Low-cost high-strength low nickel austenitic stainless steel and manufacturing method thereof

Abstract

The invention relates to a low-cost high-strength stainless steel and a manufacturing method thereof. The stainless steel comprises the following the chemical components by weight percentage: 0.05-0.15% of C, 0.2-1.0% of Si, 7-12% of Mn, 14-16% of Cr, 1. 0 to 2.0% of Ni, less than or equal to 0.045% of P, less than or equal to 0.02% of S, 0.1-0.2% of N, 1.0-2.0% of Cu, and 0.05-0.2% of Al, and thebalance of Fe and inevitable impurities. By adding an Al element and controlling the content of Al in the steel, and under small deformation variable, only a small amount of martensite is induced when the steel is subjected to deformation (the formation of a large amount of martensite increases the delayed cracking sensitivity of the steel), high plasticity and elongation percentage can achieve more than 30%, and due to three effects of the precipitation strengthening of AlN and the deformation strengthening and phase-transformation strengthening of steel, the yield strength of steel is morethan 800 MPa, and the tensile strength is above 1000 MPa, the stainless steel meets the requirements of high strength and high plasticity of an automobile frame and an automobile beam steel and structural parts, and achieves the objects of lightweight, high safety performance and high corrosion resistance of automobiles.

Description

technical field [0001] The present invention relates to austenitic stainless steel and a manufacturing method, in particular to a low-cost high-strength nickel-saving austenitic stainless steel and a manufacturing method. The austenitic stainless steel has a yield strength of more than 800 MPa, a tensile strength of more than 1000 MPa, and high plasticity. The elongation rate reaches more than 30%, and it can be used in auto parts, especially suitable for bus frame, auto girder and other structural parts. Background technique [0002] Environmental pollution affects health, and automobile emissions have become one of the main sources of air pollution. Therefore, countries around the world have introduced stricter vehicle emission standards. Automobile lightweight can improve vehicle power, reduce fuel consumption, and reduce emissions. Therefore, automobile lightweight has become the world's automotive technology. One of the important directions of development. Lightweight ...

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Problems solved by technology

[0012] In summary, all of the above patents are nickel-saving austenitic stainless steels. Except for the high-manganese steel disclosed in 201580016940.2, which induces plasticity through deformation twins, the nickel-saving austenitic stainless steels in other patents are all metastable. After deformation, martensite will be produced, and the generation of certain martensite can induce plasticity while producing high strength, but excessive martensite content in steel and excessive stress state in steel will cause delayed cracking of the material,

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