Study on microstructure and properties between alloy steel and powder steel via hot isostatic pressing diffusion bonding

PM23 powder steel and H13 hot working die steel and 9Cr2Mo cold working die steel bimetallic composite components were successfully prepared by hot isostatic pressing powder-solid diffusion bonding process. The interfacial behavior of H13-PM23 and 9Cr2Mo-PM23 bimetals was studied by SEM and EBSD techniques; the mechanical properties of the two bimetals were evaluated by universal testing machine. The results indicated that the element diffusion occurred in the interfacial bonding region, and an obvious decarburized layer was observed in the 9Cr2Mo-PM23 bimetals, whose surface was enriched with small rod-like and dot-like MC and M6C carbides. The tensile strength of H13-PM23 and 9Cr2Mo-PM23 bimetals could reach 882 MPa and 772 MPa, respectively, and the fracture occurred exclusively on the side of PM23 powder steel, which could achieve good metallurgical bonding and stable connection. This study provides potential application guidance for enhancing efficiency while reducing costs in composite bimetallic spinning rollers.