1. Wear resistance
When the blank is plastically denatured in the mold cavity, it flows and slides along the cavity surface, resulting in severe friction between the cavity surface and the blank, resulting in the failure of the mold due to wear. Therefore, the wear resistance of materials is one of the most basic and important properties of molds
Hardness is the main factor affecting wear resistance. In general, the higher the hardness of die 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. Strength and toughness
Most of the working conditions of dies are very bad, and some often bear large impact load, resulting in brittle fracture. In order to prevent sudden brittle fracture of die parts during operation, the die should have high strength and toughness. The toughness of the die mainly depends on the carbon content, grain size and microstructure of the material
3. Fatigue fracture performance
In the process of die working, fatigue fracture is often caused by the long-term action of cyclic stress. Its forms include small energy multiple impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture. The fatigue fracture performance of the die mainly depends on its strength, toughness, hardness and the content of inclusions in the material
4. High temperature performance
When the working temperature of the die is high, the hardness and strength will decrease, resulting in early wear or plastic deformation and failure of the die. The die material shall have high tempering stability to ensure that the die has high hardness and strength at working temperature
5. Cold and hot fatigue resistance
Some molds are in the state of repeated heating and cooling in the working process, so that the surface of the cavity is under the action of tensile and pressure strain stress, resulting in surface cracking and peeling, increasing friction, hindering plastic deformation and reducing dimensional accuracy, resulting in mold failure. Cold and hot fatigue is one of the main forms of hot working die failure. This kind of die should have high cold and hot fatigue resistance
6. Corrosion resistance
When some molds, such as plastic molds, work, due to the presence of chlorine, fluorine and other elements in the plastic, they decompose and precipitate HCI, HF and other strong corrosive gases after heating, eroding the surface of the mold cavity, increasing its surface roughness and aggravating wear failure.