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一、前言金属在挤压的过程中,挤压筒壁及凹模要承受相当高的工作压力和接触摩擦。在热挤压时,还必须承受温度变化。因此,挤压模具的磨损、热疲劳、甚至开裂时有发生。在挤压筒的设计中,往往采用厚壁筒的假设,认为挤压过程中挤压筒所受的内压沿整个长度方向是均布的。但实验表明,挤压过程中筒壁上的接触应力的分布并不均匀,且与润滑条件、变形程度、凹模形状及变形金属的性质有关。因此,挤压中的接触问题为许多研究工作者所重视,作了许多有关的工作。这些工作所采用的主要方法有:(1)“压力销”法,
First, the preface Metal extrusion process, extrusion cylinder wall and concave die to withstand a very high working pressure and contact friction. In the hot extrusion, it must also withstand the temperature changes. Therefore, the extrusion die wear and tear, thermal fatigue, cracking occurs even from time to time. In the design of extrusion barrel, the assumption of thick-walled barrel is often adopted. It is considered that the internal pressure received by the extrusion barrel during extrusion is uniform along the entire length. However, experiments show that the distribution of contact stress on the tube wall during extrusion is not uniform and is related to the lubrication conditions, the degree of deformation, the shape of the die and the nature of the deformed metal. Therefore, the problem of contact in extrusion is paid more attention by many researchers and many related work has been done. The main methods used in these tasks are: (1) “pressure pin” method,