A device for increasing nitrogen on steel surface by using nitrogen arc and nitride in-situ metallurgy

Abstract

The invention belongs to the field of surface treatment of materials, and particularly relates to a device and method for realizing nitrogen increment on the surface of steel through nitrogen arc and nitride in-situ metallurgy. Nitride alloy powder and iron powder are mixed evenly through a two-way coaxial spiral air powder cover, heated through a nitrogen arc and then conveyed onto the surface of a steel base material to be treated. Meanwhile, the nitride alloy powder, the iron powder and part of the base material are heated and smelted through the nitrogen arc; a molten pool is stirred through electromagnetic stirring with an electric arc and swinging of a welding gun so that alloy elements in the molten pool and the molten base material are fully smelted and mixed. A high-nitrogen steel layer is formed on the surface of the steel after the molten pool is cooled and solidified. The nitrogen content of the high-nitrogen steel layer obtained after treatment is high and is far lager than the maximum nitrogen content obtained through a common surface nitrogen increment treatment method. Through real-time adjustment of the nitrogen increment process, high-nitrogen steel layers with different components and properties can be obtained.

Description

technical field [0001] The invention relates to the field of material surface treatment, in particular to a device and method for realizing rapid high-nitrogen tempering of steel surface by using nitrogen arc and nitride in-situ metallurgical nitrogen addition. Background technique [0002] Common surface nitriding methods include gas nitriding and ion nitriding. [0003] Gas nitriding can adopt general nitriding method (ie isothermal nitriding) or multi-stage (two-stage, three-stage) nitriding method. The former is that the nitriding temperature and ammonia decomposition rate remain unchanged throughout the nitriding process. The temperature is generally between 480-520°C, the decomposition rate of ammonia gas is 15-30%, and the holding time is nearly 80 hours. This process is suitable for parts with shallow penetration, strict distortion requirements, and high hardness requirements, but the processing time is too long. Multi-stage nitriding is to use different temperatu...

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Problems solved by technology

Coat the prepared slurry on the surface of the part and dry it, then use a nitrogen arc to weld it. The slurry does not contain nitrogen elements, and the effect of increasing nitrogen by nitrogen arc alone is not obvious, and it takes time to dry. If it is not completely dried, it may hydrogen induced cracking

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