Which one of the following lubricants is most suitable for drawing mild steel wires?
Option (A)
Sodium stearate
Option (B)
Correct Option:
Question Solution:
Dry soap solution is used for slower drawing speed. Aqueous solution of soap is used for high drawing speeds and provides a bright surface.
The wire is coated with a thin coat of the ferrous hydroxide which when combined with lime acts as a filler for the lubricant. This process is called as the sulling. In the phosphating, a thin film of the manganese, iron or zinc phosphate is coated or applied on the wire which makes the lubricant to stick to the wire there by reducing the friction and consequently the drawing load. Another lubricant vehicle that is used in the wire drawing is a coating of the lime. After acid picking lime is applied and then allowed to dry. The lime neutralize any amount of the acid left on the surface and absorbs the lubricant for carrying it to solution. For the very thin wires, electrolytic coating of the copper is used to reduce the friction.