FIELD: technological processes.
SUBSTANCE: invention relates to the field of electroplating and can be used for the metallization of a threaded connection of pipelines or pipes. Solution that does not contain cyanide contains copper pyrophosphate, tin pyrophosphate, zinc pyrophosphate, pyrophosphate as the complexing agent for the metal and at least one sulfur-containing compound in an amount of 40 g/l or less (excluding 0), which is selected from the group consisting of the mercapto compound defined by chemical formula (1), the sulfide compound defined by chemical formula (1), the dimer formed by the disulfide bond of the mercapto compounds, and their salts: RS-(CHX1)m-(CHX2)n-CHX3X4 (1), where m and n are integers 1 or 0, each of X1, X2, X3 and X4 is any one of hydrogen, OH, NH2, SO3H or CO2H, except for the case when X1, X2, X3 and X4 all are hydrogen, and R is any one of hydrogen, methyl group or ethyl group. Method includes the step of preparing the metallization solution and the step of exposing the pin or lock of the threaded joint to the electrolytic coating using a metallization solution to form a metallization film from the Cu-Sn-Zn alloy on a nipple or lock.
EFFECT: metallization films have excellent resistance to frictional corrosion, to crevice corrosion, and to corrosion from external influences.
2 cl, 1 tbl
