Experimental Study on Macro and Micro Characteristics of Powder Lubricant Layer in Frictional Warm Interface

Adding lubricant to warm forming interface can improve the quality of products, reduce the deformation force and extend the life of mold. Lubricant performance is different at elevated temperatures and affect the friction performance of the manufacturing interface. Using loose graphite powder to lubricate the plane contact tribopairs, a powder layer with good anti-friction ability was observed under the effect of axial load and shear. A multifunction tribometer is used to study temperature effect on friction characteristics of the powder lubrication in frictional warm interface. The scanning electron microscope observation, 3-d contour analysis, energy spectrum analysis, elements analysis and Raman analysis were used. The results show that temperature had great influences on friction characteristics of powder lubrication, the friction coefficient and smoothness. The integrity of powder layer and graphite ordering degree varied with temperature. These factors are the internal causes of effect of temperature on powder lubrication.