Ni-saving austenitic stainless steel cold-rolled sheet with excellent processability and manufacturing method thereof

Abstract

The invention relates to an Ni-saving austenitic stainless steel with excellent processability. The austenitic stainless steel comprises one or two of the following chemical components in percentage by weight: 0.06-0.12 of C, 0.2-1.0 of Si, 7.0-9.0 of Mn, 17.0-18.5 of Cr, 3.01-3.45 of Ni, 0.15-0.22 of N, 0.01-0.2 of Mo, 1.2-1.9 of Cu, B larger than or equal to 0.001% and smaller than or equal to 0.004%, Ca larger than or equal to 0.001% and smaller than or equal to 0.005%, V smaller than or equal to 0.1%, Nb smaller than or equal to 0.1%, and the balance of Fe and unavoidable impurities, wherein the sum of the percentage of C and the percentage of N is larger than or equal to 0.25%. The manufacturing method of the austenitic stainless steel comprises the following steps: heating a smelted and poured casting blank to 1100-1250 DEG C and preserving heat, performing hot working on the casting blank until a needed thickness is obtained, wherein the heat preserving time is more than 30min; after hot working, annealing at a controlled temperature of 980-1100 DEG C and washing the blank with any acid, and performing cold rolling, wherein when Md30 / 50 is larger than or equal to -30 DEG C and smaller than or equal to 0 DEG C, the maximum cold rolling deformation is 75-80%; or when Md30 / 50 is smaller than or equal to -30 DEG C, the maximum cold rolling deformation is 80-85%. According to the invention, the cold working performance of the Ni-saving austenitic stainless steel is improved; the corrosion resistance is close to that of type 304, and meanwhile the cost is lower than that of the type 304.

Description

technical field [0001] The invention relates to a nickel-saving austenitic stainless steel and a manufacturing method thereof, in particular to a nickel-saving austenitic stainless steel cold-rolled plate with excellent processing performance and a manufacturing method thereof. Background technique [0002] The most widely used 300-series austenitic stainless steel usually contains 8% to 12% nickel, and the cost of nickel element accounts for about 80% of the cost of raw materials. Since 2005, the price of nickel, an important alloying element in stainless steel, has continued to rise, leading to an increase in the cost of raw materials for stainless steel production. At the same time, it is predicted that the shortage of rare and precious metal nickel has a certain long-term nature. This makes reducing the cost of stainless steel production a key issue for the development of iron and steel enterprises. Every 1% reduction in nickel in stainless steel means a 10-15% reductio...

AI Technical Summary

Problems solved by technology

However, after the expensive element Ni is replaced by N, the higher N content leads to increased lattice distortion and increased difficulty in plastic deformation of the metal. Therefore, the deformation resistance during thermal processing is large, and defects such as edge cracks are prone to occur, resulting in scrapped materials. Or the yield rate is reduced, especially when the nitrogen content is greater than 0.15%, hot working is more difficult; (2) cold working is difficult, and the alloy content in 200 series stainless steel is low, especially the austenite forming and stabilizing element Ni content is low , causing its austenite phase to be metastable. During cold working, the metastable austenite phase will transform into a brittle martensite phase. The generation of martensite phase will lead to a rapid increase in the degree of work hardening, and the hardness and strength of the material Rapidly rising, the deformation difficulty of continuing cold working increases, and at the same time, because the martensitic phase is brittle, the steel strip is prone to brittle fracture during processing, resulting in product scrap

[0012] On the other hand, the Cr content in some patented composition systems is much lower than 18% in 304 austenitic stainless steel, which reduces the corrosion resistance and increases the risk of corrosion

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