QUANTIFICATION OF GALLING IN SHEET-METAL FORMING BY SURFACE-TOPOGRAPHY CHARACTERIZATION

One of the major problems in forming of stainless steel sheet is galli ng due to lubricant film breakdown leading to scoring and bad surface quality In a Danish research programme new lubricants substituting the normally applied chlorinated paraffin oils are being developed and te sted for this purpose. In order to determine the limits of lubrication of these new lubricants, as well as commercial ones already available on the market, two sheet forming tests have been developed. Quantific ation of the degree of galling is done by roughness measurements on th e workpiece surface. In a ship reduction test, this is done by 2D prof ilometry at strip locations corresponding to different sliding lengths , whereas a deep drawing test is based on 3D roughness mapping of loca l areas. (C) 1998 Elsevier Science Ltd.