Production method for duplex stainless steel hot-rolled coils

A technology of duplex stainless steel and production method, applied in the field of stainless steel smelting, can solve the problems of unreasonable control of duplex stainless steel, edge crack defects of duplex stainless steel, edge crack defects of hot-rolled sheets, etc. The effect of reducing the columnar crystal region

Active Publication Date: 2014-09-10
GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In the hot rolling production process, duplex stainless steel is prone to edge crack defects, which seriously restricts the production of this stainless steel
Many scientific researchers have studied the formation mechanism of edge crack defects in duplex stainless steel, and believe that the grain boundary of austenite and ferrite in duplex stainless steel is a relatively weak part of the bonding force, which is easy to form a crack source, and the crack source expands to form Edge crack defects; in the prior art, for the edge crack problem of duplex stainless steel hot-rolled plates produced by hot continuous rolling mills, measures are taken to control the heating temperature and edge heating to reduce the temperature drop of the strip during rolling and conveying to avoid edge cracking. However, this method still has problems such as duplex stainless steel Creq / Nieq ratio and unreasonable control of harmful elements, poor thermoplasticity of slab, improper heating control, etc., resulting in edge cracking defects of hot-rolled slabs

Method used

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  • Production method for duplex stainless steel hot-rolled coils
  • Production method for duplex stainless steel hot-rolled coils

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. Smelting

[0031] Duplex stainless steel desulfurization includes desulfurization in the reduction period in AOD furnace and deep desulfurization in LF furnace by slagging. The operation method of slagging desulfurization in LF furnace is to remove the slag after AOD is tapped, and add aluminum shot, lime and fluorite after LF enters the station. , stirring for 10 minutes using strong bottom blowing. Add 10kg / t steel lime and 3kg / t steel fluorite to the desulfurization stage in the AOD furnace, add 0.3Kg / t molten steel aluminum shot, 7.0Kg / t molten steel lime, and 4.0Kg / t molten steel fluorite to deep desulfurization in the LF furnace, The S content in the steel is controlled to be 0.0003%; the LF furnace is blown with argon throughout the process, and the treatment time is longer than 15 minutes, and the final fine-tuning of the composition is carried out to control the Creq / Nieq at 1.94 in order to uniform the composition and temperature; the amount of molten steel...

Embodiment 2

[0050] 1. Smelting

[0051] Duplex stainless steel desulfurization includes desulfurization in the reduction period in AOD furnace and deep desulfurization in LF furnace by slagging. The operation method of slagging desulfurization in LF furnace is to remove the slag after AOD is tapped, and add aluminum shot, lime and fluorite after LF enters the station. , stirring for 15 minutes using strong bottom blowing. Add 12kg / t steel lime and 5kg / t steel fluorite in the desulfurization stage of AOD furnace, add 0.2Kg / t molten steel aluminum shot, 5.0Kg / t molten steel lime, 5.0Kg / t molten steel fluorite for deep desulfurization in LF furnace, The S content in the steel is controlled to 0.0005%; the LF furnace is blown with argon throughout the process, and the treatment time is more than 15 minutes to uniform the composition and temperature, and the final fine-tuning of the composition is carried out so that the Creq / Nieq is controlled at 1.92; the amount of molten steel is 108.0 tons...

Embodiment 3

[0070] 1. Smelting

[0071] Duplex stainless steel desulfurization includes desulfurization in the reduction period in AOD furnace and deep desulfurization in LF furnace by slagging. The operation method of slagging desulfurization in LF furnace is to remove the slag after AOD is tapped, and add aluminum shot, lime and fluorite after LF enters the station. , stirring for 12 minutes using strong bottom blowing. Add 11kg / t steel lime and 4kg / t steel fluorite to the desulfurization stage in AOD furnace, add 0.25Kg / t molten steel aluminum shot, 6.0Kg / t molten steel lime, 3.0Kg / t molten steel fluorite to deep desulfurization in LF furnace, The S content in the steel is controlled to be 0.0007%; the LF furnace is blown with argon throughout the process, and the treatment time is more than 15 minutes to uniform the composition and temperature, and the final fine-tuning of the composition is carried out so that the Creq / Nieq is controlled at 1.97; the amount of molten steel is 105.8 t...

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Abstract

The invention relates to a production method for duplex stainless steel hot-rolled coils. The production method comprises such steps as smelting, continuous casting, slab polishing, tandem type slab heating, high-pressure water scale removal, rough rolling, rolling by a steekle mill and coiling; the content of S in steel is controlled below 0.0007%; Creq / Nieq is controlled within 1.92-1.97; the slab isometric crystal rate is controlled above 80%; the reasonable slab length and slab heating temperature are actually determined by combining with the scene; the process of slab high-pressure water scale removal one-gate and rough rolling frame non-scale removal is adopted; in particular, the rolling temperature of the hot rolling steekle mill is controlled; the produced stainless steel hot-rolled coils have no edge cracks, so that the yield is prominently improved; the problem of the edge crack defect generated by rolling the steel coils through the steekle mill in the rolling process is solved; and the edge quality of the hot-rolled steel coils is guaranteed.

Description

technical field [0001] The invention relates to the technical field of stainless steel smelting, in particular to a production method of duplex stainless steel hot-rolled coils. Background technique [0002] Duplex stainless steel is a typical N, Mo, ultra-low carbon, ferritic + austenitic duplex stainless steel. Due to the combination of the advantages of ferritic stainless steel and austenitic stainless steel, it has good mechanical properties and Anti-corrosion performance, widely used in shipbuilding, petroleum, chemical industry, papermaking and other fields. [0003] In the hot rolling production process, duplex stainless steel is prone to edge crack defects, which seriously restricts the production of this stainless steel. Many scientific researchers have studied the formation mechanism of edge crack defects in duplex stainless steel, and believe that the grain boundary of austenite and ferrite in duplex stainless steel is a relatively weak part of the bonding force,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/00C22C38/54
Inventor 陈兴润潘吉祥王建新白小军叶红刚魏海霞田矫健杨兆
Owner GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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