ANALYTICAL PREDICTION OF DEFECTS FOR EXTRUSION THROUGH CONICAL DIES OF VARYING REDUCTIONS AND DIE ANGLES.
Technical rept. 1 Nov 65-30 Nov 67,
CALIFORNIA UNIV BERKELEY
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The analytical prediction of defects encountered in extrusion requires a knowledge of the properties of the material and the mechanics of the deformation process. New developments in the upper-bound approach to steady-state deformation processes make it possible to obtain more realistic deformation characteristics because the assumed velocity fields no longer contain velocity discontinuities. By using this upper-bound method, the approximate stress, strain, and strain-rate distributions in the plastically deforming region can be obtained theoretically. It is necessary also to have information on the temperature distribution in order to determine the critical conditions for defects formation. For estimating the temperature distribution, a method was developed to solve numerically the three-dimensional heat transfer equation. Thus, detailed information on these quantities as functions of process variables becomes available. Comparison of theoretical results with the experiments shows good agreement. Author
- Fabrication Metallurgy