A Novel Model Developed for Frictional Characteristics Analysis of Axial Symmetric Parts

Abstract

Friction during contact between metals can be very complex under dynamic conditions. In this study, friction between 304 stainless steel and SKD11 steel with boundary lubrication was studied experimentally using a friction testing machine (MPX-2000). The friction coefficients at different sliding speeds and interface loads were determined, and a new friction coefficient model was established based on the experimental data. The sample surfaces were analyzed using a laser-scanning microscope, and it was found that the friction mechanism under boundary lubrication (where 0.1 < μ < 0.3) was mainly abrasive wear accompanied by slight adhesive wear. The new friction coefficient model developed was applied for a simulation of Axial Symmetric U-Bend parts using finite element methods, and the results were compared with stamping experiments. The prediction errors in the results of thickness and the springback angle showed that the new friction model had a good agreement of the thickness distribution to the experiments with less than 10% error, and the springback angles between the new friction model and the measurements with the errors of 6.86% and 5.13%. The experimental results show that the friction coefficient decreases with the rise of speed when the sliding speed is between 30 mm/s–50 mm/s; the friction coefficient decreases with the increase in interface load. A decreasing trend of friction coefficient gradually slows down when the interface load is between 2.0 MPa–4.0 MPa. This also agrees with the simulations using the new model.