Method for producing hot-rolled steel coil

A technology of hot-rolled steel coils and production methods, applied in the direction of improving process efficiency, etc., can solve the problems of low plasticity and large strength margin of hot-rolled steel coils, reduce production costs, avoid bending cracking problems, reduce alloy The effect of dosage

Inactive Publication Date: 2011-07-20
NINGBO IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0026] It can be seen from Table 6 that the series of hot-rolled steel coils with a yield strength of 235MPa has a large margin of strength and low plasticity

Method used

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  • Method for producing hot-rolled steel coil
  • Method for producing hot-rolled steel coil
  • Method for producing hot-rolled steel coil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] 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;

[0050] 2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.05%, Si 0.12%, Mn 0.40%, P 0.015%, S 0.010%, Als 0.020%, and the rest are iron and unavoidable impurities; The molten steel is continuously cast to obtain a slab, wherein the molten steel volume of the tundish is 25t and the liquid level is 550mm when the tundish is poured in the first continuous casting furnace; the molten steel volume is 15t and the liquid level is 350mm when the tundish...

Embodiment 2

[0054] 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 from 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;

[0055] 2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.07%, Si 0.17%, Mn 0.51%, P 0.020%, S 0.015%, Als 0.025%, and the rest are iron and unavoidable impurities; The molten steel is continuously cast to obtain a slab, wherein the tundish molten steel volume is 30t and the liquid level is 560mm when the tundish is poured in the first continuous casting furnace; the tundish molten steel volume is 18t and the liquid level is 380mm when the tundish is quickly...

Embodiment 3

[0059] 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;

[0060] 2) The weight percentages of the components of the above-mentioned molten steel after tapping are as follows: C 0.09%, Si 0.24%, Mn 0.62%, P 0.025%, S 0.020%, Als 0.040%, and the rest are iron and unavoidable impurities; The molten steel is continuously cast to obtain a slab, wherein the amount of molten steel in the tundish is 28t and the liquid level is 580mm when the tundish is poured in the first furnace of continuous casting; The amount of molten steel in the tundish is kept at 50t, and the liquid level is...

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Abstract

The invention relates to a method for producing a hot-rolled steel coil, which comprises the following steps of: 1) designing components, pretreating molten iron, smelting in a converter, switching nitrogen and argon, and tapping to obtain molten steel; 2) performing continuous casting on the molten steel to obtain a plate blank, wherein the content of the molten steel in a continuously cast intermediate ladle is controlled to be between 8 and 15t and the liquid level is controlled to be between 200 and 350mm when the intermediate ladle is not poured; and pouring is protected in the whole process, and the insertion depth of a long nozzle is between 300 and 400mm; 3) heating the plate blank; and 4) rolling and curling the heated plate blank. By the method, the content of C and Mn in the components of Q235q-D steel is reduced, the comprehensive performance of the Q235q-D steel is improved by appropriate rolling process and controlled cooling process, and a low-cost and high-performance Q235q-D hot-rolled steel coil is produced.

Description

technical field [0001] The invention belongs to the field of steel coil preparation, in particular to a production method of hot-rolled steel coils. Background technique [0002] The currently produced series steel coils with a yield strength of 235MPa have high C in composition, many cracks on the surface of the slab, large strength margin, and low plasticity and toughness. When the lower limit of Mn is required in special steel, its strength margin will be greater, which will affect the cold working performance; the surface of the slab has a high probability of cracks and cannot be directly installed, which is not conducive to energy saving and emission reduction; high C content, poor welding performance. [0003] Investigation on Production Performance of Series Steel Coils with Yield Strength 235MPa [0004] Table 1 Statistical Table of Thickness and Performance Range of Steel Coils with Yield Strength 235MPa [0005] [0006] It can be seen from Table 1 that: [0...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C33/04C21D8/02
CPCY02P10/20
Inventor 杨云清孔祥胜丘祥光刘万善刘玲月肖建奇刘义
Owner NINGBO IRON & STEEL
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