塑性加工における焼付き発正機構の研究 : 第2報,押出し形摩擦試験における潤滑油膜厚さの評価

抄録

An oil film thickness at the tool-work interface was estimated theoretically in an extrusion-type friction test, to examine the effects of oil film thickness on seizure initiation. It has been presumed that a lubricant oil is trapped between the tool and the workmetal when the workmetal is filling up a die chamber. The trapped oil film thickness calculated could be varied in a range less than about 2 μm by changing the viscosity grade and the applied thickness of the mineral oil. Furthermore, it has been presumed that the trapped oil film thickness reduces with the punch stroke owing to the surface expansion of the workmetal and the contact pressure distribution. The oil film thickness calculated decreased toward the die exit, where it was less than 0.4μm. The ratio of the oil film thickness at the die inlet to that at the die exit could be varied in a range from 3.7 to 5.5.