Effect of WC based coatings on the wear of CK45 sheet metal forming dies

DIN 1.2379 tool steel has a wide range of applications in die manufacturing industry owing to its high wear resistance. However, CK45 steel is cheaper but extensive wear occurs on CK45 die and sheet metal surfaces, which were attempted to be solved using a hard phase coating. An insert on a die was designed and manufactured for the area where the wear is expected the most. Electro-spark deposition (ESD) coating layer was formed with two separate layers of WC (tungsten carbide) and WC+SS (tungsten carbide and stainless steel) on die surfaces using optimum parameters to obtain wear resistant surfaces as a means of controlling the friction between sheet metal-die surfaces. After 500 pressings, insert surfaces were characterised by optical and scanning electron microscopy. The results showed that defects on sheet metals were reduced following the application of hard phase ESD coating. The microhardness values of ESD coatings were higher than that of CK45 base metal and similar to hardened DIN 1.2379 steel.