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

Abstract

The invention belongs to the field of material surface treatment, and particularly discloses a method for achieving steel surface rapid high-nitrogen tempering through the nitrogen arc and nitride in-situ metallurgy nitrogen increment technology. The method comprises the steps that nitride alloy powder and iron powder are mixed to be uniform through a bi-pass coaxial spiral gas powder cover, heated through a nitrogen arc and fed to the surface of a steel base material to be treated, meanwhile, nitride alloy powder, iron powder and some of the base material are heated and molten through the nitrogen arc, a molten pool is stirred through electric arc electromagnetic stirring and welding gun swing, alloy elements in the molten pool and molten base material are sufficiently molten and mixed, the molten pool is cooled and solidified, and therefore a high-nitrogen steel layer can be formed on the steel surface. The treated high-nitrogen steel layer is high in nitrogen content which is far larger than the largest nitrogen content obtained through conventional surface nitrogen increment treatment. The high-nitrogen steel layer with different ingredients and properties can be obtained through real-time adjustment in the nitrogen increment process.

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...

AI Technical Summary

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

Images