Cold Extrusion Punch for Micron Tungsten Carbide Reinforcement Layer

Stamping die is an indispensable technological equipment for stamping production and a technology-intensive product. The quality, production efficiency and production cost of stamping parts are directly related to die design and precision quality of die parts.

Tungsten carbide has many advantages, such as high specific stiffness, specific modulus, low thermal expansion coefficient, good thermal stability, wear resistance, dimensional stability and good wettability with iron and steel materials. Using tungsten carbide as reinforcer, cold extrusion punch with tungsten carbide reinforced layer can be prepared, which can greatly improve the surface hardness and strength of cold extrusion punch. At the same time, the toughness of cold extrusion punch can be improved by using the high bonding strength between in-situ reactive tungsten carbide reinforced layer and high-speed steel matrix.

The cold extrusion punch for micron tungsten carbide reinforced layer comprises the following steps:

Step 1: Surface treatment was carried out on the cold extrusion punch body of high speed steel to obtain the surface treated cold extrusion punch body of high speed steel.

Step 2: Laser punching machine is used to punch the surface treated high-speed steel cold extrusion punch body obtained in step 1, then pickling is carried out, then water is washed to neutral, and finally ultrasonic cleaning is carried out to obtain the washed high-speed steel cold extrusion punch body with depressed tube body.

Step 3: The high-speed steel cold extrusion punch body with hollow tube body obtained in step 2 is placed in a vacuum carburizing furnace for carburizing at a certain temperature and holding for a certain time to obtain a composite with micron tungsten carbide reinforcement layer.

Step 4: A high speed steel cold extrusion punch with micron tungsten carbide reinforcing layer was obtained by annealing, step quenching and three times low temperature tempering of the composite obtained in step 3.

The surface strength and hardness of existing Cold Extrusion Punches for high speed steel were improved by controlling the carburizing process parameters and laser drilling parameters, and the volume fraction, distribution and morphology of WC reinforced phase were controlled. The heat resistance and wear resistance of composites were improved. Meanwhile, the in-situ reaction between WC reinforced layer and matrix of high speed steel was used. High bonding strength can improve the toughness of cold extrusion punch, solve the problems of permanent deformation, fracture and breakage of high speed steel cold extrusion punch, and the preparation method is simple and easy to implement.

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