Vacuum Brazing of Tungsten Carbide to 45# Steel

Tungsten carbide and 45# carbon steel are widely used together in tooling and wear-resistant components, combining extreme hardness with good structural toughness. However, due to the large difference in physical and metallurgical properties, such as thermal expansion coefficient and wettability, reliable joining requires a controlled and precise process. Vacuum brazing is one of the most effective solutions for achieving a high-quality bond between these two materials.

Physical properties: Tungsten carbide is significantly harder and denser (approx. 15.63 g/cm3) than 45# steel.

The sample shown in the figure consists of a tungsten carbide part brazed to a 45# steel base using a Normantherm vacuum brazing furnace. Before brazing, both parts are precisely machined and cleaned to ensure proper joint fit and surface condition. A suitable active or silver-based brazing alloy is applied at the joint interface. The brazing cycle is carried out under high vacuum, typically better than 10⁻³ Pa, effectively preventing oxidation and promoting excellent wettability of the filler metal on both tungsten carbide and steel surfaces.

During heating, the furnace provides uniform temperature distribution and accurate control of heating rate, brazing temperature, and holding time. This minimizes thermal stress and avoids damage to the brittle carbide phase. The resulting joint shows dense microstructure, strong metallurgical bonding, and good shear strength, while maintaining the original properties of both base materials.

Normantherm vacuum brazing furnace technology ensures stable process control, consistent joint quality, and reliable finished products suitable for both prototype development and batch production.