Abstract Tribological conditions in forming operations depend on several parameters such as tool-workpiece interface pressure, surface expansion, sliding length, sliding speed, tool and workpiece materials and the roughness of the parts. Among indirect parameters, the most influential one is the tool-workpiece interface temperature, which directly influences the lubricant performance. Prior to testing new tribo-systems to determine their limits of lubrication, it is therefore important to find the interface temperature. However, measurement of the interface temperature in metal forming is difficult. The present work investigates the determination of the interface temperature in an industrial ironing operation, where severe process parameters lead to lubricant film breakdown and galling after several strokes. The methodology combines finite element simulations and experimental measurements. The overall procedure is based on a steady-state thermal analysis to determine the temperature distribution within the tool and a transient thermo-mechanical analysis of the ironing process when steady-state conditions are achieved. Results show that the proposed methodology applied to a single stroke can effectively and accurately predict the interface temperature in the test tool, thus avoiding the otherwise required thermo-mechanical FEM analyses of hundreds of strokes to reach steady-state. Furthermore, the influence of parameters, such as the predicted steady-state tool temperature, the friction coefficient and the heat transfer coefficient on the contact temperature, is analysed. It is concluded that the frictional heating is the primary cause for the peak temperature. By calibration of the friction coefficient and the heat transfer coefficient to ensure matching of the numerical results and the experimental measurements, a maximum tool-workpiece interface temperature of 158 °C was determined during the forward stroke and 150 °C during the backward stroke.

中文翻译：

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确定工业熨烫操​​作中接触温度的组合数值和实验方法

摘要 成形操作中的摩擦学条件取决于工具-工件界面压力、表面膨胀、滑动长度、滑动速度、工具和工件材料以及零件的​​粗糙度等几个参数。在间接参数中，影响最大的是工具-工件界面温度，它直接影响润滑剂的性能。在测试新摩擦系统以确定其润滑极限之前，找到界面温度很重要。然而，金属成形中界面温度的测量是困难的。目前的工作调查了工业熨烫操​​作中界面温度的确定，其中严重的工艺参数会导致润滑油膜在几次冲程后破裂和磨损。该方法结合了有限元模拟和实验测量。整个过程基于稳态热分析，以确定工具内的温度分布，并在达到稳态条件时对熨烫过程进行瞬态热机械分析。结果表明，所提出的应用于单个行程的方法可以有效且准确地预测测试工具中的界面温度，从而避免了否则需要对数百个行程进行热机械 FEM 分析才能达到稳态。此外，还分析了预测的稳态工具温度、摩擦系数和传热系数等参数对接触温度的影响。结论是摩擦加热是峰值温度的主要原因。通过摩擦系数和传热系数的校准以确保数值结果与实验测量的匹配，在向前冲程期间确定了 158 °C 的最大工具 - 工件界面温度，在向后冲程期间确定了 150 °C。