Approximate Methods for the Calculation of Loads and General Flow Patterns When Forging Real Materials

Summary

This paper describes means for utilising Upper Bound type of analyses for processes involving materials which are not perfectly plastic. Experimental results from two types of forging operation are described and compared with experimental predictions obtained by adopting different approaches to the application of analyses to real situations.

Using a strain dependent expression for flow stress provides a means for over estimating loads, whereas using the concept of an experimentally derived equivalent flow stress, enables accurate estimates of load to be made, for interpolated shapes.

Predicting the geometry of forgings is shown to be possible, but the choice of velocity field is shown to have a significant effect on accuracy.