1. Wear resistance When the blank is plastically deform […]
1. Wear resistance
When the blank is plastically deformed in the cavity of Car Parts Mould, it flows and slides along the cavity surface, which causes severe friction between the cavity surface and the blank, which leads to the failure of the mould due to wear. Therefore, the wear resistance of materials is one of the most basic and important properties of car parts mould.
Hardness is the main factor affecting wear resistance. Generally speaking, the higher the hardness, 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 materials.
2. Strength and toughness
Most of the working conditions of car parts mould are very bad, and some of them often bear large impact load, which leads to brittle fracture. In order to prevent the car parts mould from breaking suddenly when working, the mould should have high strength and toughness.
The toughness of car parts mould mainly depends on the carbon content, grain size and microstructure of materials.
3. Fatigue fracture performance
During the working process of car parts mould, fatigue fracture often occurs under 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 car parts mould mainly depends on their strength, toughness, hardness and the content of inclusions in materials.
4. High temperature performance
When the working temperature of car parts mould is higher than that of AG, the hardness and strength will decrease, resulting in early wear or plastic deformation of mould and failure. Because the mould material should have high tempering stability, so as to ensure that the mould has high hardness and strength at working temperature.
5. Cold and hot fatigue resistance
Some car parts mould are heated and cooled repeatedly in the working process, which makes the surface of the cavity become stressed by tension and pressure, causing surface cracking and spalling, increasing friction, hindering plastic deformation and reducing dimensional accuracy, resulting in mould failure.
6. Corrosion resistance
When some car parts mould work, because there are elements such as chlorine and fluorine in plastics, hci, hf and other aggressive gases are decomposed after being heated, which erode the surface of mould cavity, increase its surface roughness and aggravate wear failure.