Experimental and numerical analysis of failures on a die insert for high pressure die casting

A comprehensive study of failures on a used insert of a die for high pressure die casting of aluminium alloy AlSi9Cu3Fe was conducted. The analysed insert was made of hot work tool steel Dievar, heat treated and plasma nitrided according to specifications. Before the start of analysis, the insert was subjected to 170,000 die casting cycles. X-ray diffraction, light microscopy, scanning electron microscopy and hardness measurement methods were used for experimental analysis of soldering, corrosion, erosion and thermal fatigue failure modes on the insert. A special procedure, which combines use of commercial software MAGMA5.3 and open source software CalculiX, was developed for numerical calculations of temperature fields on the insert. Experimental and numerical results showed strong dependence between die surface temperatures and die failure modes. Hardness drop, nitride diffusion layer removal and microstructural changes were observed at more thermally affected areas. Surface crack with a thin oxide and thicker soldered layer was identified and analysed.