1. Wear resistance

When the blank is plastically denatured in the mold cavity, it will flow and slide along the surface of the mold cavity, resulting in severe friction between the surface of the mold cavity and the blank, thus leading to the failure of the mold 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 wear resistance. In general, the higher the hardness of mold parts, the smaller the wear amount, and the better the wear resistance. In addition, the wear resistance is also related to the type, quantity, morphology, size and distribution of carbides in the material.

2. Strength and toughness

Most of the working conditions of the dies are very bad, and some of them often bear large impact loads, resulting in brittle fracture. In order to prevent sudden brittle fracture of die parts during working, 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 low 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, leading to early wear or plastic deformation of the die and failure. Therefore, the mold material should have high tempering resistance stability to ensure that the mold has high hardness and strength under the working temperature.

5. Cold and hot fatigue resistance

Some molds are in the state of repeated heating and cooling during the working process, so that the surface of the mold cavity is subject to tensile and pressure stress, causing surface cracking and peeling, increasing friction, hindering plastic deformation, reducing dimensional accuracy, and leading to mold failure. Cold and hot fatigue is one of the main forms of failure of hot working dies, which should have high cold and hot fatigue resistance.

6. Corrosion resistance

When some molds, such as plastic molds, are working, due to the presence of chlorine, fluorine and other elements in the plastic, strong corrosive gases such as HCI and HF will be decomposed after heating, which will corrode the surface of the mold cavity, increase its surface roughness and aggravate wear failure.