Patent ID: 6231687
Filing Date: 2001-05-15
Classification: B21J,C23C

Abstract:
A process for lubricating a steel workpiece surface prior to cold working that will cause deformation of the workpiece surface by mechanical force exerted between said surface and a distinct working tool surface, said process comprising operations of:(I) forming a phosphate conversion coating over said workpiece surface by contacting it with an aqueous phosphating composition comprising water and the following components:(A) dissolved zinc cations at a concentration of 3 to 30 g/l;(B) dissolved ferrous ions at a concentration of 0.1 to 20 g/l;(C) dissolved phosphate ions at a concentration of 5 to 60 g/l;(D) dissolved nitrate ions at a concentration of 5 to 60 g/l; and(E) a dissolved hydroxylamine source at a concentration of 0.5 to 4 g/l, calculated as its stoichiometric equivalent as pure hydroxylamine; and, optionally, one or more of the following components:(F) dissolved calcium ions at a concentration of 2 to 20 g/l;(G) dissolved metal cations selected from the group consisting of nickel, cobalt, copper; and(H) dissolved simple or complex fluoride anions, the weight ratio of zinc ions to phosphate ions in said phosphating composition being in a range from 0.1:1 to 1:1 and, if calcium is present in the composition at a concentration of at least 0.1 g/l, the weight ratio of calcium ions to zinc ions being in a range from 0.2 to 4; and(II) forming over the phosphate conversion coating formed in operation (I) a distinct lubricant coating.