Experimental study of the influence of material, size, angle and spraying pressure of sand on the erosive behavior of AISI H13 steel in core molding process

The erosion of core boxes caused due to sand shooting in core molding process is one of major concerns of foundry industry. This paper study the effect of impact angle, blasting pressure of sand particles and the type of heat treatment on erosion of AISI H13 tool steel that is widely used in producing core dies. The workpiece material used in this study was AISI H13 tool steel. The tests were performed on a sand shooting machine which simulated the core molding process experimentally. The results show that the erosion of samples is a function of impact angle, shooting pressure and heat treatment as the erosion increases with the increase in shooting pressure. Among the heat treated samples the highest level of erosion has been observed for quench tempered, martempered, carburized and nitrated samples respectively. The Scanning Electron Microscopy (SEM) of surface of templates show that by changing the impact angle from 20 to 90 degrees, the material removal type changes from cutting mechanism to fracture. Further analyses revealed that with increase in shooting pressure from a threshold value abrasive particles trap on the surface of the samples that makes the Mechanically Mixed Layer (MML) and so that decreases the erosion rate. Results express that silica sand causes more erosion than chromite sand; also the erosion increases with increase in size of sand particles.