Metalworking fluid containing a branched alcohol propoxylate

A method of processing a workpiece comprising

• a) contacting a tool and a workpiece to effect a change in the shape of the workpiece, and
• b) applying a metalworking fluid to a surface area where the tool and the workpiece are in contact,
• where the metalworking fluid contains a propoxylate of the formula R—O—(CH2—CH(CH3)—O)n—H, where R is a branched C10 to C13 alkyl and n is from 5 to 25, and wherein the metalworking fluid is formulated as
• a straight oil, which contains the at least 80 wt % of a propoxylate, and which is applied without dilution of water;
• a soluble oil, which contains 30 to 85 wt % mineral oil and up to 20 wt % propoxylate, and which is applied after dilution with water as aqueous emulsion;
• or
• a semi-synthetic fluid, which contains 5-30 wt % mineral oil, 30-50 wt % water, and up to 20 wt % propoxylate, and which is applied without dilution of water.