ANALYSIS OF THERMAL CRACKS ON DIE CASTING DIES

The aim of this research was to analyse the aluminum alloy die casting die failures with the aim of prolonging in-service die life. An extensive analysis of thermal fatigue cracks in aluminium alloy die casting was performed. An immersion test apparatus was developed that enables the simulation of conditions during aluminum alloy die casting and the controlled thermal fatigue testing of materials. Specimens of the AISI H13 tool steel were differently heat treated. On the edges of some specimens, the maraging steel was gas tungsten arc (GTA) weld cladded. These samples were tested in as-welded and in optimally aged condition. After completion of a particular number of cycles, the specimen edge surface was examined visually. The specimens were then cut and examined with light and scanning electron microscopy (SEM). The energy-dispersive X-ray spectroscopy (EDS) mapping of areas around the cracks was performed, also, and the number and length of thermal fatigue cracks were assessed and Vickers hardness profiles were determined. The results confirmed the good thermal fatigue resistance of the properly hardened 1113 steel. The surface cracks growth is accelerated by surface oxidation.