退火热处理对高速电弧喷涂碳钢涂层组织性能的影响

采用高速电弧喷涂技术制备高碳钢涂层,并分别进行450、550和650℃保温2h的退火热处理,研究退火工艺对涂层的组织结构、相成分、残余应力及硬度的影响规律。结果表明,除了氧化物之外,高碳钢涂层在热处理前主要含有马氏体组织,450℃退火后出现了粒状渗碳体+铁素体特征的组织,550和650℃退火之后呈现块状特征的组织,且明显粗大;退火处理后涂层中的拉应力有减小的趋势;涂层硬度随着加热温度的升高而降低。因此,合适的热处理工艺可以有效地控制碳钢喷涂层的组织性能。

Effect of annealing treatment on microstructure and properties of high velocity electric arc sprayed steel coating

A type of high carbon steel coating on 45 steel was prepared by electric arc spraying process, and then was annealed at 450,550 and 650 ℃ for 2 h, respectively.The effects of annealing temperature on microstructure, phasea, residual stress and microhardness of the coatings were investigated by means of optical microacope, SEM, XRD and hardness test.Besides oxides, martensite is observed in the as-sprayed coating.After annealing at 450 ℃ for 2 h, the microstructure of granular cementite and ferrite forms in the coating, and after annealing at 550 and 650 ℃.the coatings exhibit coarse block-like microstructure.Tensile residual stress and mircrohardness of the coating decreases with the increase of annealing temperature.It is concluded that microstructure and mechanical properties of the coating can be controlled by proper heat treatment process.