Hydrogen Embrittlement Characteristics of a Die-Casting Die after a High-Pressure Die-Casting Operation

In this work, the failure characteristics of a die-casting die manufactured from conventional hot-worked steel (SKD61) were investigated experimentally. A die with heat-checking failure on its cavity due to high-pressure die casting was employed. Apparently, the microstructural characteristics of the die around the regions exhibiting heat checking were unaltered. However, the hardness values decreased slightly because of the die heating via the injection of molten aluminum alloy, which is the tempering-like effect. Hydrogen was detected in the die around the regions with heat checking, which can slightly reduce the tensile fracture strain, i.e., hydrogen embrittlement (HE). The extent of HE was sensitive to the loading speed, particularly to a low loading speed. When heated to 450 degrees C, hydrogen gas was detected in a commercial die lubricant, which may lead to hydrogen infiltration in the die. This paper discusses the details pertaining to hydrogen penetration and die failure mechanisms.