FIELD: chemistry; metallurgy.
SUBSTANCE: invention relates to electroplating and can be used for the metallization of threaded joints of pipes or columns. Solution that does not contain cyanide contains water-soluble salts of copper, tin, bismuth, free acid, and a thiourea compound in an amount of 10 g/l or less (excluding 0) of formula (1): X1X2N-C(=S)-NX3X4 (1), where each of the groups X1, X2, X3 and X4 is any one of hydrogen, an alkyl group, an allyl group, a tolyl group or a group represented by the chemical formula (2), except when all groups X1, X2, X3 and X4 simultaneously represent hydrogen: -CH2-CH2-S-CH2-CH2-X5 (2), where X5 is OH or NH2. Process comprises preparation step of metallization solution given above, and an electrolytic coating step on the male member or female member of the threaded joint using a metallization solution so as to form a metallization film from the Cu-Sn-Bi alloy.
EFFECT: threaded joint with a coating has excellent resistance to friction wear, to crevice corrosion and to corrosion from external influences.
2 cl, 1 tbl
