Method for eliminating surface cracks of ultra-wide-amplitude saving type double-phase stainless steel medium-thick plate

Abstract

The invention discloses a method for eliminating surface cracks of an ultra-wide-amplitude saving type double-phase stainless steel medium-thick plate. A high-hardness ultrafine grain region with thethickness of 5-10 mm is formed on the upper surface and the lower surface of a continuous casting blank and the medium axis crystal proportion of the continuous casting blank is not lower than 75%, and the surface layer superfine crystal region is free of brittle phase separation; the casting blank is subjected to a preheating section, a heating section and a soaking section, and the casting blankis in the furnace 3.5-4.5 hours; the rolling temperature in the first stage is larger than or equal to 1150 DEG C; and the rolling temperature in the second stage is larger than or equal to 1100 DEGC, the final rolling temperature is larger than or equal to 980 DEG C, the solution temperature is 1020-1080 DEG C, and the furnace time is 2-5 min / mm. The product has the width of 2800-4000 mm and the thickness of 15-60 mm. The yield strength of the steel plate is larger than or equal to 450 MPa, the tensile strength is more than or equal to 650 MPa, the elongation percentage is larger than or equal to 30%, and the impact power is larger than or equal to 27J at at 40 DEG C below zero. The rejection rate of the surface cracks is reduced to be 1% or below from 10% or above. The product is applied to the fields of nuclear power, oil gas, shipbuilding, sea water desalination and the like.

Description

technical field [0001] The invention relates to the technical field of duplex stainless steel plate rolling, in particular to a method for eliminating surface cracks of an ultra-wide economical duplex stainless steel plate. Background technique [0002] With the rapid development of domestic shipbuilding, chemical industry, nuclear power, shipbuilding industry and other industries in recent years, the demand for low-cost duplex stainless steel plates with high strength and excellent corrosion resistance is increasing day by day. , Higher toughness, no room temperature brittleness, good intergranular corrosion resistance and welding performance, so it is widely used in the fields of petroleum, chemical industry and nuclear power. Due to the poor thermoplasticity of economical duplex stainless steel, hot forming is restricting its ability A key factor for successful production. At present, there is an increasing demand for wide and large-size economical stainless steel hot-ro...

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Problems solved by technology

However, this method does not consider optimizing the steelmaking, continuous casting process and continuous casting slab surface strengthening quenching process to improve the quality and structure of 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 , and did not consider the influence factor of the width ratio (the width of the steel plate after rolling was not clarified)

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