Much more important than people realize, your tyres are riding on this wire…
From my presentation to the Wire Association International in 2004. Still the most wonderful, talented group of engineers I know.
Lubrication in steel wire drawing operations generally brings soap powders to mind. For larger wires this is uniformly the case. The soap powder melts in the wire/die interface and provides a viscous film that supports the drawing force. The fillers and additives in the drawing soap impart polishing, extreme pressure, and many other properties to the lubricants. As wire sizes get smaller, the soap powders become unsuitable for high performance drawing. The viscosity of the molten film is too high, and the film occludes the hole, reducing the wire diameter and eventually breaking the wire. Additives may corrode the wires causing breaks. The polishing aids and other particulate materials may be drawn into the wire, weakening it and resulting in failures. Wet drawing lubricants are required to overcome this problem.
Wet drawing lubricants are based on water and/or oil and have considerably lower viscosities than the molten soaps they replace. This reduces the film thickness and the chances that the film will occlude or block the die orifice. Wet lubricants do not contain particulate materials, so foreign inclusions are not drawn into the surface from the lubricant. The additive level is much lower in a wet lubricant and can be controlled by dilution. The wet lubricants also provide cooling to the operation, a feature absent from dry drawing operations. The wet lubricant requires different maintenance techniques than those required for dry soaps. A comparison of the two types of wet lubricants and their individual requirements for usage will be presented.