The basic function of cold iron when it is used is to chill the pump valve casting. The chilling effect of cold iron is used to adjust the local or overall solidification process of the casting.
The specific role of pump valve castings
1. Improve the hardness and wear resistance of castings.
2. Control the directional solidification or simultaneous solidification of the casting.
3. Eliminate the local hot section of the casting.
4. Prevent cracks in castings.
5. Reduce the number of risers.
6. Reduce the size of the riser, etc.
Hardness testing of Pump valve castings
1. Rockwell hardness: HRA is mainly used for high hardness test pieces. The hardness and surface hardness of materials above HRC67, such as cemented carbide and nitrided steel, are measured. The measurement range is HRA>70. HRC is mainly used for steel parts (hardness measurement after quenching or tempering, measuring range HRC20~67.
2. Vickers hardness: used to determine the hardness of thin and steel parts, can also be used to determine the hardness of surface hardened parts such as carburizing, cyanidation and nitriding.www.dmgcastings.com