Method for improving pit defects on surface of 254SMo stainless steel

Abstract

The invention discloses a method for improving pit defects on the surface of 254SMo stainless steel, which is characterized by comprising the following steps of: performing cold rolling annealing at the temperature of between 1,150 and 1,170 DEG C for 3 to 5 minutes; carrying out electrolytic pickling, specifically, and using a Na2SO4 solution, wherein the specific gravity is 1.16-1.24, the current is 2000-3000 A, the temperature is 70-75 DEG C, and the electrolytic pickling time is 3.5-5.5 Min; carrying out brushing, specifically, and using bristles made of silicon carbide, wherein the rotating speed of the bristles is 950-1050 rpm, and the brushing current is 120-130 A; and carrying out mixed acid pickling, wherein a mixed solution of hydrofluoric acid and nitric acid is used, the concentration of the hydrofluoric acid is 35-40 g/l, the concentration of the nitric acid is 70-80 g/l, and the temperature of the mixed acid solution is 60-65 DEG C; the method has the advantages that theobtained 254SMo stainless steel is good in surface state, pit-related defects are avoided, oxide scales are completely removed, and the designed corrosion resistance is achieved.

Description

technical field [0001] The invention belongs to the technical field of cold annealing and pickling of stainless steel, and in particular relates to a method for improving pit defects on the surface of 254SMo stainless steel. Background technique [0002] 254SMo is a super austenitic stainless steel with C (carbon) content <0.03%. 254SMo stainless steel has good uniform corrosion resistance and is especially suitable for halide-containing environments such as seawater. Since 254SMo stainless steel is a high-alloy material, the manufacturing process is quite complicated, and generally it can only be manufactured by traditional processes. In the prior art, after the steel strip passes through the cold annealing and pickling process, the surface of the steel strip is severely damaged, and dense small pit defects are formed, which affects the surface appearance and corrosion resistance of the 254SMo steel. Contents of the invention [0003] In order to overcome the deficie...

AI Technical Summary

Problems solved by technology

Since 254SMo stainless steel is a high-alloy material, the manufacturing process is quite complicated, and generally it can only be manufactured by traditional processes.

In the prior art, the surface of the strip steel is severely damaged after the cold annealing and pickling process, forming dense small pit defects, which affects the surface appearance and corrosion resistance of 254SMo steel

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