JPH0747769B2 - Manufacturing method of thick steel plate with little material difference in thickness direction - Google Patents
Manufacturing method of thick steel plate with little material difference in thickness directionInfo
- Publication number
- JPH0747769B2 JPH0747769B2 JP61166456A JP16645686A JPH0747769B2 JP H0747769 B2 JPH0747769 B2 JP H0747769B2 JP 61166456 A JP61166456 A JP 61166456A JP 16645686 A JP16645686 A JP 16645686A JP H0747769 B2 JPH0747769 B2 JP H0747769B2
- Authority
- JP
- Japan
- Prior art keywords
- thick steel
- thickness direction
- steel plate
- cooling
- plate thickness
- 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 - Fee Related
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 30
- 239000010959 steel Substances 0.000 title claims description 30
- 239000000463 material Substances 0.000 title claims description 22
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 238000001816 cooling Methods 0.000 claims description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 238000005098 hot rolling Methods 0.000 claims description 5
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 description 15
- 238000007796 conventional method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000009466 transformation Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
Landscapes
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は板厚方向の材質差の少ない厚鋼板の製造法に関
し、さらに詳しくは、高靱性、高張力鋼の板厚方向の材
質差の少ない厚鋼板の製造法に関する。TECHNICAL FIELD The present invention relates to a method for manufacturing a thick steel plate having a small material difference in the plate thickness direction, and more specifically, a method for producing a material having a high toughness and a high tensile strength in the plate thickness direction. The present invention relates to a method for manufacturing a small number of thick steel plates.
［従来技術］ 近年、鋼構造物が大型化するのに加えて、施工、使用環
境も過酷化してきており、より厚肉で溶接性に優れ、か
つ、高靱性、高張力厚鋼板が要求されてきている。[Prior Art] In recent years, in addition to the increase in the size of steel structures, the construction and use environments have also become more severe, and there is a demand for thicker, better weldability, high toughness, and high tensile thick steel plates. Is coming.
そして、従来の焼きならし・制御圧延では性能、製造可
能板厚に限界があり、また、焼入れ、焼戻し法はコスト
高になるという問題があり、このような問題を解決する
方法として、最近加速冷却法が行なわれるようになって
きている。The conventional normalizing / controlled rolling has limitations in performance and manufacturable sheet thickness, and quenching and tempering methods have the problem of high cost. Cooling methods are becoming popular.
しかし、熱間圧延後の厚鋼板を加速冷却する際に、板厚
40mm以上の場合には冷却水量を一定とする注水量では、
板厚方向の材質差が大きくなるという問題があった。However, when accelerating cooling the thick steel plate after hot rolling,
In the case of 40 mm or more, the amount of cooling water to be kept constant is
There is a problem that the material difference in the plate thickness direction becomes large.
［発明が解決しようとする問題点］ 本発明は上記に説明したように従来における熱間圧延後
の厚鋼板の加速冷却法の問題点に鑑み、本発明者が鋭意
研究を行い、検討を重ねた結果、板厚方向の材質差の少
ない高靱性、高張力厚鋼板の製造法を開発したのであ
る。[Problems to be Solved by the Invention] In view of the problems of the conventional accelerated cooling method for thick steel plates after hot rolling as described above, the present invention has been earnestly studied by the present inventor and repeatedly studied. As a result, we have developed a method of manufacturing high-toughness, high-strength steel plates with little material difference in the plate thickness direction.
［問題点を解決するための手段］ 本発明に係る板厚方向の材質差の少ない厚鋼板の製造法
の特徴とするところは、熱間圧延後の厚鋼板を加速冷却
するに際し、0.05〜0.50m3/min・m2の水量密度で冷却を
開始し、その後0.30〜1.50m3/min・m2の水量密度になる
まで徐々に注水量を増加することにある。[Means for Solving Problems] A feature of the method for producing a thick steel sheet with a small material difference in the sheet thickness direction according to the present invention is that when the thick steel sheet after hot rolling is accelerated and cooled, it is 0.05 to 0.50. Cooling is started at a water density of m 3 / min · m 2 , and then the water injection amount is gradually increased until the water density reaches 0.30 to 1.50 m 3 / min · m 2 .
本発明に係る板厚方向の材質差の少ない厚鋼板の製造法
について以下詳細に説明する。A method of manufacturing a thick steel plate having a small material difference in the plate thickness direction according to the present invention will be described in detail below.
一般に、熱間圧延後の厚鋼板を加速冷却する場合、Ar3
変態点通過時の冷却速度により厚鋼板の強靱化の度合が
異なる。そして、従来の加速冷却では水量密度を一定に
するのが一般的であったため、厚鋼板の表面と内部にお
けるAr3変態点通過時の冷却速度が異なり、その結果板
厚方向の材質差が大きくなっていた。Generally, when accelerating cooling a thick steel plate after hot rolling, Ar 3
The degree of toughening of thick steel plates varies depending on the cooling rate when passing through the transformation point. And, in the conventional accelerated cooling, it was general to keep the water amount density constant, so the cooling rate at the time of passing the Ar 3 transformation point on the surface and inside of the thick steel plate was different, and as a result, the material difference in the plate thickness direction was large. Was becoming.
しかして、本発明に係る板厚方向の材質差の少ない厚鋼
板の製造法においては、加速冷却する際に、水量密度を
0.05〜0.50m3/min・m2として冷却を開始し、その後、水
量密度を0.30〜1.50m3/min・m2になるまで徐々に注水量
を増加して、厚鋼板の表面と内部におけるAr3変態点通
過時の冷却速度差を小さくすることにより、板厚方向の
材質差を少なくすることができる。Therefore, in the method for manufacturing a thick steel plate with a small material difference in the plate thickness direction according to the present invention, when performing accelerated cooling,
Start cooling as 0.05~0.50m 3 / min · m 2, then increased gradually water injection amount until the water density in 0.30~1.50m 3 / min · m 2, the surface and the inside of the steel plate By reducing the cooling rate difference when passing the Ar 3 transformation point, it is possible to reduce the material difference in the plate thickness direction.
そして、冷却開始時の水量密度は、0.05m3/min・m2未満
では冷却による強靱化効果がなく、また、0.50m3/min・m
2を越えると表面の冷却速度が速くなりすぎて、後で水
量密度を大きくしても内部の冷却速度上昇には限界があ
り、板厚方向の材質差が大きくなる。よって、冷却開始
時の水量密度は0.05〜0.50m3/min・m2とする。When the water amount density at the start of cooling is less than 0.05 m 3 / min ・ m 2 , there is no toughening effect due to cooling, and 0.50 m 3 / min ・ m
If it exceeds 2 , the cooling rate of the surface becomes too fast, and even if the water amount density is increased later, there is a limit to the increase of the internal cooling rate, and the material difference in the plate thickness direction becomes large. Therefore, the water density at the start of cooling is 0.05 to 0.50 m 3 / min · m 2 .
また、冷却終了時の水量密度は0.30m3/min・m2未満では
内部の強靱化効果が少なく、1.50m3/min・m2を越えると
熱伝達係数が上昇しなくなる。よって、冷却終了時の水
量密度は0.30〜1.50m3/min・m2とする。When the water amount density at the end of cooling is less than 0.30 m 3 / min · m 2 , the internal toughening effect is small, and when it exceeds 1.50 m 3 / min · m 2 , the heat transfer coefficient does not rise. Therefore, the water density at the end of cooling is 0.30 to 1.50 m 3 / min · m 2 .
次ぎに、本発明に係る板厚方向の材質差の少ない厚鋼板
の製造法（本発明法ということがある。）について従来
法と比較しながら図により説明する。Next, a method of manufacturing a thick steel plate having a small material difference in the plate thickness direction according to the present invention (sometimes referred to as the present invention method) will be described with reference to the drawings in comparison with a conventional method.
第１図は本発明法１および従来法２の加速冷却を行った
場合の水量密度の変化と厚鋼板の表面・内部の温度変化
を示したものであり、Ar3変態点通過時の冷却速度が従
来法２では表面と内部で大きく異なるのに対し、本発明
法１ではほぼ等しくなっている。FIG. 1 shows changes in the water amount density and changes in the temperature of the surface and inside of the thick steel plate when the accelerated cooling of the present invention method 1 and the conventional method 2 was performed, and the cooling rate when passing the Ar 3 transformation point. However, in the conventional method 2, the surface and the inside are largely different from each other, but in the method 1 of the present invention, they are almost equal.
第２図は焼ならし３と本発明法１および従来法２の加速
冷却を行った場合の、厚鋼板の板厚方向の硬度差を板厚
別に示したものであり、水量密度一定の従来法２の加速
冷却法では板厚方向の硬度差は板厚の増加と共に大きく
なっているのに対し、本発明法１のように水量密度を徐
々に増加させる方法では板厚が増加しても板厚方向の硬
度差は焼ならし材に近い値を示しており、特に板厚40mm
以上で本発明法１の場合は板厚方向の材質均一化効果は
顕著である。FIG. 2 shows hardness differences in the plate thickness direction of thick steel plates for each plate thickness when normalizing 3 and accelerated cooling according to the present invention method 1 and the conventional method 2 are performed. In the accelerated cooling method of Method 2, the difference in hardness in the plate thickness direction increases as the plate thickness increases, whereas in the method of the present invention method 1 in which the water amount density is gradually increased, the plate thickness increases. The hardness difference in the plate thickness direction is close to that of the normalized material, especially the plate thickness of 40 mm.
As described above, in the case of the method 1 of the present invention, the effect of uniformizing the material in the plate thickness direction is remarkable.
［実施例］ 本発明に係る板厚方向の材質差の少ない厚鋼板の製造法
の実施例を説明する。[Example] An example of a method for manufacturing a thick steel plate according to the present invention with a small material difference in the plate thickness direction will be described.
実施例 第１表に示す含有成分および含有割合の材料を用い、焼
ならしと本発明法および従来法の加速冷却法により製造
した厚鋼板の板厚方向の硬度分布の比較を第３図に示
す。Example FIG. 3 shows a comparison of hardness distributions in the plate thickness direction of thick steel plates produced by normalizing and the accelerated cooling method of the present invention and the conventional method using the materials having the content components and content ratios shown in Table 1. Show.
本発明法１の加速冷却法の場合は、焼ならし３に近い板
厚方向の材質の均一性を示している。In the case of the accelerated cooling method of the method 1 of the present invention, the uniformity of the material in the plate thickness direction, which is close to that of the normalization 3, is shown.
第２表にこれらの厚鋼板の機械的性質を示す。Table 2 shows the mechanical properties of these thick steel plates.
この第２表から、本発明法による加速冷却法では、板厚
方向の材質の均一性を損なうことなく、厚鋼板の強靱化
を達成することができることがわかる。It can be seen from Table 2 that the accelerated cooling method according to the present invention can achieve the toughening of thick steel plates without impairing the uniformity of the material in the plate thickness direction.
［発明の効果］ 以上説明したように、本発明に係る板厚方向の材質差の
厚鋼板の製造法は上記の構成であるから、加速冷却に際
し、徐々に水量密度を増加させるような注水条件とした
ので焼きならし材とほぼ同等の板厚方向の材質の均一性
を有する高靱性、高張力厚鋼板を効率よく製造すること
ができるという効果がある。 [Effects of the Invention] As described above, since the method for manufacturing a thick steel plate having a material difference in the plate thickness direction according to the present invention has the above-described configuration, the water injection condition that gradually increases the water amount density during accelerated cooling. Therefore, there is an effect that it is possible to efficiently manufacture a high-toughness, high-tensile thick steel plate having a material uniformity in the plate thickness direction which is almost equal to that of the normalizing material.
第１図は加速冷却における水量密度の変化と厚鋼板の温
度変化を示す図、第２図は加速冷却により得られた厚鋼
板の表面と内部の硬度差を示す図、第３図は加速冷却に
より得られた厚鋼板の板厚方向の硬度分布を示す図であ
る。FIG. 1 is a diagram showing a change in water amount density and temperature change of a thick steel plate in accelerated cooling, FIG. 2 is a diagram showing a hardness difference between a surface and an inside of the thick steel plate obtained by the accelerated cooling, and FIG. 3 is an accelerated cooling. It is a figure which shows the hardness distribution of the plate | board thickness direction of the thick steel plate obtained by.
Claims (1)
し、0.05〜0.50m3/min・m2の水量密度で冷却を開始し、
その後0.30〜1.50m3/min・m2の水量密度になるまで徐々
に注水量を増加することを特徴とする板厚方向の材質差
の少ない厚鋼板の製造法。1. When accelerating cooling a thick steel plate after hot rolling, cooling is started at a water density of 0.05 to 0.50 m 3 / min · m 2 ,
After that, the method for producing a thick steel plate with a small material difference in the plate thickness direction is characterized in that the water injection amount is gradually increased until the water amount density becomes 0.30 to 1.50 m 3 / min · m 2 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61166456A JPH0747769B2 (en) | 1986-07-15 | 1986-07-15 | Manufacturing method of thick steel plate with little material difference in thickness direction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61166456A JPH0747769B2 (en) | 1986-07-15 | 1986-07-15 | Manufacturing method of thick steel plate with little material difference in thickness direction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6320410A JPS6320410A (en) | 1988-01-28 |
| JPH0747769B2 true JPH0747769B2 (en) | 1995-05-24 |
Family
ID=15831738
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61166456A Expired - Fee Related JPH0747769B2 (en) | 1986-07-15 | 1986-07-15 | Manufacturing method of thick steel plate with little material difference in thickness direction |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0747769B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04168216A (en) * | 1990-11-01 | 1992-06-16 | Kawasaki Steel Corp | Manufacture of thick steel plate small in difference of mechanical characteristics in the direction of plate thickness |
| CN100464886C (en) * | 2003-06-13 | 2009-03-04 | 杰富意钢铁株式会社 | Controlled cooling device and controlled cooling method for thick steel plate |
| JP2011144455A (en) * | 2004-03-25 | 2011-07-28 | Jfe Steel Corp | Method for producing large thickness low yield ratio high-tensile steel plate |
| JP5515483B2 (en) * | 2009-07-27 | 2014-06-11 | Ｊｆｅスチール株式会社 | Thick steel plate cooling equipment and cooling method |
| CN119566076A (en) * | 2024-11-19 | 2025-03-07 | 阳春新钢铁有限责任公司 | A process control method for reducing the performance difference between the head and tail of wire products |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58120725A (en) * | 1982-01-09 | 1983-07-18 | Nippon Steel Corp | Manufacture of nontemper 50kg steel having high toughness and high weldability |
-
1986
- 1986-07-15 JP JP61166456A patent/JPH0747769B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6320410A (en) | 1988-01-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |