Correlation between micro-blasted steel surface roughness and joining strength in injection molded direct joining

抄録

Steel-polymer direct joining is extremely significant for the lightweight design of vehicles. Injection molded direct joining (IMDJ) is a promising direct joining method, which is a combination of metal surface treatment and insert molding. Considering the cost, productivity, and impact on the environment, micro-blasting is an excellent surface treatment method for IMDJ. The steel-polymer joining strength of IMDJ is usually obtained by tensile shear test, which will break the joining. However, a non-destructive strength evaluation method is meaningful to ensure the joining quality in practical application. In this study, the correlation between the blasted steel surface roughness and the joining strength was investigated to be able to estimate the joining quality without breaking it. The correlation coefficient of different evaluation indicators of surface texture and joining strength were calculated. The average absolute slope of the profile Rda has the strongest correlation with the joining strength, the correlation coefficient reaches 0.98. This result shows that we can have a relatively accurate prediction of the joining strength before the injection molding.