The Role of Lubrication in the Cold Heading of Mild Steel

This work provides information leading to the evaluation of the coefficient of friction for various lubricants during the first blow of a double blow heading operation on AISI 1018 steel wire. A Waterbury-Farrel cold heading machine was instrumented so that the total force and frictional force could be evaluated during the first blow operation. The lubricants investigated fell into four main groups: 1) Lubricants, physically or chemically bonded to the wire; this group included zinc phosphate, 2) Lubricants listed in 1) used together with a petroleum based polar oil, SAE 30 [780 SUS at 80° F (167 × 10⁻⁶ m²/s at 27° C)], 3) Liquid lubricants of various viscosities employed with the bare wire, 4) Solid lubricants mixed with a non-polar mineral oil [65 SUS at 80° F (12 × 10⁻⁶ m²/s at 27° C)], again used with bare wire. The calculated coefficient of friction was used to indicate the efficiency of the respective lubricants. Liquid lubricants either alone on bare wire or with bonded lubricants proved to be the most successful in reducing the calculated μ value; additives appeared to play a minor role. The results indicate that a low cost liquid lubricant used on bare wire has both economic and operational advantages when cold heading mild steel wire.