| 模具选材 |
| 添加时间：2018/10/12 16:36:53 浏览次数： |
| 条件要求 Conditional requirements 1、耐磨性 1. Wear resistance 坯料在模具型腔中塑性变性时，沿型腔表面既流动又滑动，使型腔表面与坯料间产生剧烈的摩擦，从而导致模具因磨损而失效。所以材料的耐磨性是模具最基本、最重要的性能之一。 When the blank is plastic deformed in the cavity, it flows and slides along the surface of the cavity, resulting in severe friction between the cavity surface and the blank, which leads to the failure of the die due to wear. Therefore, the wear resistance of materials is one of the most basic and important properties of dies. 硬度是影响耐磨性的主要因素。一般情况下，模具零件的硬度越高，磨损量越小，耐磨性也越好。另外，耐磨性还与材料中碳化物的种类、数量、形态、大小及分布有关。 Hardness is the main factor affecting wear resistance. Under normal circumstances, the higher the hardness of the die parts, the smaller the wear volume and the better wear resistance. In addition, the wear resistance is also related to the type, quantity, shape, size and distribution of carbide in the material. 2．强韧性 2. toughness 模具的工作条件大多十分恶劣，有些常承受较大的冲击负荷，从而导致脆性断裂。为防止模具零件在工作时突然脆断，模具要具有较高的强度和韧性。 Most of the working conditions of the dies are very bad, and some of them often bear a 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. 模具的韧性主要取决于材料的含碳量、晶粒度及组织状态。 The toughness of the mold depends mainly on the carbon content, grain size and microstructure of the material. 3．疲劳断裂性能 3. fatigue fracture properties 模具工作过程中，在循环应力的长期作用下，往往导致疲劳断裂。其形式有小能量多次冲击疲劳断裂、拉伸疲劳断裂接触疲劳断裂及弯曲疲劳断裂。 During the working process of the die, fatigue fracture is often caused by the long-term effect of cyclic stress. Its forms are low energy multiple impact fatigue fracture, tensile fatigue fracture contact fatigue fracture and bending fatigue fracture. 模具的疲劳断裂性能主要取决于其强度、韧性、硬度、以及材料中夹杂物的含量。 The fatigue fracture properties of the die mainly depend on its strength, toughness, hardness and the content of inclusions in the material. 4．高温性能 4. high temperature performance 当模具的工作温度较高进，会使硬度和强度下降，导致模具早期磨损或产生塑性变形而失效。因此，模具材料应具有较高的抗回火稳定性，以保证模具在工作温度下，具有较高的硬度和强度。 When the working temperature of the die is higher, the hardness and strength of the die will decrease, resulting in early wear or plastic deformation of the die and failure. Therefore, the mold material should have high tempering stability to ensure that the mold at the working temperature, with high hardness and strength. 5．耐冷热疲劳性能 5. cold and thermal fatigue resistance 有些模具在工作过程中处于反复加热和冷却的状态，使型腔表面受拉、压力变应力的作用，引起表面龟裂和剥落，增大摩擦力，阻碍塑性变形，降低了尺寸精度，从而导致模具失效。冷热疲劳是热作模具失效的主要形式之一，帮这类模具应具有较高的耐冷热疲劳性能。 Some dies are in the state of repeatedly heating and cooling in the working process, which causes the surface of the cavity to be cracked and spalling under the action of tension and pressure changing stress, increases the friction force, hinders the plastic deformation, reduces the dimensional accuracy, and leads to die failure. Cold and hot fatigue is one of the main failure modes of hot working dies, which should have high cold and hot fatigue resistance. 6．耐蚀性 6. corrosion resistance 有些模具如塑料模在工作时，由于塑料中存在氯、氟等元素，受热后分解析出HCI、HF等强侵蚀性气体，侵蚀模具型腔表面，加大其表面粗糙度，加剧磨损失效。 Some molds, such as plastic molds, when working, because of chlorine, fluorine and other elements in the plastics, decompose and precipitate HCI, HF and other strong corrosive gases after heating, which corrode the surface of the mold cavity, increase its surface roughness, and aggravate wear failure. |
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