Production method of hot rolled steel coil for shipbuilding

A technology for a hot-rolled steel coil and a production method, which is applied to the improvement of process efficiency and other directions, can solve the problems of poor comprehensive performance of materials, large strength allowance, low elongation, etc., and achieves improved elongation, good surface quality, and simple method. Effect

Inactive Publication Date: 2013-01-09
NINGBO IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0025] It can be seen from Table 5 that the hot-rolled steel coil Q345 has a large strength margin, low elongation, poor overall material properties, and high Mn in the composition

Method used

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  • Production method of hot rolled steel coil for shipbuilding
  • Production method of hot rolled steel coil for shipbuilding
  • Production method of hot rolled steel coil for shipbuilding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] 1) After the composition is designed, the molten iron is pretreated, then smelted in a converter, nitrogen and argon are switched, and the molten steel is obtained after tapping; the supplementary blowing is performed once before tapping, and the tapping time is 4.5 minutes; the alloy is added before tapping 4 / 5; Tapping double slag blocking, the slag thickness at the arrival station is 80mm; the whole process of argon blowing at the argon station takes 17 minutes;

[0049] 2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.06%, Si 0.20%, Mn 0.90%, P0.010%, S 0.005%, Nb+Ti+V 0.040%, Als 0.020%, the rest It is iron and unavoidable impurities; the molten steel is continuously cast to obtain a slab, wherein the molten steel in the tundish is 25t and the liquid level is 550mm when the tundish is opened in the first continuous casting furnace; the molten steel in the tundish is 15t when the tundish is quickly chan...

Embodiment 2

[0053] 1) After the composition is designed, the molten iron is pretreated, then smelted in a converter, nitrogen and argon are switched, and the molten steel is obtained after tapping; 0 times of supplementary blowing before tapping, and the tapping time is 6.0min; the alloy is added before tapping 4 / 5; Tapping double slag blocking, the slag thickness at the arrival station is 60mm; the argon station handles the whole process of blowing argon for 25 minutes;

[0054]2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.07%, Si 0.25%, Mn 1.0%, P 0.015%, S 0.010%, Nb+Ti+V 0.050%, Als 0.025%, the rest It is iron and unavoidable impurities; the molten steel is continuously cast to obtain a slab, wherein the amount of molten steel in the tundish is 30t and the liquid level is 560mm when the tundish is opened in the first furnace of continuous casting; the amount of molten steel in the tundish is 18t when the tundish is qui...

Embodiment 3

[0058] 1) After the composition is designed, the molten iron is pretreated, then smelted in the converter, nitrogen and argon are switched, and the molten steel is obtained after tapping; the supplementary blowing is performed once before tapping, and the tapping time is 8.0min; the alloy is added before tapping 4 / 5; Tapping double slag blocking, the slag thickness at the arrival station is 30mm; the whole process of argon blowing at the argon station is 30min;

[0059] 2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.08%, Si 0.30%, Mn 1.10%, P0.020%, S 0.015%, Nb+Ti+V 0.062%, Als 0.030%, the rest Iron and unavoidable impurities; the molten steel is continuously cast to obtain a slab, wherein the molten steel in the tundish is 28t and the liquid level is 580mm when the tundish is opened in the first continuous casting furnace; the molten steel in the tundish is 20t when the tundish is quickly changed , the liquid...

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Abstract

The invention relates to a production method of hot rolled steel coil for shipbuilding. The method comprises the following steps of: (1) designing contents, preprocessing molten iron, then, smelting in a converter, switching nitrogen and argon and tapping to obtain molten iron; (2) continuously casting the molten iron to obtain a plate blank, controlling the molten iron amount to be 8-15t and theliquid level to be 200-350 mm when stopping casting a continuous casting tundish and wholly protecting and casting while the insertion depth of a long water opening is 300-400 mm; (3) heating the plate blank; and (4) finally, rolling and coiling the heated plate blank. The invention adopts a RPC (Relaxation-Precipitation-phase Control) and TMCP (Thermomechnical Control Process) rolling process, decreases the C and Mn contents by utilizing niobium microalloying treatment and decreases production cost. The D32-level hot rolled steel coil for shipbuilding has excellent plasticity and toughness, the extensibility is improved by over 8 percent, the welding performance of the material is improved and the favorable surface quality of a continuous casting blank is ensured.

Description

technical field [0001] The invention belongs to the field of preparation of hot-rolled steel coils, in particular to a production method of hot-rolled steel coils for shipbuilding. Background technique [0002] The current production of steel coils with a yield strength of 345MPa is high in the composition of each steel plant, with many cracks on the surface of the billet, a large margin of strength, and low plasticity and toughness. Large strength margin affects cold working performance; there is a high probability of cracks on the surface of the billet and cannot be directly installed, which is not conducive to energy saving and emission reduction; high C content, poor welding performance; high Mn content in steel, high production costs, and product market competition The ability is poor; the steel rolling adopts any rolling process, and the performance of the product fluctuates in a large range, which is not conducive to the use of users. [0003] Investigation on produc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/04C22C33/04C21D8/02
CPCY02P10/20
Inventor 杨云清曹太平丘祥光于长春柳晨岚蒋鲜林周德峰张建方
Owner NINGBO IRON & STEEL
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