A method of nitrogen arc in-situ metallurgy pre-laying nitride to realize nitrogen increase on steel surface

Abstract

The invention relates to the field of material surface treatment, in particular to a method for achieving nitrogen increment on the steel surface through nitrogen arc in-site metallurgy pre-laid nitride. The method comprises the steps that mixed nitride alloy powder is laid on the surface of steel base metal to be treated, then the nitride alloy powder and part of the base metal are heated and melted through nitrogen arcs, a molten pool is stirred through electromagnetic stirring of electric arcs and swinging of a welding gun, alloy elements in the nitride alloy powder and the molten base metal are sufficiently melted and mixed, and a high-nitrogen steel layer can be formed on the steel surface after the molten pool is cooled and solidified. According to the method, the thickness of the prepared high-nitrogen steel layer can reach a few millimeters or even reaches the centimeter grade according to requirements, ultrahigh nitrogen content can be obtained through the high-nitrogen steel layer, and the ultrahigh nitrogen content is much larger than the maximum nitrogen content which is obtained through conventional surface nitrogen increment treatment.

Description

technical field [0001] The invention relates to a material surface treatment technology, specifically a method for increasing nitrogen on steel surfaces by using nitrogen arc in-situ metallurgy to pre-lay nitrides, and is suitable for high-strength corrosion-resistant treatment of surfaces such as low-carbon steel, low-alloy steel, and stainless steel. 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 requiremen...

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

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