Tungsten heavy alloy as a filler metal for repair welding of dies for high pressure die casting

Abstract

Abstract This paper presents the preliminary test of tungsten heavy alloy as a filler metal for repair welding of high pressure die casting dies. H13 grade hot work tool steel was used as a base material. Multipass gas tungsten arc welding was used to fill a single-V butt joint with tungsten heavy alloy in the form of a welding rod. The microstructure of the weld was examined using scanning electron microscopy and optical microscopy. It was found that tungsten grains are not dissolved completely during welding and areas of fine eutectic were formed during solidification of the weld. The hardness of the weld was measured in three courses across the weld and increased in the heat affected zone while the weld hardness was below 380 HV0.3. Charpy V-notched samples were prepared from the weld. The high content of tungsten grains distributed in the nickel–iron weld matrix resulted in low impact toughness of 5.1 J. Face bend testing of the weld was conducted in order to study weld ductility.