Method for eliminating surface cracks of ultra-wide ferrite stainless steel middle-thick plate

Abstract

The invention discloses a method for eliminating surface cracks of an ultra-wide ferrite stainless steel middle-thick plate. The proportion of the medium axis crystal of a continuous cast blank is notlower than 75%; the homogenization temperature of the cast blank is 750-850 DEG C, the duration in the furnace is 1-2 hours, and water cooling is carried out to the room temperature; the surface roughness Ra of the cast blank after grinding is less than or equal to 70 microns, and high-temperature antioxidant coating is sprayed; the cast blank is processed by a preheating section, a heating section and a soaking section in sequence, and then is discharged from the furnace; the temperature of the preheating section is 950-1180 DEG C, the temperature of the heating section is 1180-1260 DEG C, the temperature of the soaking section is 1220-1250 DEG C, and the furnace time is 4-5.5 hours; the rough rolling temperature is larger than or equal to 1150 DEG C; the finish rolling temperature is larger than or equal to 1150 DEG C, the final rolling temperature is larger than or equal to 950 DEG C, the rolling single-pass pressing rate is less than or equal to 20%, the annealing temperature is 750-880 DEG C, the furnace time is 2-5 min / mm, and air cooling is carried out. The product width is 2500-4000 mm and the thickness is 8-30 mm. The rejection rate of the surface cracks is reduced from 6% or above to 0.5% or below.

Description

technical field [0001] The invention relates to the technical field of rolling ferritic stainless steel plates, in particular to a method for eliminating surface cracks in ultra-wide ferritic stainless steel plates. The ferritic stainless steel plates are mainly suitable for high toughness and impact Loaded structural members. Background technique [0002] With the rapid development of high-rise domestic building structures, nuclear power safety equipment, water vapor pressure vessels, and shipbuilding industries in recent years, the demand for ultra-wide ferritic stainless steel plates is increasing day by day. The characteristics of large coefficient, small expansion coefficient, good oxidation resistance and excellent stress corrosion resistance have attracted more and more attention in the industrial field, especially the medium chromium ferritic stainless steel occupies a very important position in the application field of ferritic stainless steel . Compared with low-...

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Problems solved by technology

However, this method does not consider optimizing the steelmaking and continuous casting process to improve the proportion of equiaxed grains in the continuous casting slab, and does not consider the impact of grinding and spraying on the surface of the stainless steel on the surface quality of the plate

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