Determining the influence of surface roughness on materials flow of various materials using grid lines during cold forming

Purpose - The purpose of this paper is to determine the influence of surface roughness on materials flow of various materials using grid lines during cold forming. Design/methodology/approach - The study is focused on the investigation of the influence of the surface roughness on the materials flow for different materials using grid lines in the upsetting. Stainless steel, SAE 1020 steel, commercially pure aluminum, commercially pure copper and CuZn(40)Pb(2) brass are used as the test materials. Upsetting process is applied to the cylindrical specimens using the flat end dies. Strain distributions on the free surfaces of cylindrical upset specimen are measured for different upsetting reductions. Strain distributions on the free surfaces are obtained by the measurements of the dimensions of the square grid elements before and after the upsetting process. Experimental results are placed into graphical plots. Findings - It is found that surface roughness is effectual on the strain changes on the free surfaces with the increasing deformation ratio for especially two types of steel specimens. There has been no considerable effect on aluminum, copper and brass specimens. Research limitations/implications - It would be interesting to search the surface roughness, R(sk) and other parameters describing the bearing properties of the surface of more materials. Future work could be concentrated on the cold forming of these materials. Practical implications - Different forming technologies are nowadays widely applied in mass production of mechanical components for needs of transportation, electronics, household appliances, etc. In order to reduce costs, manufacturers are trying to minimize additional machining and therefore to implement the influence of surface roughnesses on materials flow of various materials. Originality/value - The main value of this paper is to contribute to studies on the influence of surface roughness on materials flow of various materials.