We are currently producing a lead wire rod but when drawing, the wire in the wire drawing machine turns a blackish colour. Can any one suggest to me what the resolution is and what type of chemical we should be using in the drawing machine?
The black color you see on the surface of the lead placed in the drawing machine must be lead sulfide. (PbS) which is also known as galena. en.wikipedia.org/wiki/Lead%28II%29_sulfide This must have something to do with a sulfur compound such as mild sulfuric acid contaminating your drawing solution.
I don't think you will find many experts in drawing lead in this Forums. I was under the impression that lead was hot extruded with a lead press and thus never drawn at all because of its very low tensile strength.