Stress analysis of a cold forging process applied to a countersunk headed fastener
Stress analysis of a cold forging process applied to a countersunk headed fastener
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DOI：
10.1016/0924-0136(93)90018-2
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发表时间：
1993-10
影响因子：
6.3
通讯作者：
J. Monaghan
中科院分区：
文献类型：
--
作者：
J. Monaghan
在高强度封头紧固件的制造中，经常采用冷锻工艺。这些工艺的特点通常是工具负荷和应力较高，因此存在工具失效的风险。工程师们越来越多地试图更好地了解闭式冷锻作业中产生的金属流动的性质。这样做是为了建立更可靠的工艺数学模型，帮助选择最合适的成型机，并设计用于这些成型机的模具。本文对沉头紧固件冷锻过程中产生的金属变形进行了实验和理论分析。作者用平板分析方法推导了凸模-工件界面和平均锻造压力的一组表达式。用导出板分析方程得到的界面压力和平均锻造压力的预测值与使用标准开式挤压和圆柱体压缩公式得到的结果进行了比较。将每种理论变形模型的预测结果与一系列锻造试验的结果进行了比较。结果表明，板解析表达式预测的结果与实验结果吻合较好。此外，还确定了所导出的方程的形式可以很容易地满足界面摩擦条件和模模角的变化。
Cold forging processes are used frequently in the manufacture of high-strength headed fasteners. These processes are characterised often by high tool loads and stresses with the consequent risk of tool failure. Increasingly, engineers are attempting to develop a better understanding of the nature of the metal flow arising during closed-die cold-forging operations. This is being done in an effort to establish more reliable mathematical models of the process, to aid in the selection of the most appropriate forming machines, and in the design of the tooling to be used on these machines. The work reported in this paper involves an experimental and theoretical analysis of the metal deformation arising during the cold forging of countersunk headed fasteners. A set of expressions for the punch—workpiece interface and the mean forging pressure were derived by the author using the slab-analysis method. The predicted values for interface and mean forging pressures obtained using the derived slab-analysis equations were compared with results obtained using standard open-extrusion and cylinder-compression expressions. The results predicted using each of the theoretical deformation models were compared with those obtained from a series of experimental forging tests. It was found that the slab-analysis expressions predicted results that were in close agreement with those obtained experimentally. Furthermore, it was determined that the form of the derived equations was such that changes in both interfacial friction conditions and die angles could be catered for very easily.