Fracture Criterion for Materials in Plastic Deformation Processes.
Final rept. Apr 73-Apr 74,
CALIFORNIA UNIV BERKELEY DEPT OF MECHANICAL ENGINEERING
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The investigation is aimed at establishing the workability of aluminum alloy 7075-T6 in upsetting and rolling at room temperature with reference to occurrence of free-surface cracks. The fracture criterion was established by a plane-strain sheet tension test and an upset test. For obtaining the complete solution in upsetting an improved version of the matrix method was used. Then, a workability chart was constructed by combining the fracture criterion and the complete solution for various friction conditions and several special dimensions. In rolling, a mathematically sound theory was developed for the analysis of spread. With this theory it was possible to predict workability in rolling with reference to edge cracking. The limiting reductions in thickness were given as functions of workpiece dimensions for various friction values. Experimental results demonstrated that the predictions were very good.
- Metallurgy and Metallography