Reversal austenite toughened martensitic stainless steel and manufacturing method thereof

Abstract

The invention discloses reversal austenite toughened martensitic stainless steel and a manufacturing method thereof. The stainless steel comprises, by mass percent, 0.001 to 0.40% of C, 11.0 to 22.0%of Cr, 1.0 to 12.0% of Ni, 0 to 3.0% of Mo, 0.07 to 1.50% of Ti, 0.05 to 1.50% of Al, 0.10 to 2.0% of Si and the balance Fe and inevitable impurities. The manufacturing method of the stainless steel comprises the steps that firstly, an electric furnace is used for smelting, and an AOD furnace is used for refining and casting to form a steel ingot; hot rolling or hot forging treatment is carried out; austenitizing is carried out, and air cooling quenching is carried out; deep cooling treatment is carried out; tempering is carried out. The thermodynamics condition formed by the reversal austenite and the martensite transformation principle serve as the reference, the fine dispersion nucleation position is created for the reversal austenite, the austenite heat stability is improved, a large amount of thin long strip reversal austenite is formed between martensite strips, and toughness plasticity of the martensite stainless steel can be obviously improved.

Description

technical field [0001] The invention belongs to the field of alloy steel, and relates to a martensitic stainless steel with reversed austenite toughening and a manufacturing method thereof, and is especially suitable for high strength, toughness and corrosion resistance in aerospace, thermal power nuclear power, household appliances, automobile industry, precision medical equipment, etc. steel. Background technique [0002] Martensitic stainless steel has high tensile strength, good ductility, good corrosion resistance and machinability, and low cost. At present, this type of steel is mainly used in seamless pipes and pipelines for offshore oil and gas development, wet natural gas processing facilities, hydropower, compressor impellers, nuclear power plant castings and pressure vessels. [0003] Its excellent performance comes from its special microstructure. After proper quenching and tempering heat treatment, its structure is a two-phase structure of tempered martensite ...

AI Technical Summary

Problems solved by technology

In order to make the reversed austenite finer, more interfaces are formed through repeated phase transformations to provide nucleation sites for the reversed austenite, but the growth behavior of the reversed austenite cannot be effectively controlled, so the size of the reversed austenite is generally smaller. Large, once transformed into martensite during deformation, it will become an important factor inducing cracks and endangering plasticity and toughness

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