Tribological Properties of Lubricants used in PM Process
This study is a step towards of developing a means for predicting the performance of solid powder lubricant used in P/M process. Lubricant is an indispensable part of the P/M process. Lubricants are often used admixed with metal powders in order to reduce adhesion and friction between powder particles and between powder and the die-wall during the filling, compaction and the ejection process. The lubricants are often solid organic substances such as metallic stearates and amide wax. During compaction and ejection of a component the lubricant is exposed to high pressure and high shear stress. Experiments have been performed to evaluate tribological properties of lubricants from different aspects under such conditions. A powder friction-measuring device (PFMD) has been used to evaluate the friction of the powder die-wall contact. Results obtained from friction measurements using PFMD are shown to correlate well with the results from real pressing process. This paper will describe the performance of lubricants including Amide wax, Kenolube and Zinc stearate regarding friction properties.