A thermodynamic calculation method for optimizing the high temperature brazing process of high nitrogen steel

Abstract

A thermodynamic calculation method for optimizing the high temperature brazing process of high nitrogen steel. The invention belongs to the field of high-nitrogen austenitic stainless steel brazing. The invention aims to study the influence of high-nitrogen and ultra-high-nitrogen stainless steel on the relative material properties of the precipitation in the brazing process, so as to optimize the high-nitrogen steel brazing process. The method of the present invention uses the thermodynamic calculation software Jmat Pro to calculate the equilibrium phase diagram of the high-nitrogen steel precipitation phase based on the CALPHAD calculation method, thereby obtaining the precipitation temperature range of the high-nitrogen steel precipitation phase, and then according to the nucleation kinetic equation Johnson- Mehl-Arvami calculates the isothermal cooling transition curve and continuous cooling transition curve of high nitrogen steel, and finally obtains the sensitive precipitation temperature range and incubation period of high nitrogen steel precipitates from the isothermal cooling transition curve, and avoids brazing in the above temperature range. The invention provides a stable calculation method for determining the optimum brazing parameters of the high-nitrogen steel high-temperature brazing process.

Description

technical field [0001] The invention belongs to the field of high-nitrogen austenitic stainless steel brazing, and in particular relates to a thermodynamic calculation method for optimizing a high-nitrogen steel high-temperature brazing process. Background technique [0002] Regarding the definition of high-nitrogen steel, it is generally believed that the steel with nitrogen content greater than 0.4% in the austenite matrix (mass percentage) or greater than 0.08% in the ferrite matrix is ​​called high-nitrogen steel. Due to the shortage of resources, many scholars have proposed to use nitrogen instead of nickel to austenitize the structure. In austenite, nitrogen is easier to dissolve than carbon, and can reduce the precipitation of carbides, improve the strength and durability of steel. corrosion. With the development of high-nitrogen steel, some outstanding advantages of this steel type have been found, such as high strength, good toughness, good process performance and ...

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Problems solved by technology

The precipitation of carbonitrides in steel will seriously affect the performance of the material, not only will significantly reduce the plastic toughness of the material, but also affect its own resistance to pitting corrosion and intergranular corrosion

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