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在挤压黑色金属材料时,冷挤压凹模要承受相当高的工作内压,其值可达250kgf/mm~2。在这样高的内压作用下,很易引起凹模的早期损坏,损坏形式主要是纵向或横向开裂。这直接影响到冷挤压工艺的经济效果和推广使用。为了正确地采用行之有效的措施来防止凹模的早期损坏,首先必须对凹模在工作时的应力应变作出符合实际情况的分析。另外,目前广泛采用预应力组合凹模来提高凹模的强度,预应力的大小对凹模强度有明显的影响,因此,采用最佳预紧力是进一步提高凹模强度的途径之一。
In the extrusion of black metal, cold extrusion die to withstand a very high working pressure, the value of up to 250kgf / mm ~ 2. In such a high internal pressure, it is easy to cause early damage to the die, the main form of damage is vertical or horizontal cracking. This directly affects the economic effect of cold extrusion process and promote the use of. In order to properly use effective measures to prevent the early damage to the die, die must first be in the work of stress and strain to make a realistic analysis. In addition, the prestressed composite die is widely used to increase the strength of the die. The prestressing force has a significant effect on the die strength. Therefore, adopting the best pretension force is one of the ways to further improve the die strength.