In warm and hot forging processes, die life has a great effect on production cost and accuracy. Generally, the die life depends on plastic deformation, fatigue cracking, and wear. The die temperature during forming operation of warm and hot forging is relatively high due to the high temperature of f...
In warm and hot forging processes, die life has a great effect on production cost and accuracy. Generally, the die life depends on plastic deformation, fatigue cracking, and wear. The die temperature during forming operation of warm and hot forging is relatively high due to the high temperature of forging materials. The die life is, however, mainly affected by wear, among the several factors, because of low hardness of die at elevated temperature. Therefore, the prediction of die wear appears to forecast the die life. Here, the finite element analysis is adopted to predict die wear, which gives material deformation, die pressure, and temperature distributions of die an materials. In this study, constitutive equations were formulated in the function of strain, strain-rate, and temperature in view of the results from compression tests of SM45C. A series of finite element analysis have been conducted on hot forging of a hub, and warm forging of a rotor pole using the constitutive equations. For the prediction of die life, wear coefficients on the nitrided die surface have been experimentally measured, and the hardness distributions were expressed in terms of forming time and die temperature, while the conventional Archard's wear model does not include the effect of operation time. A new wear model has been proposed by considering the hardness softening of die expressed in terms of the main tempering parameter curve, and the variation of wear coefficient according to die depth. Then finite element analysis including the abovementioned effects has been conducted on the two forging operations of the hub and the rotor pole. The result of finite element analysis using the proposed wear model has been confirmed by comparing the analysis results with the experimental ones.
In warm and hot forging processes, die life has a great effect on production cost and accuracy. Generally, the die life depends on plastic deformation, fatigue cracking, and wear. The die temperature during forming operation of warm and hot forging is relatively high due to the high temperature of forging materials. The die life is, however, mainly affected by wear, among the several factors, because of low hardness of die at elevated temperature. Therefore, the prediction of die wear appears to forecast the die life. Here, the finite element analysis is adopted to predict die wear, which gives material deformation, die pressure, and temperature distributions of die an materials. In this study, constitutive equations were formulated in the function of strain, strain-rate, and temperature in view of the results from compression tests of SM45C. A series of finite element analysis have been conducted on hot forging of a hub, and warm forging of a rotor pole using the constitutive equations. For the prediction of die life, wear coefficients on the nitrided die surface have been experimentally measured, and the hardness distributions were expressed in terms of forming time and die temperature, while the conventional Archard's wear model does not include the effect of operation time. A new wear model has been proposed by considering the hardness softening of die expressed in terms of the main tempering parameter curve, and the variation of wear coefficient according to die depth. Then finite element analysis including the abovementioned effects has been conducted on the two forging operations of the hub and the rotor pole. The result of finite element analysis using the proposed wear model has been confirmed by comparing the analysis results with the experimental ones.
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