Wear resistance and impact resistance of hardfacing alloys: Laser cladding vs. hot isostatic pressing (HIP)

Laser cladding technology has great application potentials in the die, mold and tool industries. This study evaluated and compared laser clad materials with HIP made tool steels and with a conventionally made cold work tool steel (D2) through wear and impact tests. High carbon high vanadium tool steel powders produced via gas atomization were used as hardfacing materials in the laser cladding process. Test results indicate that both laser clad and HIP materials are superior to D2 tool steel in terms of wear resistance. Compared to HIP tool steels, laser clad materials are slightly less resistant to abrasive wear but their impact resistance is 3-4 times higher. Therefore laser clad materials and structures are more favorable in the die stamping, cutting and forming operations. Vanadium carbides in HIP tool steels are not wetted by matrix as well as those in laser clad layers. Secondary cracks were found on the boundaries between VC and matrix in HIP steel, while some VC fractures were observed in the clad layers. This explains why laser clad materials have better impact resistance than HIP tool steels. In addition, the cellular microstructure and retained austenite generated in the laser cladding process also improves a material’s ductility. This research delivers an important and valuable message to industry that laser clad materials and structures can perform better than the conventionally made tool steels and HIP made PM parts.