Flow Characterization Focusing on Simultaneous Compensation of Temperature and Friction Using the Hot Compression Test

Abstract

Hot flow behaviors of an SCM440 alloy steel are characterized using a hot cylinder compression test, focusing on the simultaneous temperature-and-friction compensation (STFC) to numerically predict the stroke-compression load curves (SCLCs) with accuracy. A general and systematic STFC method is presented along with a detailed procedure, which can be easily computerized. The generalized C-m flow model (composed of the C-flow constant part, called the hot strength coefficient part, and the m-flow constant part, called the strain rate exponent part) is employed to characterize the ideal flow curves (IFCs) obtained directly from the cylinder compression test under isothermal and frictionless assumption. Only the hot strength coefficient part of the flow model is iteratively improved to reduce the strain rate-averaged errors of the SCLC at the sample strains between the calculated flow curves and IFCs. It has been found that the STFC method can steadily and remarkably reduce the errors after three iterations. Since the approach is systematic, it can be easily computerized.