CIRP Encyclopedia of Production Engineering

2014 Edition
| Editors: The International Academy for Production Engineering, Luc Laperrière, Gunther Reinhart

Flow Stress, Flow Curve

  • Alan Bramley
Reference work entry


Relationship between true stress and strain for a given material undergoing plastic deformation.

Related Terms

Stress–strain curves; work/strain hardening curve

Theory and Application


In metal-forming technology a major parameter is the load or force required to perform the operation. This is dependent on the geometrical configuration, friction at the tool–workpiece interface, and the mechanical resistance to plastic flow of the workpiece material and in turn determines the required force and energy capacity of the machine tool being used. This mechanical resistance of the workpiece material is defined by its flow curve which can be established independently by testing. Thus, in modelling of a forming process, the flow curve of the workpiece material is an essential prerequisite and for this purpose the use of empirical stress–strain curves and constitutive relations are used.

The flow curve is best explained by considering a simple uniaxial tensile test...
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Copyright information

© CIRP 2014

Authors and Affiliations

  • Alan Bramley
    • 1
  1. 1.Mechanical EngineeringUniversity of BathBathUK