冷間鍛造用潤滑被膜の摩擦特性に及ぼす
被膜下地表面処理の影響

抄録

A series of experiments have been carried out using an upsetting-extrusion-type tribometer to investigate the effect of the surface preprocessing of a workpiece on the friction behavior of dry in-place type lubricant coating. Experiments were carried out in the transition range of seizure for tool surface reduced peak height. Experiments using a typical conversion lubricant coating and dry in-place type lubricant coated on seven types of preprocessed surface showed that the tribo-performance of the dry in-place type lubricant coated on an acid-pickled and shot-blasted surface is insufficient. However, the dry in-place type lubricant coated on a shot-blasted surface in two stages using microscopic particles or phosphates as thin films gives excellent antiseizure performance and keeps the frictional shear factor low up to a tool surface reduced peak height Rpk of 0.07μm, the critical Rpk for the conversion lubricant coating is 0.05μm. The observation of a forged surface showed that the excellent performance of dry in-place type lubricant coated on a shot-blasted surface in two stages is due to its combined surface texture.