００℃以上に加熱して熱間圧延し、９００℃以上
の温度域において３０％以上の累積圧下を与えると共に
８００℃以上の温度域から所定板厚に仕上圧延した後、
そのまま板厚中心部の冷却速度：３℃／ｓｅｃ以上で６
００℃以下にまで冷却し、次いでＡｃ＿３点〜９５０℃
の温度域に再加熱して水焼入れを行い、引き続いてＡｃ
＿１点以下の温度で焼戻しすることを特徴とする、靭性
に優れた調質型高張力鋼板の製造方法。[Claims] Weight percentage: C: 0.08 to 0.20%, Si: 0.30% or less, M
n: 0.40 to 1.20%, Cu: 0.5% or less, Ni
:0.40~3.50%, Cr:0.10~1.20%
, Mo: 0.05-0.8%, V: 0.005-0.1
%, Nb: 0.005-0.03%, sol. Al: 0
．． 01-0.10%, B: 0.0003-0.0030
%, P: 0.01% or less, S: 0.005% or less, N:
0.004% or less, the remainder substantially consisting of Fe, and the formula P_C_M=C(%)+Si(%)/30+Mn(%)
/20+Cu(%)/20+Ni(%)/60+Cr(
%)/20+Mo(%)/15+V(%)/10+5×
A steel whose P_C_M, expressed as B (%), is 0.31% or less is heated to 1000°C or higher and hot rolled, subjected to a cumulative reduction of 30% or more in a temperature range of 900°C or higher, and then rolled to 800°C. After finishing rolling to the specified thickness from the above temperature range,
Cooling rate at center of plate thickness: 6 at 3°C/sec or more
Cool to below 00℃, then Ac_3 points to 950℃
Water quenching is performed by reheating to a temperature range of
A method for producing a tempered high-strength steel plate with excellent toughness, characterized by tempering at a temperature of _1 point or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63287084A JPH0670249B2 (en) | 1988-11-14 | 1988-11-14 | Manufacturing method of tempered high strength steel sheet with excellent toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63287084A JPH0670249B2 (en) | 1988-11-14 | 1988-11-14 | Manufacturing method of tempered high strength steel sheet with excellent toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02133521A true JPH02133521A (en) | 1990-05-22 |
| JPH0670249B2 JPH0670249B2 (en) | 1994-09-07 |
Family
ID=17712845
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63287084A Expired - Lifetime JPH0670249B2 (en) | 1988-11-14 | 1988-11-14 | Manufacturing method of tempered high strength steel sheet with excellent toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0670249B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005256169A (en) * | 2004-02-12 | 2005-09-22 | Jfe Steel Kk | Wear resistant steel sheet having excellent low temperature toughness and production method therefor |
| WO2013051231A1 (en) * | 2011-10-03 | 2013-04-11 | Ｊｆｅスチール株式会社 | High-tensile steel plate giving welding heat-affected zone with excellent low-temperature toughness, and process for producing same |
| CN113462951A (en) * | 2021-06-29 | 2021-10-01 | 钢铁研究总院 | Preparation method of ultrahigh-strength and high-toughness alloy steel |
| CN114277222A (en) * | 2021-12-21 | 2022-04-05 | 舞阳钢铁有限责任公司 | Heat treatment method of Mn-Ni-Cr-Mo-Nb steel plate |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61127813A (en) * | 1984-11-22 | 1986-06-16 | Nippon Steel Corp | Production of high arrest refined steel containing ni |
-
1988
- 1988-11-14 JP JP63287084A patent/JPH0670249B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61127813A (en) * | 1984-11-22 | 1986-06-16 | Nippon Steel Corp | Production of high arrest refined steel containing ni |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005256169A (en) * | 2004-02-12 | 2005-09-22 | Jfe Steel Kk | Wear resistant steel sheet having excellent low temperature toughness and production method therefor |
| JP4650013B2 (en) * | 2004-02-12 | 2011-03-16 | Ｊｆｅスチール株式会社 | Abrasion resistant steel plate with excellent low temperature toughness and method for producing the same |
| WO2013051231A1 (en) * | 2011-10-03 | 2013-04-11 | Ｊｆｅスチール株式会社 | High-tensile steel plate giving welding heat-affected zone with excellent low-temperature toughness, and process for producing same |
| JP2013091845A (en) * | 2011-10-03 | 2013-05-16 | Jfe Steel Corp | High-tensile steel plate giving welding heat-affected zone with excellent low-temperature toughness, and method for producing the same |
| JPWO2013051231A1 (en) * | 2011-10-03 | 2015-03-30 | Ｊｆｅスチール株式会社 | High tensile strength steel sheet with excellent low temperature toughness of weld heat affected zone and method for producing the same |
| US9945015B2 (en) | 2011-10-03 | 2018-04-17 | Jfe Steel Corporation | High-tensile steel plate giving welding heat-affected zone with excellent low-temperature toughness, and process for producing same |
| CN113462951A (en) * | 2021-06-29 | 2021-10-01 | 钢铁研究总院 | Preparation method of ultrahigh-strength and high-toughness alloy steel |
| CN114277222A (en) * | 2021-12-21 | 2022-04-05 | 舞阳钢铁有限责任公司 | Heat treatment method of Mn-Ni-Cr-Mo-Nb steel plate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0670249B2 (en) | 1994-09-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20080295920A1 (en) | High Tension Steel Plate with Small Acoustic Anisotropy and with Excellent Weldability and Method of Production of Same | |
| KR20000069212A (en) | Thermomechanically controlled processed high strength weathering steel with low yield/tensile ratio | |
| CN111621716B (en) | Nb-containing low alloy steel rolling process | |
| CN112877591A (en) | High-strength and high-toughness steel for hardware tool and chain and manufacturing method thereof | |
| CN105063511B (en) | Ultra-low carbon bainite thin gauge steel plate rolled through heavy and medium plate mill and production method of ultra-low carbon bainite thin gauge steel plate | |
| CN109943771B (en) | High-toughness weldable steel plate with fine grain structure and production method thereof | |
| JPS5983719A (en) | Preparation of unnormalized high strength steel | |
| JPH04285119A (en) | Production of thick-walled high tensile strength steel plate excellent in toughness at low temperature | |
| JPS63286517A (en) | Manufacture of high-tensile steel with low yielding ratio | |
| JP5266804B2 (en) | Method for producing rolled non-heat treated steel | |
| JP3873540B2 (en) | Manufacturing method of high productivity and high strength rolled H-section steel | |
| JP3602471B2 (en) | High tensile strength steel sheet excellent in weldability and method for producing the same | |
| JP3499705B2 (en) | 950N / mm2 class tempered high-strength steel sheet having excellent homogeneity in thickness direction and low anisotropy of toughness, and method for producing the same | |
| JPH02133521A (en) | Production of tempered high tensile steel plate having excellent toughness | |
| JPS6156235A (en) | Manufacture of high toughness nontemper steel | |
| JPS63183123A (en) | Production of high tensile steel having excellent low-temperature toughness after linear and spotty reheating | |
| JP3327065B2 (en) | Method for producing tempered high-strength steel sheet excellent in brittle crack propagation arrestability | |
| JPH04110422A (en) | Production of 70kgf/mm2 class steel plate having superior weldability and low yield ratio | |
| JPH02141528A (en) | Manufacture of tempered-type high tensile steel plate excellent in toughness | |
| JPS6358906B2 (en) | ||
| JPH05148544A (en) | Production of high-strength high-toughness steel plate having uniform hardness distribution in thickness direction | |
| JPH01195242A (en) | Manufacture of high tension steel plate having superior toughness at low temperature with uniformity in thickness direction | |
| JPH0445227A (en) | Production of steel product with low yield ratio | |
| JPS6338518A (en) | Production of steel plate having excellent hydrogen induced cracking resistance | |
| JPH04110423A (en) | Production of 80kgf/mm2 class steel plate having superior weldability and low yield ratio |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080907 Year of fee payment: 14 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080907 Year of fee payment: 14 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090907 Year of fee payment: 15 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090907 Year of fee payment: 15 |