Effects of lubricants on the rolling performances of cold rolled copper strips

摘要

Two parameters in rolling process, the forward slip value (S_h) and the minimum rolling gauge (h_(min)) were tested using a 4-high rolling mill in order to investigate the rolling performances of cold rolled copper strips under different lubricating conditions viz, lubrication with (i) base oil, (ii) base oil with 0.5wt.% oiliness, (iii) base oil with 0.5wt.% dialkyldithiophosphateester(DDE) and (iv) base oil with 0.25wt.% DDE and 0.25wt.% molybdenum dialkyldithiophosphate (MoDDP). The surface roughness of rolled copper strips was measured by a laser scanning confocal microscope. The surface morphologies of copper strips were observed by a scanning electron microscopy (SEM) and the compositions of the surface residues were analyzed with an energy dispersive spectrometer (EDS). Results showed friction coefficients, which were calculated by S_h with different lubricants ranged from 0.067-0.302. The surface topography of copper strips showed smooth and the plowing wear was finer. Meanwhile, when the lubricant was base oil with 0.25wt.% DDE and 0.25wt.% MoDDP, the h_(min) of copper reached 19μm, a value satisfied the copper foil conduction. However, with the addition of EP additives, the topographies showed some grind pits at local region. Indicating that EP additives containing P, S, Mo moieties possess a better thickness-reducing performance, but cause corrosion at the same time.