Accession Number : AD0832589

Title :   ANALYTICAL PREDICTION OF DEFECTS FOR EXTRUSION THROUGH CONICAL DIES OF VARYING REDUCTIONS AND DIE ANGLES.

Descriptive Note : Technical rept. 1 Nov 65-30 Nov 67,

Corporate Author : CALIFORNIA UNIV BERKELEY

Personal Author(s) : Kobayashi, Shiro ; Altan, Taylan ; Lambert, Etienne R.

Report Date : JAN 1968

Pagination or Media Count : 141

Abstract : 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)

Descriptors :   (*EXTRUSION, DEFECTS(MATERIALS)), MATHEMATICAL PREDICTION, DIES, DEFORMATION, THEORY, MECHANICS, NUMERICAL ANALYSIS, TEMPERATURE, DISTRIBUTION, HEAT TRANSFER, FRACTURE(MECHANICS), NICKEL ALLOYS, STEEL, COPPER, REDUCTION OF AREA, CRACKS, STRESSES, DUCTILITY.

Subject Categories : Fabrication Metallurgy
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE