Deformation of solid powder discs and strips under lubricated condition

Lubrication is of prime importance in many metal forming operations. This is especially true in case of cold working of materials where good lubrication is main key to the success of the process. Good lubrication improves the product quality and eliminates the harmful residual stresses in the product. Thus there is a substantial practical value in studying this mechanism of lubrication in forming processes. In this paper, the mechanism of lubricant trapping under dynamic compression is analyzed with hydrodynamics and flow stress of sintered preforms both under axisymmetric and plain-strain conditions. The pressure distribution and the thickness of the trapped lubricant film are calculated. Compression tests are carried out using a press in order to ascertain the analysis. The experimental results agree with the analytical results.