Two-phase stainless steel alloy and preparation method thereof

Abstract

The invention discloses a two-phase stainless steel alloy and a preparation method thereof. The two-phase stainless steel alloy is composed of the following chemical components in percentage by mass: 0.01-0.03 percent of C, 0.1-2.0 percent of Si, 1.0-3.0 percent of Mn, 20-22 percent of Cr, 1.7-2.5 percent of Ni, 0.7-1.0 percent of Cu, 0.1-0.2 percent of N, 0.2-1.0 percent of W, as well as Fe and unavoidable impurity elements in balancing amount. According to the invention, the two-phase stainless steel has good performance of mechanics, hot working performance and high corrosion resistance, and can be manufactured by the prior art. The adopted low-cost N and Mn substitute Ni to stabilize the Austenite phase of the two-phase stainless steel, and the low-cost W substitutes Mo, so that the cost is lowered; and meanwhile, the lower content of the element M is controlled via reasonably regulating the mixture ratio of the elements Ni, N and Mn, a situation that low-melting-point sulphides exist at a phase boundary is avoided, and the hot working performance of the two-phase stainless steel is effectively ameliorated.

Description

Technical field [0001] The invention relates to a duplex stainless steel alloy and a preparation method thereof, and belongs to the field of stainless steel metallurgy. Background technique [0002] Duplex stainless steel refers to a stainless steel whose solid solution structure is composed of two phases of ferrite and austenite, and one of the phase ratios is about 45%-55% (the less phase accounts for at least 30%). Due to the characteristics of the two-phase structure, the duplex stainless steel has the advantages of both ferritic stainless steel and austenitic stainless steel. Compared with ferritic stainless steel, it has high toughness, low brittle transition temperature, resistance to intergranular corrosion and good welding performance. It retains the advantages of high thermal conductivity and small expansion coefficient of ferritic steel. Compared with austenitic stainless steel, its yield strength is about twice that of austenitic stainless steel, and its resistance t...

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Problems solved by technology

[0009] The patent application number is 200810032407.7: Compared with the patent 201110186769.3, this patent reduces the content of nickel, but the content of manganese does not increase accordingly, which makes it difficult to ensure the stability of the two-phase structure and increases the difficulty of thermal processing

[0010] The patent application number is 200810079771.9: this patent is the same as the patent 201110186769.3, which has the problems of poor stability of the two-phase structure and poor thermal processing performance

[0011] According to the above analysis, although there are many low-nickel duplex stainless steels, their cost has been greatly reduced compared with 304 and 316L stainless steel, but there are still problems: the cost control and thermal processing of these invention patent alloys The performance matching has not been optimized, that is, some patents use too little nickel content, resulting in an increase in the content of manganese and nitrogen, poor thermal processing performance, reduced material yield, and the overall cost of the final material has not been reduced; some patents The content of manganese and nitrogen is too low. In order to ensure the stability of the two phases, the content of nickel is relatively high. Although the thermal processing performance is better, the cost of the material becomes higher due to the increase of nickel.

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