Process flow of tungsten carbide products wear-resistant hardfacing

Tungsten Carbide Brazing: Typically used for welding small-diameter tungsten carbide products or rods, usually joining tungsten carbide to high-speed steel or tungsten carbide to tungsten carbide. This process utilizes eddy current heating by generating a high-frequency alternating magnetic field around the tungsten carbide rod, creating alternating current and high resistive heat at the weld seam to melt the solder and facilitate welding. Due to the skin effect of alternating current, the current concentrates on the rod’s periphery, with lower heat in the middle, making it difficult to melt the solder and resulting in defects such as sand holes and pores, leading to low welding strength. Therefore, it is only applicable to welding small tools and punch pins with diameters of φ6 or less.

Preparation Stage

1. Clearly define the specific requirements for hardfacing the tungsten carbide products and select suitable hardfacing methods and welding parameters.
2. Choose appropriate tungsten carbide welding rod as hardfacing material, ensuring the welding rod quality meets standards.
3. Thoroughly remove oil stains, rust, and cracks from the workpiece surface to ensure welding quality. For workpieces with existing cracks and delamination, stress-relief annealing is required to eliminate the impact of internal stress on tungsten carbide products hardfacing.
4. Clean any debris from the base material surface before welding.
5. Use a smaller current to prevent arc cracking.
6. For thicker weld layers, hardfacing can be repeated.

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Welding Stage

Using an automatic alloy material feeder, directly hardface tungsten carbide (WC) particles onto the workpiece surface. Tungsten carbide particles do not settle at the bottom of the hardfacing layer but are directly fused onto the workpiece surface. During welding, direct current is recommended, and a smaller current should be used. Since the coating of tungsten carbide welding rod is thick, heating can cause small pieces of the coating to fall off, so special attention is required for current selection and control. Through mechanized operation, tungsten carbide alloy particles can be evenly distributed from top to bottom in the wear-resistant hardfacing layer, enhancing wear resistance after the temperature cools.

Post-Processing

Inspect the hardfaced workpiece to ensure the hardfacing layer is uniform and defect-free. Perform subsequent processing as needed, such as grinding and polishing, to meet the workpiece’s usage requirements. The tungsten carbide welding rod hardfacing process, through this series of steps, can form a hardfacing layer with high hardness and wear resistance on the workpiece surface, thereby improving the workpiece’s durability and service life.