Study of defects in directed energy deposited Vanadis 4 Extra tool steel

A cold work tool steel with varied number of layers was deposited on a substrate hot for hard-facing by directed energy deposition technique. This study deals the defects and microstructure in as-cladded steels. Defects, including pores cracks, were found zone, which increased building height or deposited. Large irregular mainly located at lower regions layers. The formation this type attributed to segregation alloy elements pore surface insufficient heat input. Non-equilibrium eutectic characteristic feature adjacent pores. Cracking, other hand, tended occur upper part Two important contributing factors identified cracking. first one microstructural gradient, modified from fine cellular dendrite columnar when moving bottom top layer. Second, exhibited relatively large temperature range solidification, as simulated Thermocalc software, leading high sensitivity