氧乙炔火焰粉末喷焊及焊后热处理对基体,合金层组织结构与硬度的影响

本文采用光学显微镜、X射线衍射和硬度试验等方法,研究了氧乙炔火焰粉末喷焊及焊后热处理对40CrNiMo基体、合金层组织和硬度影响的规律。结果表明,火焰粉末喷焊使基体组织粗大,原淬火钢的回火索氏体,变成粗大的多相混合组织,硬度大大降低。喷焊后进行重新加热淬火,油冷到基体材料Ms点以下某一温度范围立即回火的热处理,使基体组织又得到了细化,硬度亦得到了恢复;而合金焊层没有受到影响,组织结构和硬度没改变。

THE EFFECT OF OXYACETYLENG FLAME POWDER SPRAY WELD AND POST-WELD HEAT TREATMENT ON STRUCTURE AND HARDNESS OF BASE MATERIAL AND ALLOY LAYER

This paper describes, by means of optical microscope, X-ray diffraction andhardness test, the effect of oxyacetylene flame powder spray weld and post--weldheat treatment on the structure and hardness of the base material or hardenedsteel 40CrNiMo and alloy layer. The test results showed that the oxyacetyleneflame powder spray weld made the structure of the base material corse, or madethe tempering sorbite of the original steel become the corse pearlite and blockferrite decreasing greatly the hardness. After the post-weld heat treatment con-sisting of heating, quenching, oilcooling and tempering was formed,the structu-re of the base material became fine again and the oyiginal hardness of the basematerial regained while the structure and hardness of the alloy layer did notchange.