Method for improving thermoplasticity of super austenitic stainless steel

Abstract

The invention belongs to the field of super austenitic stainless steel smelting and processing and provides a method for improving the thermoplasticity of super austenitic stainless steel. The method is suitable for smelting the super austenitic stainless steel with smaller than or equal to 0.02% of C, smaller than or equal to 0.5% of Si Mn, 2.0-4.0% of Mn, 24.0-25.0% of Cr, 21.0-23.0% of Ni, 7.0-8.0% of Mo, 0.3-0.6% of Cu, 0.45-0.55% of N, smaller than or equal to 0.005% of S, smaller than or equal to 0.03% of P and the balance Fe and other inevitable impurity elements, and 0.01-0.10% of rare earth and 0.001-0.008% of boron are added into the steel on the basis. The method is characterized by comprising the steps of preparing and placing materials; vacuumizing a furnace until the pressure is less than 5 Pa, and electrifying and heating the furnace; introducing nitrogen into the furnace after melting down until the pressure is 0.08-0.10 MPa, and sequentially adding chromium nitride, a deoxidizing agent and a desulfurizing agent; after deep deoxidation and desulfurization, sequentially adding the rare earth and the boron; and filling the furnace with the nitrogen again until the pressure is 0.10-0.12MPa, and carrying out casting. The method has the advantages that by adopting the mode of compound addition of the boron and the rare earth, the plasticity of the steel is remarkably improved, the hot working performance of the steel is improved, the technical bottleneck of hot rolling cracking is broken through, and a technical support is provided for obtaining a super austenite stainless steel product with high surface quality and excellent performance.

Description

technical field [0001] The invention belongs to the field of super austenitic stainless steel smelting and processing, and in particular relates to a method for compounding boron and rare earth to improve the thermoplasticity of super austenitic stainless steel. [0002] technical background [0003] Super austenitic stainless steel is an austenitic alloy whose alloy content (chromium, molybdenum, nickel, nitrogen, etc.) is significantly higher than that of ordinary austenitic stainless steel. Excellent pitting corrosion resistance, crevice corrosion resistance and stress corrosion resistance are widely used in seawater desalination treatment systems, pulp bleaching systems, hydrometallurgical equipment and other fields. However, the high alloy content significantly increases the high-temperature deformation resistance of this type of steel, and the thermoplasticity deteriorates sharply. It is very easy to crack during hot working, especially the edge crack is very serious. ...

AI Technical Summary

Problems solved by technology

However, when excessive rare earth is added, large rare earth inclusions will appear in the steel, which will deteriorate the performance of the steel

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