Abstract
Many investigations have been made on the earing phenomenon of deep-drawn cup. In predicting the relationship between texture and earing, caluculations have been carried out on the assumption that only the circumferential compressional stress is effective for the development of ears. Assuming as a first approximation that the radial and circumferential stresses equal in magnitude are uniformly distributed in the blank. Tucker has obtained good agreement between the predicted and experimentally measured values for cups pressed from aluminum single crystals.
To clarify the reason of such a good agreement in spite of the unrealistic assumption of such an overall uniform stress field, strain measurments during deep-drawing have been made on the blank of the cubically oriented copper sheet. From the measurment of strain variations in the blank during the deep-drawing operation, validity of Tucker’s assumption can be explained. In this deep-drawing process, fractures are observed to initiate in the parallel and perpendiclar directions to the rolling direction where the r-values are maximum and the elongation to fracture is minimum.
