CN-116511531-B - Preparation method of high-nitrogen nickel-free austenitic stainless steel member

Abstract

The invention provides a preparation method of a high-nitrogen nickel-free austenitic stainless steel component, which is based on the existing national standard ferrite stainless steel and heat-resistant steel S12791 and S13091 powder, and prepares the high-nitrogen nickel-free austenitic stainless steel component by in-situ addition of MnN laser additive manufacturing, so as to solve the problems of complex traditional preparation process, high cost, long period and the like of the existing high-nitrogen nickel-free austenitic stainless steel component, and the problems of difficult acquisition of laser additive manufacturing powder raw materials and the like, and the problems of immature development of special high-nitrogen nickel-free austenitic stainless steel components and the like, belonging to the additive manufacturing field.

Inventors

• YU CHAOJING
• ZHANG DABIN
• HU RUIFENG
• Zhong Yinliang

Assignees

• 茅台学院
• 贵州大学

Dates

Publication Date

20260508

Application Date

20230429

Claims (1)

1. 1. The preparation method of the high-nitrogen nickel-free austenitic stainless steel member is characterized in that the method is based on the existing national standard ferrite stainless steel and heat-resistant steel S12791 and S13091 powder, and the high-nitrogen nickel-free austenitic stainless steel member is prepared by in-situ addition of MnN laser additive; the specific weight ratio is that 8% -13% of MnN is added in S12791, 9% -13% of MnN is added in S13091; the laser additive manufacturing and forming process is a powder spreading type or a powder feeding type process, wherein the powder spreading type is a laser selective melting process, and the powder feeding type is a laser melting deposition process; S12791, S13091 and MnN powder have particle sizes ranging from 20 to 100um, the laser selective melting process selects powder with particle sizes ranging from 20 to 50um, and the laser melting deposition process selects powder with particle sizes ranging from 50 to 100 um.

Description

Preparation method of high-nitrogen nickel-free austenitic stainless steel member Technical Field A preparation method of a high-nitrogen nickel-free austenitic stainless steel component, in particular relates to a high-nitrogen nickel-free austenitic stainless steel component proportioning design and a laser additive manufacturing preparation process of the high-nitrogen nickel-free austenitic stainless steel component, and belongs to the field of additive manufacturing. Background Austenitic stainless steel is a stainless steel having an austenitic structure at normal temperature, and is the most widely used structural engineering alloy due to its excellent mechanical properties and corrosion resistance. Austenitic stainless steels generally use Ni (content about 8% -25%) as the austenite forming and stabilizing element, and their austenite forming ability can be predicted by the chromium-nickel equivalent ratio Cr eq/Nieq (Cr eq=%Cr+1.5×%Si+%Mo,Nieq =% ni+30× (% c+% N) +0.5×% Mn), where Cr eq/Nieq <1.25 gives a fully austenitic structure. However, ni is an important strategic resource in our country, and has high cost and poor biocompatibility, and it is becoming increasingly important how to obtain austenitic stainless steel by using other elements to replace Ni. From the nickel equivalent calculation formula, the austenitic forming ability of N is 30 times that of Ni, and is a strong austenitic forming and stabilizing element, and nitrogen acts as interstitial atoms to perform solid solution strengthening and fine crystal strengthening. Therefore, the high-nitrogen nickel-saving austenitic stainless steel with the advantages of low cost, high strength, high toughness, high corrosion resistance, excellent biocompatibility and the like is an ideal substitute for the traditional Cr-Ni stainless steel, and has good application prospect in the fields of national defense and military industry, energy chemical industry, transportation, medical appliances and the like. The mass fraction of nitrogen in high nitrogen nickel free austenitic stainless steel exceeds 0.4%, however the equilibrium solubility of nitrogen in the steel phases is low (2.8 wt% for gamma austenitic phase, 0.04 wt% for L liquid phase, 0.0128 wt% for delta ferritic phase). Therefore, the prior high-nitrogen nickel-free austenitic stainless steel is generally prepared by adopting modes such as high-pressure smelting, the conventional high-pressure smelting process is relatively complex, and the high-strength and high-hardness of the high-nitrogen nickel-free austenitic stainless steel are difficult to process into complex components by the conventional method, so that the development and the application of the high-nitrogen nickel-free austenitic stainless steel are limited. As an emerging manufacturing technology, laser additive manufacturing can realize rapid manufacturing of three-dimensional complex structural parts in a layer-by-layer accumulation mode, and is one of the most potential research directions for preparing high-nitrogen nickel-free austenitic stainless steel components. However, the prior art is difficult to prepare the high-nitrogen nickel-saving austenitic stainless steel powder with higher nitrogen content for laser additive manufacturing through low cost, and various standard brands of high-nitrogen nickel-saving austenitic stainless steel commercial powder are temporarily absent in the market. Therefore, how to obtain the high-nitrogen-content stainless steel powder is a precondition for laser additive manufacturing of high-nitrogen nickel-free austenitic stainless steel and a key for successfully preparing high-nitrogen nickel-free austenitic stainless steel components. The preparation of the high-nitrogen nickel-free austenitic stainless steel by adding nitride into the existing nickel-free stainless steel (ferrite stainless steel, martensitic stainless steel and heat-resistant steel) with national standard marks is an effective path. However, the content of C, si, mn, P, S, cr, mo, al, ti and other elements in stainless steel has an important effect on the formation of austenite phase, chromium-nickel equivalent, nitrogen solubility, carbide and the like, how to select proper grades in various nickel-free stainless steels, and what kind of nitrides are selected and how to determine the addition ratio are important. Disclosure of Invention The invention aims to provide a preparation method of a high-nitrogen nickel-free austenitic stainless steel member, which aims to solve the problems that the traditional preparation process of the existing high-nitrogen nickel-free austenitic stainless steel member is complex, the cost is high, the period is long and the like, and the powder raw materials for laser additive manufacturing are difficult to obtain and the like, and the development of special high-nitrogen nickel-free austenitic stainless steel components is immature and the like. In order to solve the problems, a prep