Requirements for high precision die fittings
1. resistance to cold and hot fatigue
Some moulds are in the state of repeated heating and cooling in the working process, making the surface of the cavity under the action of tension and stress, causing surface cracking and peeling, increasing friction, hindering the plastic deformation and reducing the size accuracy, resulting in the failure of the mold. Cold and hot fatigue is one of the main forms of failure of hot working dies, and the fittings for Dongguan precision molds should have higher thermal and fatigue resistance.
2. strong toughness
Most of the working conditions of precision die parts in Dongguan are very bad, some of them often suffer large impact load, resulting in brittle fracture. In order to prevent the die parts from breaking suddenly at work, the mold should have higher strength and toughness.
The toughness of the mold depends mainly on the carbon content, grain size and microstructure of the material.
3. high temperature performance
When the working temperature of the die is higher, the hardness and strength decrease, resulting in early wear or plastic deformation of the die. Therefore, the mold material should have higher resistance to tempering to ensure that the mold has higher hardness and strength at working temperature.
4. corrosion resistance
Some moulds, such as plastic moulds in the work, because of the existence of chlorine, fluorine and other elements in the plastic, decomposed and precipitated HCI, HF and other strong erosive gases after heating, eroding the mold cavity surface, increasing the surface roughness and aggravating the wear failure.
5. fatigue fracture properties
During the working process of Dongguan precision die parts, fatigue fracture is often caused by the long-term effect of cyclic stress. Its form is small energy, multiple impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture.
The fatigue fracture properties of the die mainly depend on its strength, toughness, hardness, and the content of inclusions in the material.