subject: Mold material selection of the three principles of - Slurry Pump EGM manufacturer [print this page] Mold material selection of the three principles of - Slurry Pump EGM manufacturer
(A) die to meet the conditions of work requirements
1, wear resistance
Blank in the mold cavity, when the plastic degeneration along the cavity surface of both the flow will be sliding, so that the cavity surface and a sharp friction between billet, resulting in mold failure due to wear and tear. Therefore, the wear-resistance is the basic mold, one of the most important performance.
Hardness of the main factors affecting the abrasion resistance. In general, the higher the hardness of mold parts, wear smaller, the better wear resistance. In addition, the wear resistance of carbide with the material type, quantity, shape, size and distribution of the.
2, strength and toughness
Most of the mold very poor working conditions, and some often bear a greater impact load, resulting in brittle fracture. To prevent the mold parts in the work of a sudden brittle fracture, die to have a high strength and toughness.
Die toughness depends on the carbon content of the material, grain size and organization of the state.
3, fatigue fracture properties
Die working process, in the long-term under the action of cyclic stress, often resulting in fatigue fracture. In the form of a small number of energy impact fatigue fracture, fatigue fracture of tensile and bending the contact fatigue fracture fatigue fracture. Die fatigue fracture performance depends largely on its strength, toughness, hardness, and material content of inclusions.
4, high temperature performance
When the mold into a higher operating temperature, hardness and strength will decrease, leading to early die wear or plastic deformation and failure. Therefore, the mold material should have high resistance to tempering stability, to ensure that mold working temperature, high hardness and strength.
5, anti-fatigue properties of hot and cold
Some die in the course of their work at the repeated heating and cooling of the state, so that the cavity surface, tension, pressure, change the role of stress, causing cracking and peeling off the surface, increasing friction, prevent plastic deformation, reducing the size precision, resulting in die failure. Hot and cold fatigue is hot die, one of the main forms of failure to help these mold should have a high resistance to cold and heat fatigue.
6, corrosion resistance
Some molds, such as plastic mold at work, because there plastic chlorine, fluorine and other elements, the heat decomposition of precipitation after HCI, HF and other strong corrosive gases, erosion, mold cavity surface, increasing its surface roughness, increased wear failure.
(B) meet the technical performance requirements of mold
The manufacture of molds generally must go through forging, machining, heat treatment processes with a few. In order to ensure the mold manufacturing quality, reduce production costs, the material should have good malleable nature of cutting machining, hardened nature of hardenability and can be grinding nature; should have a small oxidation, decarbonization sensitivity and quenching deformation tendency to crack.
1, malleable, and
Has a low deformation resistance of hot forging, plastic good, forging temperature range, forging crack cold cracking and a low propensity for precipitation of carbide network.
2, annealing process of
Spheroidization annealing temperature range, annealing hardness and the fluctuations in the low range of small, ball-based rate.
3, cutting of
Cutting large, low-loss tool, processing and low surface roughness.
4, oxidation, decarbonization sensitivity
When heated to high temperatures can be a good anti-oxidation pregnant, decarbonization slow and not sensitive to the heating medium, resulting in pitting tendency of small.
5, hardening of
After quenching with a uniform and high surface hardness.
6, hardenability
After quenching can get deeper hardened layer, using relaxation quenching medium can be hardened.
7, quenching distortion cracking tendency
Conventional quenching a small volume change, shape warping, distortion minor, a low propensity for abnormal deformation. The low sensitivity of conventional quenching cracking on quenching temperature and the workpiece shape is not sensitive.
8, may be grinding of
Wheel loss is relatively small, non-burn limit of large amount of grinding on the grinding wheel quality and cooling conditions are not sensitive, and less prone to injuries mill grinding cracks.
(C) die to meet the economic requirements
To die in the selection is the need to consider the economy of this principle, as much as possible to reduce manufacturing costs. Therefore, under the premise of satisfying the performance, first choose a lower price, and can be used do not need carbon alloy steel, can use domestic materials do not need to import materials.
In addition, selection should also consider the market of production and supply of the selected steels should be minimal and concentrated, easy to buy.
