Control method of softness of oxide scales on surface of hot-rolling strip steel

A technology of surface oxidation and hot-rolled strip, applied in metal rolling, metal rolling, temperature control and other directions, can solve the problems of increasing equipment investment, natural cooling can not meet the requirements, etc., to reduce FeO broken, reduce thickness, improve The effect of adhesion

Active Publication Date: 2010-10-13
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The technology disclosed in the Japanese patent (Patent No. 06-033449) requires the cooling speed of the hot-rolled coil to be above 1°C / s in order to obtain dense iron oxide scale. Natural cooling cannot meet the requirements, which requires industrial fans and water-cooled spray shower cooling, increased equipment investment
In addition, the structure of iron oxide scale in this technology is Fe 3 o 4 -FeO-Fe 3 o 4 Three-layer structure, the steel plate obtained in this way is in the occasion of deep processing, and the adhesion of the oxide scale has yet to be verified.

Method used

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  • Control method of softness of oxide scales on surface of hot-rolling strip steel
  • Control method of softness of oxide scales on surface of hot-rolling strip steel
  • Control method of softness of oxide scales on surface of hot-rolling strip steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Smelting molten steel and continuous casting into slabs, its composition by weight percentage is C 0.098%, Si 0.23%, Mn 1.26%, P0.016%, S0.002%, Al 0.032%, Nb 0.020%, V0.001%, Ti0.003%, balance is iron.

[0045] Heat the slab to 1220°C and keep it warm for 40 minutes. Then use high-pressure water to descale, the temperature of descaling is 1200℃, and the water pressure is required to be 20MPa when descaling.

[0046] The descaled slab is subjected to rough rolling, the starting rolling temperature is 1150° C., the finishing rolling temperature is 1030° C., and the accumulated rolling reduction is 78%.

[0047] The slab after rough rolling is descaled before finishing rolling, the descaling temperature is 1050°C, and the water pressure is at least 18MPa during the second descaling; then finish rolling, the finish rolling start temperature is 1020°C, and the final rolling temperature is 870 ℃, the cumulative reduction in finish rolling is 75%, and the rolling speed duri...

Embodiment 2

[0049] Smelting molten steel and continuously casting it into slabs, its composition by weight percentage is C 0.071%, Si 0.131%, Mn 1.485%, P0.006%, S0.003%, Al 0.044%, Nb 0.062%, V0.016%, Ti0.002%, balance is iron.

[0050] Heat the slab to 1250°C and keep it warm for 40 minutes. , and then use high-pressure water to descale, the temperature of descaling is 1220℃, and the water pressure is required to be 20MPa when descaling.

[0051] The descaled slab is subjected to rough rolling, the rolling start temperature is 1180° C., the final rolling temperature is 1060° C., and the cumulative reduction is 85%.

[0052] The slab after rough rolling is descaled after finishing rolling, the descaling temperature is 1080°C, and the water pressure is at least 18MPa during descaling; then finish rolling, the finish rolling start temperature is 1040°C, and the final rolling temperature is 880°C, The cumulative reduction in finish rolling is 75%, and the rolling speed during finish rolli...

Embodiment 3

[0054] Smelting molten steel and continuously casting it into slabs, its composition by weight percentage is C 0.089%, Si 0.074%, Mn 1.282%, P0.007%, S0.002%, Al 0.041%, Nb 0.020%, Ti0.001%, The balance is iron.

[0055] Heat the slab to 1230°C, keep it warm for 30 minutes, and then use high-pressure water to descale. The descaling temperature is 1200°C, and the water pressure is required to be 20-25MPa during descaling.

[0056] The descaled slab is subjected to rough rolling, the starting rolling temperature is 1170°C, the finishing rolling temperature is 1080°C, and the accumulated rolling reduction is 83%.

[0057] The slab after rough rolling is descaled before finish rolling, the descaling temperature is 1100°C, and the water pressure is at least 18MPa during descaling; then finish rolling, the finish rolling start temperature is 1070°C, and the final rolling temperature is 920°C, The cumulative reduction of finish rolling is 95%, and the rolling speed during finish rol...

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Abstract

The invention provides a control method of softness of oxide scales on the surface of hot-rolling strip steel, belonging to the technical field of metallurgy. The method comprises the following steps: smelting liquid steel and continuously casting into plate blanks, heating and conducting thermal insulation on the plate blanks, then descaling, and rough rolling; and descaling again, and then finish rolling, wherein the initial rolling temperature is 1020-1070 DEG C, the finish rolling temperature is 870-920 DEG C, the rolling reduction is 75-95%, and the rolling speed is 3.5-12 m / s; cooling to 500-650 DEG C at the speed of 8-25 DEG C / s; and coiling. Aiming to different oxide scales structures, a hot-rolling process regulation scheme is provided in the method. In the hot-rolling process regulation scheme, by controlling the cooling speed and coiling temperature and the degree of a eutectoid reaction of FeO, reasonable control of the structure of the oxide scales is achieved, and loss of mechanical properties of products, which is caused by high temperature rolling, is compensated. The production efficiency is improved by using the existing devices and process conditions in a steel plant, surface quality is improved on the premise of ensuring mechanical properties of the steel plate and flexible production of oxide scale control.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, in particular to a method for controlling the flexibility of oxide scales on the surface of hot-rolled steel strips. Background technique [0002] Due to the long-term lack of attention to the surface quality of ordinary carbon steel hot-rolled steel products in my country's metallurgical industry, these products often have problems such as red rust and iron sheet pressing due to improper control of the surface iron sheet, causing many quality objections or even returns, which seriously hinders the improvement of product grades . Therefore, in order to occupy a place in the highly competitive international market, it is necessary to develop a proprietary technology to solve the surface quality problems of our country's hot-rolled steel products. At the same time, in order to adapt to the basic policy of energy saving and emission reduction, the state is increasing the punishment of waste acid ...

Claims

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Application Information

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IPC IPC(8): B21B1/46B21B37/74B21B45/04C22C38/14
Inventor 刘振宇曹光明孙彬石发才崔天燮王立新李成刚贾涛王国栋
Owner NORTHEASTERN UNIV
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