The Use of Workability Test Results to Predict Processing Limits

  • A. L. Hoffmanner

Abstract

The concept of workability testing was developed from accurate determinations of the states of stress under which a material is deformed during testing. These results provided a general relationship between stress and fracture strain from a variety of tests and materials over a wide range of stress, strain rate and temperature. It was found that the major stress parameter determining the fracture strain ε¯f was the average value of the normal stress σT perpendicular to the direction of alignment of grain boundaries and second phase particles. This definition of stress provided the ductile fracture criterion lnεi¯f = A + B σT/ σ¯ in which σ¯ is the flow stress and A and B are material parameters related to the mechanical behavior of the solid solution and mechanical texturing respectively. The workability concept subsequently was amplified by applying the test results to make accurate predictions of working limits during forging, extrusion and rolling. Good agreement was found between predictions and observations when the mechanics of the processes were defined by analytical and experimental-analytical procedures. These results will be extended to support qualitative procedures for process improvements by isolating the factors which are most prominent in determining the limiting reductions during deformation processing.

Keywords

Titanium Anisotropy Zirconium Convection Torque 

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Copyright information

© Springer Science+Business Media New York 1971

Authors and Affiliations

  • A. L. Hoffmanner
    • 1
  1. 1.TRW Inc.ClevelandUSA

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