The relationship between cold heading and mold

Cold heading processing has high requirements on the mold. During cold heading processing, the blank is subjected to three-way compressive stress in the mold, which significantly increases the deformation resistance, which makes the stress on the mold much larger than that of the general stamping die. When cold extruding steel, the stress on the mold often reaches 2000MPa～ 2500MPa.

In addition to high strength, the mold also needs to have sufficient impact toughness and wear resistance. In addition, the strong plastic deformation of the metal blank in the mold will increase the mold temperature to about 250°C to 300°C. Therefore, the mold material needs a certain tempering stability. Due to the above conditions, the life of cold extrusion dies is much lower than that of stamping dies.

1. Large tonnage presses are required. Due to the large deformation resistance of the blank during cold extrusion, a press of hundreds or even thousands of tons is required.

2. Due to the high cost of cold heading molds, it is generally only suitable for mass-produced parts. The minimum batch of cold heading processing is 50,000 to 100,000 pieces.

3. The blank needs to be surface treated before extrusion.

4. Not suitable for processing high-strength materials.

5. The plasticity and impact toughness of cold heading processing become poor, and the residual stress of the parts is large, which will cause the deformation of the parts and the reduction of corrosion resistance.