How to select mould material

- Oct 24, 2017-

Condition requirements:

1. Abrasion resistance

When the billet is plastic degeneration in the mold cavity, the surface of the cavity is flowing and sliding, which causes the sharp friction between the cavity surface and the billet, which leads to the 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 that affects wear resistance. In general, the higher the hardness of the die parts, the smaller the wear, the better the wear resistance. In addition, the abrasion resistance is 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, some often bear a large impact load, resulting in brittle fracture. In order to prevent the die parts at work suddenly brittle broken, the mold should have a high strength and toughness.

The toughness of the mould depends mainly on the carbon content, grain size and microstructure of the material.

3. Fatigue Fracture Performance

In the process of the die, under the long-term effect of cyclic stress, it often leads to fatigue fracture. The form has small energy multiple impact fatigue fracture, tensile fatigue fracture contact fatigue fracture and bending fatigue fracture.

The fatigue fracture performance of the die depends mainly 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, it will decrease the hardness and strength, resulting in the early wear of the mould or the plastic deformation. Therefore, the mold material should have a high resistance to tempering stability, in order to ensure that the mold at the operating temperature, with high hardness and strength.

5. Heat and cold fatigue resistance

Some molds in the work process in the state of repeated heating and cooling, so that the surface of the cavity by tension, pressure variable stress effect, causing surface cracking and spalling, increase friction, hinder plastic deformation, reduce the size of precision, resulting in mold failure. Hot and cold fatigue is one of the main forms of the failure of heat-making die, which should have high heat and cold fatigue resistance.

6. Corrosion resistance

Some molds such as plastic mold at work, because of the presence of chlorine, fluorine and other elements of plastic, after the decomposition of the gas, HCI, HF and other strong corrosive gases, erosion mold cavity surface, increase its surface roughness, increase wear failure.