2006 Volume 47 Issue 7 Pages 1782-1787
High heat resistance is required for the lubricant used during the mass production of press formed magnesium parts using a warm press forming process. The heat resistance of a hindered ester has previously been found to be high, but insufficient at temperatures around 573 K. Therefore, further improvement of hindered ester-based heat resisting lubricants is required. This paper describes the influence on lubricity of adding aminic antioxidants to hindered esters. The results showed that excellent heat resistance was obtained by adding 5 to 20% styrenated diphenylamine. While a 5% addition improved heat resistance and inhibited lubricant degradation, addition of 10 or 20% additive resulted in decreased lubricity. Furthermore, the best lubricity was obtained when DLC-coated carbide was used as the die material in combination with the lubricant containing aminic antioxidant.
