Performance requirements of tungsten carbide pot materials

       Performance requirements of tungsten carbide pot material:

(1) Bite resistance.

The bite resistance is actually the resistance to "cold welding". Generally, under dry friction conditions, the sample of the tested die steel and the material with seizure tendency (such as austenitic steel) are subjected to a constant-speed dual friction movement, and the load is gradually increased at a certain speed. At this time, the torque is also Increase accordingly. When the load increases to a certain critical value, the torque suddenly increases sharply, which means that seizure has occurred, and this load is called "occlusion critical load". The higher the critical bite load, the stronger the bite resistance. Table 2-2 shows the critical occlusal loads of several die steels and their surface strengthening processes.

(2) Resistance to softening by heat.

The thermal softening resistance reflects the influence of the warm opening of the cold work die steel under load on the hardness, deformation resistance and wear resistance. There are two main indicators that characterize the softening resistance of cold work die steel under heating: softening temperature (T) and secondary hardening hardness (CHRC). See Table 2-3.

The heating softening temperature is the highest tempering temperature that maintains a hardness of 58 HRC. It reflects that the steel grade can maintain the limit temperature rise allowed by the commonly used working hardness of the mold under the condition of conventional heat treatment. The secondary hardening hardness reflects whether the steel can accept surface strengthening treatment (such as nitriding, liquid nitrocarburizing, ion nitriding, etc.) after heat treatment. For high strength and toughness steel grades, the secondary hardening hardness should not be lower than 60 HRC; for high load-bearing steel grades, the secondary hardening hardness should not be lower than 62 HRC.