1. Wear resistance
When the blank is plastic deformed in the mold cavity, it flows and slides along the surface of the cavity, resulting in severe friction between the surface and the billet, resulting in failure of the die due to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of the mold.
Hardness is the main factor affecting the wear resistance. In general, the higher the hardness of the mold parts, the smaller the wear and the better the wear resistance. In addition, the wear resistance is also related to the type, quantity, shape, size and distribution of carbides in the material.
2. strong toughness
Most of the working conditions of the die are very bad, and some often bear large impact load, which leads to brittle fracture. In order to prevent the die parts from breaking suddenly at work, the mold should have high strength and toughness.
The toughness of the mold mainly depends on the carbon content, grain size and microstructure of the material.
3. fatigue fracture properties
In the working process of the die, the fatigue fracture is often caused by the long-term action of cyclic stress. Its form has small energy multiple impact fatigue fracture, tensile fatigue fracture contact fatigue fracture and bending fatigue fracture.
The fatigue and fracture properties of the mold mainly depend on its strength, toughness, hardness, and the content of inclusions in the material.
4. high temperature performance
When the working temperature of the mold is higher, the hardness and strength will decrease, which causes the die early wear or plastic deformation to fail. Therefore, the mold material should have high anti tempering stability, so as to ensure that the mould has high hardness and strength at working temperature.
5. resistance to cold and hot fatigue
Some dies are in the state of repeated heating and cooling during the working process, causing the surface tension and pressure to act on the cavity surface, causing the surface cracking and spalling, increasing the friction force, hindering the plastic deformation, reducing the dimensional accuracy, resulting in the failure of the die. Cold and hot fatigue is one of the main forms of failure of hot die, which should have a high resistance to cold and heat fatigue.
6. corrosion resistance
Some molds, such as chlorine, fluorine and other elements in plastic, are decomposed by HCI, HF and other strong corrosive gases, which destroy the surface of mold cavity, increase the surface roughness and intensify wear failure.
