عنوان مقاله [English]
Determination of required force during forging processes. So, in order to increase the accuracy of numerical simulation results at die design process and predicting the required force, it is necessary to do suitable tests to estimate the friction coefficient of the process. In this research, a new test method named open die compression of the cylindrical rod has been presented and the calibration curves have been developed for it. Then, this test and the well-known ring compression test have been used to predict the friction coefficient in isothermal forging process of a sample gas turbine compressor Ti-6Al-4V blade. The friction coefficient determined by ring compression test has been applied for root region and the coefficient determined by open die compression of cylindrical rod test for the airfoil region of the blade. Finally, forging process has been investigated numerically and experimentally. Comparison of the maximum forces form numerical and experimental results shows acceptable agreement. The results show that open die compression of cylindrical rod test is a reliable method for evaluating the friction. The difference between friction coefficients determined by two before mentioned test methods, shows the dependence of friction coefficient value on deformation state of the workpiece.