Tribological Phenomenon under Extreme Conditions and Its Application

在本研究中，极端条件意味着材料的接触压力大于屈服应力。在金属成形过程中也认识到同样的条件。采用熨烫式摩擦试验机对镀锌钢与模具钢D2的摩擦特性进行了试验。得到以下结果。(1) GA钢和GAE钢的镀锌层在熨烫过程中被破坏。镀锌层的裂纹使工件无法保持适度的润滑膜，因此在这些材料中，镀锌层本身的原始摩擦特性占主导地位。润滑油对熨烫还原和粘度的影响很小。(2) EG的镀锌层易跟随块状变形，在熨烫过程中不会破坏，因此润滑剂对润滑状况的影响很大。EG镀锌层的摩擦特性不如GA、GAE和EL，但可以通过使用润滑剂来降低摩擦应力。(3)硫对含锌材料具有极端添加剂的能力，而磷酸盐添加剂对含铁材料具有优异的减摩能力。

In this research the extreme condition means higher contact pressure than yield stress of materials. The same conditions are recognized in metal forming processes. By using the ironing-type friction testing machine frictional characreristics of galvanized steel against die steel D2. The following results are gained.(1)Galvanized layr are destroyed during ironing process in GA and GAE steel. Clacks of galvanized layr makes it impossible to maintain a moderate lubrication film on workpiece, therefore in these materials the original frictional characteristics of layr itself are dominant. The effects of ironing reduction and viscosity of lubricants are very small.(2)The galvanized layr of EG are easy to follow the deformation of bulk and will not destroy during ironing, therefore the lubricant has big effect on lubrication condition. The frictional characteristics of galvanized layr of EG are not so good as GA, GAE and EL, but it is possible to reduce frictional stress by using lubricants.(3)Sulfur has an ability of extreme additives to the materials which has Zn as component, on the other hand phosphate additives has an excellent ability to reduce friction for the materials which has Fe component.