采用功平衡法求解管材挤压变形力的对比研究

Contrastive research of tube extrusion force deduced by the balanced work method

挤压是制备低塑性难变形金属和合金管材的一种精密成形方法,挤压力是选择挤压设备和校核挤压机部件强度的依据;合理地制定生产工艺规程和设计工模具等需要准确的计算挤压力,因此,求解计算精度高的挤压力计算公式在实际生产中显得尤为重要。本文在球坐标和柱坐标系下,采用功平衡法推导了锥模管材挤压变形力的两种理论计算公式;经生产中反复实验验证,两公式的计算结果都比较接近实测值,平均相对误差分别为6.6%左右、9.6%左右;而相关教材所给主应力法求解的管材挤压变形力公式计算结果的平均相对误差为15%左右。这表明本文推导的理论计算公式具有一定的工程实用性。

Extrusion is one type of the finishing processes in preparing the tube of the poor plastic metals and alloys that are difficultly deformed. Selecting extruders and checking strength of parts of them depend on the extrusion force. It is essential to calculate exactly the extrusion force for establishing reasonably regulations of production processes, designing implements and dies and so on. Therefore, it is very important to deduce the extrusion force＇s calcula- tion formula that is of very high accuracy in the production processes. In the spherical and cylindrical coordinate systems, two types of theoretical calculation formulas of tube extrusion force about cone dies have been determined by the balanced work method in this paper. Through the producing experiment, these formulas are validated repeatedly. It is shown that calculation results using the two formulas are close to the experimental results and that average relative errors are about 6. 6% and 9. 6% respectively. However, the average relative error of results given by calculation formula, determined by means of block method in the concerned reference books is about 15%. It is concluded that the theoretical calculation formulas in the paper could be used in certain engineering fields.