Although there are many kinds of cold deformation molds with different working conditions and different performance requirements, the basic working conditions are similar: that is, they deform the metal in the cold state and bear large shear force, pressure, bending force, impact force and friction force when working.
Processing characteristics of cold deformation die steel
1. High hardness and high strength to ensure that it is not easy to produce a small amount of plastic deformation or damage when bearing high stress.
2. High wear resistance can ensure the dimensional accuracy of the die under high wear conditions, which is more important for drawing dies and cold stamping dies.
3. Sufficient toughness, so that it is not easy to peel off or collapse of working toughness under impact load and dynamic load.
4. Heat treatment deformation should be small. Because most molds have complex cavities and precise accuracy, heat treatment deformation is difficult to be eliminated by grinding. In addition, some cold deformation molds should also have sufficient heat resistance. How to reasonably select the material of cold deformation die and appropriate heat treatment means to improve the service life of die is the most concerned problem in production. As a normal failure of cold deformation die, it should be wear, micro plastic deformation and fatigue failure. However, in actual production, in addition to the grinding loss effect, it is common to see premature failure such as fracture and cracking. As we all know, it is a comprehensive factor that affects the service life of cold deformation dies; The rationality of raw material selection, the internal metallurgical quality of raw materials, the rationality of design and manufacturing process, the use conditions and the technical level of operating workers, etc.
Material selection of cold deformation die steel
1. Working conditions of the mold, including equipment type, processing frequency, processed material, lubrication and environment, etc;
2. The complexity of mold shape and processing procedure;
3. Production batch and technical requirements of products;
4. The difficulty of mold material source and processing conditions. The material cost of large molds often accounts for more than 50% of the mold cost. For molds with complex shape and high accuracy requirements, it is appropriate to choose mold steel with small quenching deformation.
According to the actual use, the commonly used cold deformation die steels include low hardenability steel, low deformation steel, micro deformation steel, high strength steel, high toughness steel and impact resistant cold deformation die steel.