US 6,231,687 B1Granted

Lubrication treatment method for cold working of steel

AssigneeHenkel Corporation

InventorsNaoyuki Kobayashi, Masahiko Kawakami

Life of this patent

Estimating the term…

Loading patent…

Abstract

A phosphating solution that contains from 3 to 30 g/l of zinc ions, from 0.1 to 20 g/l of ferrous ions, from 5 to 60 g/l of phosphate ions, from 5 to 60 g/l of nitrate ions, and a source of hydroxylamine in a concentration corresponding stoichiometrically to from 0.5 to 4 g/l of hydroxylamine and in which there is a weight ratio of zinc to phosphate that is from 0.1:1 to 1:1 deposits on steel to be cold worked a phosphate conversion coating suitable as a lubricant carrier. This phosphating solution, which may optionally contain one or more of calcium, nickel, cobalt, and copper cations and simple and complex fluorine-containing anions, makes it possible to lower the temperature of the treatment solution, reduce the amount of sludge, improve the quality of the coating film, and allow single-liquid type replenishment to be used. Preferably the surface to be phosphated is immersed in the phosphating solution, maintained at a temperature of 35 to 80° C., for 2 to 20 minutes.

Claims20

Dependent claims

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.

11 more elements

Dependencies are inferred from the claim text.