Die soldering is challenging issue on die life and casting quality in High Pressure Die Casting (HPDC) Industry. It
increases die down time which causes increasing production cost per piece. Die soldering can be tackled by surface
heat treatment operations like gas nitriding and other PVD coatings. Used and scraped die is selected from the die
casting industry for investigation of die soldering issue. Chemical distribution of elements and surface condition of
affected die soldering zone is investigated. The study reveals that, there are abundant micro cracks, micro holes and
micro cavities at soldering portion. The radius of micro holes is about 0.25 μm and the radius of macro holes is
about 8μm. The die inserts are made up of H13 die steel and LM24 Aluminum alloy is used for casting operation. At
the die soldering cross section region, distribution of aluminum and die soldering mechanism and its causes studied.
The die soldering mechanism is classified as chemical, physical, mechanical and mixed soldering. The soldering
phenomena have been researched based on die temperature and its chemistry, metal temperature and its chemistry,
injection pressure and its velocity, and die surface roughness. The spread and formation of die soldering on used and
scraped die is also discussed in this article.