Research on the flow stress characteristics of AISI 1006 and AISI 5140 in the temperature range of warm forging by means of thermo-mechanical experiments

The flow stress is one of the most essential parameters that reflect the capability of a material in plastic deformation. It is also an important factor that affects the precision of finite element (FE) simulation. However, recent research on material flow stress has focused mainly on cold and hot forging: as to warm forging, little research has been done on this aspect. With the gradually widening use of warm forging technology in precision plastic forming, the determining of the material flow stress systematically and accurately becomes the basis of further research on material plastic deformation. In this paper, the changing rule of the flow stress of AISI 1006 and AISI 5140 in the temperature range of warm forging has been analyzed systematically through thermo-mechanical experiments. The research considers sufficiently the influence of forming temperature, effective strain and strain rate. The experimental results offer a solid theoretical basis for the foundation of a mathematical model of flow stress, FEM simulation, for the calculation of the forming load, and for the working-out of the forming process.