When it comes to the selection of the mold of the no-fire brick machine can not be ignored, the selection of material is an important link in the mold manufacturing process, simply said that the need to meet the strong toughness, wear resistance, corrosion resistance and other work needs, but also to meet the economic applicability. Henan Tongli Company to introduce to you the material selection of burnt-free brick machine mold six specific content:
1. Strength and toughness: most of the working conditions of molds are very harsh, and some of them often bear a large impact load, resulting in brittle fracture. In order to prevent the die parts from breaking suddenly when 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.
2. Wear resistance: when the blank is plastically deformed in the mold cavity, it flows and slides along the mold surface, causing severe friction between the mold surface and the blank, thus causing the mold failure due to wear. Therefore, the wear resistance of the material is one of the basic and important properties of the mold. Hardness is the main factor affecting wear resistance. Generally speaking, the hardness of mold parts is higher, the less wear, the better wear resistance. In addition, wear resistance is also related to the type, quantity, shape, size and distribution of carbides in the material.
3, corrosion resistance: when some molds, such as plastic molds, are working, due to the presence of chlorine, fluorine and other elements in the plastic, after being heated, they decompose out HCI, HF and other strong corrosive gases, which erode the cavity surface of the mold, increase its surface roughness, and make the wear more serious, resulting in failure.
4, high temperature performance: when the working temperature of the mold is high, it will reduce the hardness and strength, leading to the mold early wear or plastic deformation and failure. Therefore, the die material should have a higher tempering stability, to ensure that the die under the working temperature, with a higher hardness and strength.
5, cold and hot fatigue resistance: some molds in the working process in the state of repeated heating and cooling, so that the cavity surface by tensile, pressure stress, resulting in surface fracture and peeling, increase friction, prevent plastic deformation, reduce the size of precision, resulting in the failure of the mold. The cold and hot fatigue is one of the main forms of the failure of the hot die.
6. Fatigue fracture performance: During the working process of the die, fatigue fracture is often caused by the long-term action of cyclic stress. Its forms include low energy multi-impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture. The fatigue fracture performance of the die depends on its strength, toughness, hardness, and the content of inclusions in the material.