热镀锌机组碳化钨喷涂工艺辊表面涂层失效分析

Failure Analysis of the WC-coating on CGL Process Roll

本文主要研究了热镀锌机组喷涂碳化钨的工艺辊在使用过程中发生表面喷涂层发生剥落的原因。工艺辊基体材质为45号钢,表面采用超音速喷涂碳化钨涂层,该工艺辊服役不到一年时间,发现辊面中部喷涂层剥落。针对辊面喷涂层剥落问题,进行了喷涂材料的成分分析、涂层的微观分析等。研究发现喷涂前的喷砂工艺非常关键,在喷涂层剥落之处可以发现残留的砂粒。通过涂层断面分析,进一步的证明了在喷涂前的喷砂毛化工序中,没有完全清除残留的砂粒会导致在使用过程中喷涂层的剥落。

The spalling reason of the sprayed WC coating on the roller in the continuous hot-dip galvanizing line(CGL)was studied.The base material of the process roller is 45 steel,and the surface is sprayed with tungsten carbide coatings by High Velocity Oxy-Fuel(HVOF)spraying.After less than one year service,it is found that the spraying layer in the middle of the roller surface peels off.Aiming at the spalling of spray coating on roller surface layer on the roller surface,the composition analysis of the spraying material and the micro analysis of the coating are carried out.The analysis shows that the sandblasting process before spraying is very important.The residual sand particles can be found at the spalling places of the spraying layer.Through the analysis of coating cross section,it is further proved that in the process of sand blasting before spraying,the residual sand particles are not completely removed,which will lead to the peeling off of the spraying layer during the service.