Investigation of microstructural and mechanical properties of dissimilar WC–8 %Co/AISI 1006 steel joints brazed using tube, induction, and infrared furnaces

Integrating tungsten carbide (WC–8Co) with steel is a pivotal aspect of cutting tool manufacturing, as monolithic carbide tools are inherently brittle and cannot be fabricated as a single component. To enhance toughness and resistance to dynamic stresses, WC is brazed to steels with greater ductility. Given WC's high melting temperature, conventional welding methods are ineffective, making brazing one of the most suitable techniques for joining dissimilar materials. This study aimed to optimize the brazing process to minimize the loss of WC hardness, as a reduction in hardness compromises tool efficiency and lifespan. In this research, WC–8Co was brazed to AISI 1006 steel using a silver-based filler (BAg22) through tube, induction, and infrared furnaces at temperatures of 800 °C, 850 °C, and 900 °C under vacuum conditions, with induction powers set at 10 and 15 kW. The microstructural and mechanical properties were assessed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), microhardness testing, and shear testing. The initial hardness of WC was measured at 2202 HV, with decreases of 1.8%, 10%, and 22% observed for the induction, infrared, and tube furnaces, respectively. The shear strength was highest for the induction furnace (294 MPa), followed by the infrared furnace (268 MPa) and the tube furnace (202 MPa). OM/SEM/EDS analyses revealed a silver- and copper-rich eutectic structure, while elevated temperatures enhanced filler wettability and diffusion, resulting in uniform, defect-free joints. These findings yield quantitative insights for optimizing the brazing of WC–steel joints, facilitating the manufacturing of high-performance cutting tools.