JPS6115929B2 - - Google Patents
Info
- Publication number
- JPS6115929B2 JPS6115929B2 JP55041398A JP4139880A JPS6115929B2 JP S6115929 B2 JPS6115929 B2 JP S6115929B2 JP 55041398 A JP55041398 A JP 55041398A JP 4139880 A JP4139880 A JP 4139880A JP S6115929 B2 JPS6115929 B2 JP S6115929B2
- Authority
- JP
- Japan
- Prior art keywords
- ductility
- strength
- balance
- steel
- rolled steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 43
- 239000010959 steel Substances 0.000 claims description 43
- 238000001816 cooling Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 238000005096 rolling process Methods 0.000 claims description 8
- 239000012535 impurity Substances 0.000 claims description 4
- 238000005098 hot rolling Methods 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims 4
- 238000000034 method Methods 0.000 description 25
- 238000005728 strengthening Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229910052758 niobium Inorganic materials 0.000 description 5
- 229910052720 vanadium Inorganic materials 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 229910000655 Killed steel Inorganic materials 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910001327 Rimmed steel Inorganic materials 0.000 description 1
- 229910001336 Semi-killed steel Inorganic materials 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000005486 sulfidation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Description
本発明は強度−延性バランスの優れた熱間圧延
鋼板の製造方法に関する。
一般に、鋼材は降伏点および引張強さ等の強度
が上昇するに従つて全伸び、切欠伸びおよび曲げ
等の延性が劣化するのが普通であることはよく知
られている。
しかしながら、鋼材において強度と延性との相
関関係（以下強度−延性バランスという。）は、
可成り広いバンドを示すのが通常である。即ち、
同一強度の鋼材でもその延性の幅は相当広いもの
であり、これは、強度の他にも延性を支配する要
因があることを意味している。そして、これらの
要因の主なものとしては介在物、組織、結晶粒度
また析出物等がある。
従つて熱間圧延鋼板において、強度−延性バラ
ンスを向上させる方法として、例えば、介在物特
に圧延方向に延伸した硫化物系または珪酸塩系介
在物を少なくする方法、組織成分として延性に有
害なパーライトがベンナイトを少なくする方法、
および、結晶粒微細化による強化方法や固溶強化
方法のように強化の割りには延性低下の少ない鋼
の強化方法等の各種方法が個別に或いは適宜組合
せて用いられている。また、これらの方法を実施
するための種々の具体的手段が提案されている。
しかしながら、これら従来の方法では、熱間圧
延鋼材の強度−延性バランスの優れたものを得る
には末だ充分満足するには至つていないのが実情
である。
本発明は上記した点に鑑みなされたものであつ
て、強度−延性の優れた熱間圧延鋼材を比較的容
易に製造することができるものであり、その特徴
とするところは、(1)Ｃ 0.03〜0.20％、Si 1.0％
以下、Mn 0.3〜1.8％を含有し残部Fe及び不純物
よりなる鋼を熱間圧延した後、仕上げ後の冷却速
度15〜40℃／sec、巻取温度を550℃以下とするこ
とを特徴とする強度−延性バランスの優れた熱間
圧延鋼板の製造方法を第１の発明とし、(2) Ｃ
0.03〜0.2％、Si 1.0％以下、Mn 0.3〜1.8％を含
有し、且つ、Nb 0.005〜0.10％、Ｖ 0.005〜
0.10％の少くとも一種を含有し、残部Fe及び不
純物よりなる鋼を熱間圧延した後、仕上げ後の冷
却速度15〜40℃／sec、巻取温度を550℃以下とす
ることを特徴とする強度−延性バランスの優れた
熱間圧延鋼板の製造方法を第２の発明とする２つ
の発明よりなるものである。
本発明に係る強度−延性バランスの優れた熱間
圧延鋼板の製造方法（以下単に本発明に係る方法
ということもある。）について詳細に説明する。
先づ、本発明に係る方法において使用される鋼
の含有成分と含有割合について説明する。
Ｃは熱間圧延鋼板の強度と加工性に影響を与え
る含有成分であり、その含有量が0.03％未満では
強度を上昇させる効果が少なく、また、0.20％を
越えて含有されると加工性が劣るようになる。よ
つて、Ｃ含有量は0.03〜0.20％の範囲とするのが
好ましい。
Siは固溶強化元素であり、このSi含有による強
化は延性低下が少ないので加工用の熱間圧延鋼板
には好ましい含有元素であるが、多量に含有され
ていると鋼板の表面性状が劣化し、また、溶接性
を損なうようになる。よつて、Si含有量は1.0％
と以下とするのである。
Mnは強度、加工性、溶接性に影響を及ぼす含
有成分であり、その含有量が0.03％未満では熱間
脆性防止の効果がなく、また、1.80％を越えて含
有されると加工性、溶接性が著しく劣化するので
ある。よつてMn含有量は0.03〜1.80％の範囲と
する。
本発明に係る方法において使用される鋼には、
上記各成分以外にNb0.005〜0.1％、Ｖ 0.005〜
0.1％の少なくとも一種が含有されている場合が
あり、このNb、または、Ｖは析出強化元素であ
つて、仕上圧延後の急冷によつて析出物が微細に
析出するので合金元素の効果を最大限に発揮させ
るのに有効であり、さらに、析出物が微細である
ために延性低下の度合が少ないのである。
しかし、このNbまたはＶの析出強化元素は、
その含有量が0.005％未満ではその効果が期待す
ることができず、また、0.1％を越えて含有され
ると好ましくない組織を呈する場合が多くなる。
よつて、Nb，Ｖはその含有量を0.005〜0.1％の範
囲とするのである。
本発明に係る方法においては、特定の含有成分
および含有割合の鋼、例えば、分塊スラブ、また
は、連続鋳造スラブ等を使用して、粗圧延、仕上
圧延を行なつた後、ラミナー、または、スプレー
水で冷却し、冷却後所定の温度で巻取る熱間圧延
鋼板の製造工程中の、仕上後巻取りまでの鋼板の
平均冷却速度15〜40℃／sec、かつ、巻取温度を
550℃以下とすることが必要である。
これは、仕上圧延後の冷却速度を高めることに
よつて、フエライト粒の微細化をはかり、同一含
有成分の鋼であるならば延性低下を僅少にして強
度上昇をはかり、かつ、巻取温度を低くすること
によつて巻取後にその微細フエライト粒を粗大化
させず、また、延性には有害な粗大パーライトの
析出を抑制するための手段であつて、治金学的に
も極めて合理的なものである。
なお、40℃／se以上の冷却速度は不要であると
同時に延性劣化の原因となるベイナイト等が増大
するので好ましくない。
そして、鋼板の製造条件、例えば、鋼片加熱温
度、粗圧延条件、仕上圧延条件は適正な範囲に規
定する必要はあるが、通常の鋼板の製造条件が適
用された熱間圧延鋼板であればそのすべてに本発
明に係る方法を適用することが可能である。
なお、本発明に係る方法を適用することができ
る鋼種としそは、リムド鋼、セミキルド鋼、キル
ド鋼の何れも使用することができ、また、造塊、
連続鋳造材の如何は問わない。従つてＡは必須
成分ではないが、Ａキルド鋼に通常含有される
程量の量は許容される。
以下、本発明に係る強度−延性バランスの優れ
た熱間圧延鋼板の製造方法の実施例について説明
する。
実施例
第１表に示す各種鋼について、通常の溶製によ
り含有成分、成分割合となるように製造した。そ
して、第１表に示す冷却条件および巻取温度条件
により熱間圧延鋼板を製造した。
第１表に機械的性質として、引張強さ、全伸び
および切欠伸びを示してある。
第１表において、鋼の３，５，８，９，13，
17，21，25は本発明に係る方法により得られた熱
間圧延鋼板で、他の番号は比較鋼である。なお、
以下説明する第１図および第２図においても第１
表と同様である。
The present invention relates to a method for producing a hot rolled steel sheet with an excellent balance of strength and ductility. It is generally well known that as the strength of steel materials, such as yield point and tensile strength, increases, the ductility, such as total elongation, notch elongation, and bending, generally deteriorates. However, the correlation between strength and ductility (hereinafter referred to as strength-ductility balance) in steel materials is
It usually shows a fairly broad band. That is,
Even steel materials with the same strength have a considerably wide range of ductility, which means that there are factors other than strength that govern ductility. The main factors include inclusions, structure, grain size, and precipitates. Therefore, methods for improving the strength-ductility balance in hot-rolled steel sheets include, for example, methods for reducing inclusions, particularly sulfide-based or silicate-based inclusions stretched in the rolling direction, and methods for reducing pearlite, which is harmful to ductility as a structural component. How to reduce Bennite,
In addition, various methods are used individually or in appropriate combinations, such as methods for strengthening steel by grain refinement and solid solution strengthening methods, which cause less reduction in ductility compared to strengthening. Furthermore, various specific means for implementing these methods have been proposed. However, the reality is that these conventional methods are far from satisfactory in obtaining hot rolled steel products with an excellent strength-ductility balance. The present invention has been made in view of the above points, and enables relatively easy production of hot rolled steel materials with excellent strength and ductility.The present invention is characterized by: (1) C 0.03~0.20%, Si 1.0%
Hereinafter, after hot rolling a steel containing 0.3 to 1.8% Mn and the remainder Fe and impurities, the cooling rate after finishing is 15 to 40°C/sec, and the coiling temperature is 550°C or less. The first invention is a method for producing a hot rolled steel sheet with an excellent strength-ductility balance, and (2) C
Contains 0.03 to 0.2%, Si 1.0% or less, Mn 0.3 to 1.8%, and Nb 0.005 to 0.10%, V 0.005 to
After hot-rolling a steel containing 0.10% of at least one kind, with the balance consisting of Fe and impurities, the cooling rate after finishing is 15 to 40°C/sec, and the coiling temperature is 550°C or less. This invention consists of two inventions, the second invention being a method for manufacturing a hot rolled steel sheet with an excellent balance of strength and ductility. The method for manufacturing a hot rolled steel plate with an excellent strength-ductility balance according to the present invention (hereinafter also simply referred to as the method according to the present invention) will be explained in detail. First, the components and content ratios of the steel used in the method according to the present invention will be explained. C is a component that affects the strength and workability of hot-rolled steel sheets. If its content is less than 0.03%, it has little effect on increasing the strength, and if it is contained in more than 0.20%, the workability is reduced. become inferior. Therefore, the C content is preferably in the range of 0.03 to 0.20%. Si is a solid solution strengthening element, and strengthening due to the inclusion of Si causes little decrease in ductility, so it is a preferable element for hot rolled steel sheets for processing, but if it is contained in large amounts, the surface quality of the steel sheet deteriorates. , it also impairs weldability. Therefore, the Si content is 1.0%
and the following. Mn is a component that affects strength, workability, and weldability. If its content is less than 0.03%, it has no effect on preventing hot embrittlement, and if it exceeds 1.80%, it affects workability and weldability. This results in a significant deterioration in performance. Therefore, the Mn content should be in the range of 0.03 to 1.80%. The steel used in the method according to the invention includes:
In addition to the above components, Nb0.005~0.1%, V0.005~
Nb or V may contain 0.1% of at least one kind of element, and this Nb or V is a precipitation-strengthening element, and the precipitates are finely precipitated by rapid cooling after finish rolling, so the effect of the alloying element is maximized. It is effective in achieving maximum performance, and furthermore, since the precipitates are fine, the degree of deterioration in ductility is small. However, this precipitation strengthening element of Nb or V
If the content is less than 0.005%, no effect can be expected, and if the content exceeds 0.1%, an undesirable structure will often be exhibited.
Therefore, the content of Nb and V is set in the range of 0.005 to 0.1%. In the method according to the present invention, after rough rolling and finish rolling are performed using steel having a specific content and content ratio, such as a blooming slab or a continuous casting slab, laminar or During the manufacturing process of hot-rolled steel sheets, which are cooled with spray water and rolled at a predetermined temperature after cooling, the average cooling rate of the steel sheet after finishing and winding is 15 to 40℃/sec, and the winding temperature is
It is necessary to keep the temperature below 550℃. This aims to refine the ferrite grains by increasing the cooling rate after finish rolling, and if the steel contains the same ingredients, it increases the strength with a slight decrease in ductility, and the coiling temperature can be reduced. It is a means to prevent the fine ferrite grains from becoming coarse after winding by lowering the temperature, and to suppress the precipitation of coarse pearlite that is harmful to ductility. It is something. Note that a cooling rate of 40° C./se or higher is unnecessary and at the same time undesirable because it increases bainite, etc., which causes ductility deterioration. Although it is necessary to specify the manufacturing conditions for steel plates, such as billet heating temperature, rough rolling conditions, and finish rolling conditions within appropriate ranges, if the hot rolled steel plate is manufactured under normal steel plate manufacturing conditions, then It is possible to apply the method according to the present invention to all of them. The steel type to which the method according to the present invention can be applied may be rimmed steel, semi-killed steel, or killed steel.
It does not matter what type of continuous casting material it is. Therefore, although A is not an essential component, it is permissible in an amount that is normally contained in A-killed steel. Examples of the method for manufacturing a hot rolled steel sheet with excellent strength-ductility balance according to the present invention will be described below. Examples Various types of steel shown in Table 1 were produced by normal melting so that the contained components and component ratios were the same. Then, hot rolled steel plates were manufactured under the cooling conditions and coiling temperature conditions shown in Table 1. Table 1 shows tensile strength, total elongation, and notch elongation as mechanical properties. In Table 1, steel 3, 5, 8, 9, 13,
17, 21, and 25 are hot rolled steel sheets obtained by the method according to the present invention, and the other numbers are comparative steels. In addition,
Also in Figures 1 and 2, which will be explained below,
Same as table.
【表】【table】
【表】
この第１表からも明らかであるが、本発明に係
る方法により得られた鋼板３，５，８，９，１
３，１７，２１，２５は、引張強さは他の鋼板に
比較して高い割には全伸びと切欠伸びは略同等で
ある。これからみても、強度−延性バランスは本
発明に係る方法により得られた熱間圧延鋼板の方
が優れていることがわかる。
また、第１図は強度（引張強さ５−延性（全伸
び）バランスを示したものであり、冷却速度が15
℃／sec以上（本発明に係る方法）のものが良好
な強度−全伸びバランスを示している（鋼：３，
５，８，９，13，17，21，25）ことがわかる。
第２図は強度（引張強さ）−延性（切欠伸び）
バランスを示したものであり、巻取り温度が550
℃以下（本発明に係る方法）のものが良好な強度
−切欠伸びバランスを示している（鋼３，５，
８，９，13，17，21，25）ことがわかる。
そして、第１表、および、第１図、第２図の説
明から、仕上後の冷却速度を15℃／sec以上と
し、また巻取温度を550℃以下としなければ優れ
た強度−延性バランスを有する熱間圧延鋼板を得
ることができないことは明らかである。
以上、説明したように、本発明に係る強度−延
性バランスの優れた熱間圧延鋼板の製造方方法は
上記の構成を有しているものであるから、従来の
方法に比して合金元素の含有量の少ない鋼を使用
することができ、かつ、例えば、低硫化、或い
は、硫化物形状制御を本発明に係る方法に適用し
てより効果を大きくすることもできるという効果
がある。[Table] As is clear from Table 1, steel plates 3, 5, 8, 9, 1 obtained by the method according to the present invention
Although the tensile strength of Nos. 3, 17, 21, and 25 is higher than that of other steel sheets, the total elongation and notch elongation are approximately the same. This also shows that the hot rolled steel sheet obtained by the method according to the present invention has a better strength-ductility balance. In addition, Figure 1 shows the strength (tensile strength 5 - ductility (total elongation) balance), and the cooling rate is 15
℃/sec or more (method according to the present invention) shows a good strength-total elongation balance (steel: 3,
5, 8, 9, 13, 17, 21, 25). Figure 2 shows strength (tensile strength) - ductility (notch elongation)
This shows the balance, and the winding temperature is 550
℃ or less (method according to the present invention) shows a good strength-notch elongation balance (steels 3, 5,
8, 9, 13, 17, 21, 25). From the explanations in Table 1 and Figures 1 and 2, it is clear that an excellent strength-ductility balance can be achieved only when the cooling rate after finishing is 15°C/sec or higher and the coiling temperature is 550°C or lower. It is clear that it is not possible to obtain a hot rolled steel plate with. As explained above, since the method for manufacturing a hot rolled steel sheet with an excellent strength-ductility balance according to the present invention has the above-mentioned structure, the amount of alloying elements is reduced compared to the conventional method. There is an advantage that steel with a small content can be used and, for example, low sulfidation or sulfide shape control can be applied to the method according to the present invention to further increase the effect.
第１図は強度−全伸びバランスを本発明に係る
方法と従来法とを比較して示した説明図、第２図
は強度−切欠伸びバランスを本発明に係る方法と
従来法とを比較して示した説明図である。
Fig. 1 is an explanatory diagram showing a comparison of the strength-total elongation balance between the method according to the present invention and the conventional method, and Fig. 2 shows a comparison of the strength-notch elongation balance between the method according to the present invention and the conventional method. FIG.
Claims (1)
延した後、仕上げ後の冷却速度を15〜40℃／
sec、巻取温度を550℃以下とすることを特徴とす
る強度−延性バランスの優れた熱間圧延鋼板の製
造方法。 ２ Ｃ 0.03〜0.20％、Si 1.0％以下、 Mn 0.3〜1.8％ を含有し、且つ、 Nb 0.005〜0.10％、Ｖ 0.005〜0.10％ の少なくとも一方 を含有し、残部鉄及び不純物よりなる鋼を熱間圧
延した後、仕上げ後の冷却速度を15〜40℃／se、
巻取温度550℃以下とすることを特徴とする強度
−延性バランスの優れた熱間圧延鋼板の製造方
法。[Claims] 1. After hot rolling a steel containing 0.03 to 0.20% C, 1.0% or less Si, and 0.3 to 1.8% Mn, with the balance consisting of iron and impurities, the cooling rate after finishing is reduced to 15%. ~40℃/
sec, a coiling temperature of 550°C or less, a method for producing a hot rolled steel sheet with an excellent strength-ductility balance. 2 A steel containing 0.03 to 0.20% of C, 1.0% or less of Si, 0.3 to 1.8% of Mn, and at least one of 0.005 to 0.10% of Nb and 0.005 to 0.10% of V, with the balance consisting of iron and impurities is heated. After rolling, the cooling rate after finishing is set at 15 to 40℃/se,
1. A method for producing a hot rolled steel sheet with an excellent strength-ductility balance, characterized in that the coiling temperature is 550°C or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4139880A JPS56139626A (en) | 1980-03-31 | 1980-03-31 | Production of hot-rolled steel plate of superior strength-ductility balance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4139880A JPS56139626A (en) | 1980-03-31 | 1980-03-31 | Production of hot-rolled steel plate of superior strength-ductility balance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56139626A JPS56139626A (en) | 1981-10-31 |
| JPS6115929B2 true JPS6115929B2 (en) | 1986-04-26 |
Family
ID=12607270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4139880A Granted JPS56139626A (en) | 1980-03-31 | 1980-03-31 | Production of hot-rolled steel plate of superior strength-ductility balance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56139626A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6818079B2 (en) | 1999-09-19 | 2004-11-16 | Nkk Corporation | Method for manufacturing a steel sheet |
| EP2166122A1 (en) | 1999-09-16 | 2010-03-24 | JFE Steel Corporation | Method of manufacturing high strength steel |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5855528A (en) * | 1981-09-29 | 1983-04-01 | Kawasaki Steel Corp | Preparation of hot-rolled steel sheet having excellent acid-pickling property and workability |
| JPS62136529A (en) * | 1985-12-09 | 1987-06-19 | Kawasaki Steel Corp | Production of tight scale steel sheet |
| KR100482201B1 (en) * | 2002-10-18 | 2005-04-14 | 주식회사 포스코 | Method for hot rolled steel sheet having excellent coiling quality for line pipe |
| KR20040041890A (en) * | 2002-11-12 | 2004-05-20 | 현대자동차주식회사 | Fuel filler door locking apparatus of automobile |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4914610A (en) * | 1972-06-02 | 1974-02-08 | ||
| JPS5114817A (en) * | 1974-07-30 | 1976-02-05 | Nippon Steel Corp | PURESUYOKOKYODONETSUENKOHANNO SEIZOHOHO |
| JPS5379716A (en) * | 1976-12-24 | 1978-07-14 | Nippon Steel Corp | Manufacture of hot rolled steel for warm working |
| JPS5395121A (en) * | 1977-02-01 | 1978-08-19 | Nippon Kokan Kk <Nkk> | Preparation of high tensile steel sheet |
| JPS5528336A (en) * | 1978-08-18 | 1980-02-28 | Nippon Steel Corp | Manufacture of hot rolled precipitation hardening type steel sheet of low yield ratio of 0.8 or less |
-
1980
- 1980-03-31 JP JP4139880A patent/JPS56139626A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4914610A (en) * | 1972-06-02 | 1974-02-08 | ||
| JPS5114817A (en) * | 1974-07-30 | 1976-02-05 | Nippon Steel Corp | PURESUYOKOKYODONETSUENKOHANNO SEIZOHOHO |
| JPS5379716A (en) * | 1976-12-24 | 1978-07-14 | Nippon Steel Corp | Manufacture of hot rolled steel for warm working |
| JPS5395121A (en) * | 1977-02-01 | 1978-08-19 | Nippon Kokan Kk <Nkk> | Preparation of high tensile steel sheet |
| JPS5528336A (en) * | 1978-08-18 | 1980-02-28 | Nippon Steel Corp | Manufacture of hot rolled precipitation hardening type steel sheet of low yield ratio of 0.8 or less |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2166122A1 (en) | 1999-09-16 | 2010-03-24 | JFE Steel Corporation | Method of manufacturing high strength steel |
| EP2166121A1 (en) | 1999-09-16 | 2010-03-24 | JFE Steel Corporation | High strength steel sheet and method for manufacturing the same |
| US6818079B2 (en) | 1999-09-19 | 2004-11-16 | Nkk Corporation | Method for manufacturing a steel sheet |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56139626A (en) | 1981-10-31 |
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