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Requirements For Mold Material Selection

1. Abrasion resistance

When the blank is plastically deformed in the mold cavity, it flows and slides along the surface of the cavity, causing severe friction between the surface of the cavity and the blank, which causes the mold to fail 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 the mold parts, the smaller the amount of wear and the better the wear resistance. In addition, abrasion resistance is also related to the type, quantity, form, size and distribution of carbides in the material.

2. Toughness

Most of the working conditions of the mold are very harsh, and some often bear large impact loads, which results in brittle fracture. In order to prevent the mold parts from being suddenly brittle during work, the mold must have high strength and toughness.

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

3. Fatigue fracture performance

During the work of the mold, under the long- term effect of cyclic stress, it often causes fatigue fracture. Its forms are small energy multiple impact fatigue fracture, tensile fatigue fracture contact fatigue fracture and bending fatigue fracture.

The fatigue fracture performance of a mold 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 mold is higher, the hardness and strength will be reduced, leading to early wear of the mold or plastic deformation and failure. Therefore, the mold material should have high resistance to tempering to ensure that the mold has higher hardness and strength at the working temperature.

5. Cold and hot fatigue resistance

Some molds are repeatedly heated and cooled during the working process, which causes the surface of the cavity to be stretched and pressure to change the stress, which causes surface cracking and peeling, increases friction, hinders plastic deformation, and reduces dimensional accuracy, which leads to Mold failure. Hot and cold fatigue is one of the main forms of failure of hot work molds, and this type of mold 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 will be separated into strong aggressive gases such as HCI and HF after heating, which will erode the surface of the mold cavity, increase its surface roughness, and increase wear and tear.

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Post time: Aug-19-2021