Method for eliminating surface cracks of ultra-wide high-nitrogen austenitic stainless steel medium thick plate

Abstract

The invention discloses a method for eliminating surface cracks of an ultra-wide high-nitrogen austenitic stainless steel medium thick plate. The isometric crystal proportion in a continuous casting blank is not lower than 85%; the surface roughness degree Ra of the casting blank after being subjected to repairing grinding is smaller than or equal to 100 microns, and high-temperature anti-oxidizing coating is sprayed; after being treated through a pre-heating segment at a temperature of 980-1100 DEG C, a heating segment at a temperature of 1100-1230 DEG C, and a soaking zone at a temperature of 1200-1230 DEG C in sequence, the casting blank is discharged out of a furnace, and the in-furnace time is 3-4 h; the initial rolling temperature in the first stage is larger than or equal to 1150 DEG C, and the final rolling temperature is larger than or equal to 950 DEG C; and the initial rolling temperature in the second stage is larger than or equal to 1120 DEG C, the final rolling temperature is larger than or equal to 950 DEG C, a high-temperature solid solution temperature is 980-1050 DEG C, the in-furnace time is 2-5 min / mm, and water cooling is performed till a room temperature is achieved. A product width is 2200-4000 mm, and the thickness is 20-60 mm. A surface crack rejection ratio is lowered to be 2% or below from 10% or above. A product is suitable for a structural part highin toughness and high in strength and bearing an impacting load.

Description

technical field [0001] The invention relates to the technical field of austenitic stainless steel plate rolling, in particular to a method for eliminating surface cracks of an ultra-wide high-nitrogen austenitic stainless steel plate. Background technique [0002] With the rapid development of domestic wind tunnel laboratory construction for large aircraft experiments, water vapor pressure vessels, nuclear power safety equipment, shipbuilding industry and other industries in recent years, the medium thickness of austenitic stainless steel with high low temperature tensile strength and high toughness The demand for plates is increasing day by day. Nitrogen-containing austenitic stainless steel is widely used in the fields of petroleum, chemical industry, aerospace and energy due to its good ductility, cold and hot processing performance and local corrosion resistance at high and extremely low temperatures. , These fields require materials to be used at a temperature as low as...

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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 stainless steel on the surface quality of the plate, nor does it consider the widening ratio. Influencing factors (the width of the steel plate after rolling is not specified)

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