DETERMINATION OF COEFFICIENT OF FRICTION DURING COLD RING UPSETTING PROCESS WITH DIFFERENT LUBRICANTS

Abstract

Contact friction during plastic deformation is always variable and it is highly dependent on the used lubricants. This paper presents the results of determining the coefficient of friction when cold plastic deformation by the method of cold ring upsetting with different lubricants. The ring upsetting process is performed with varying degrees of deformation with three lubricants used: industrial oil, cooking oil, and zinc sulfate powder. Based on the deformation and dimension change of the samples after the upsetting, the coefficient of friction was determined by correlation comparison with the friction calibration curve performed by Male and Cockcroft. A process of verifying the experimental results is carried out on Deform 2D numerical simulation software. Simulation of the ring upsetting process with the same experimental conditions and with the coefficients of friction determined. The dimension of the samples after the deformation simulation is compared with the sample dimension after the weasel to confirm that the results of determining the coefficient of friction are reliable.