| abstract |
A lubricant composition suitable for use in hot forming processes of metals or alloys comprises (i) a major amount in total of at least one partially oxidised and/or partially polymerised unsaturated fatty acid glyceride; (ii) a minor amount in total of at least one pentaerythritol ester, and (iii) 1 to 10% in total of one or more additives, selected from metal dialkyl dithiophosphates and organic compounds, especially esters, of boric acid, capable of promoting the formation of carbon during use of the composition. Preferred components are (i) partially oxidised and/or polymerised linseed oil, (ii) pentaerythritol monooleate and (iii) a zinc dialkyl dithiophosphate. The compositions permit improved carbon layer lubrication at hot metal working temperatures with decreased formation of fumes and/or odours. |