PLATING SOLUTION FOR THREADED CONNECTION FOR PIPE OR TUBE AND PRODUCING METHOD OF THREADED CONNECTION FOR PIPE OR TUBE
Provided is a plating solution for a threaded connection for pipe or tube used for forming a plating film excellent in galling resistance, crevice corrosion resistance, and exposure corrosion resistance. The plating solution for a threaded connection for pipe or tube of the present embodiment contains no cyanide, but contains: a water-soluble copper salt; a water-soluble tin salt; a water-soluble bismuth salt; a free acid; and a thiourea-based compound of 10 g/L or less (excluding 0) that is represented by Chemical Formula ( 1 ): X 1 X 2 N—C(═S)—NX 3 X 4 (1), where each of X 1 , X 2 , X 3 , and X 4 is any one of hydrogen, an alkyl group, an allyl group, a tolyl group, or a group represented by Chemical Formula (2), but excluding that X 1 , X 2 , X 3 , and X 4 are all hydrogen: —CH 2 —CH 2 —S—CH 2 —CH 2 —X 5 (2), where X 5 is OH or NH 2 .
1 . A plating solution for a threaded connection for pipe or tube, the plating solution containing no cyanide,
the plating solution comprising:
a water-soluble copper salt; a water-soluble tin salt; a water-soluble bismuth salt; a free acid; and a thiourea-based compound of 10 g/L or less (excluding 0) that is represented by Chemical Formula (1):
X 1 X 2 N—C(═S)—NX 3 X 4 (1),
where each of X 1 , X 2 , X 3 , and X 4 is any one of hydrogen, an alkyl group, an allyl group, a tolyl group, or a group represented by Chemical Formula (2), but excluding that X 1 , X 2 , X 3 , and X 4 are all hydrogen:
—CH 2 —CH 2 —S—CH 2 —CH 2 —X 5 (2),
where X 5 is OH or NH 2 .
2 . A producing method of a threaded connection for pipe or tube comprising:
a step of preparing the plating solution according to claim 1 ; and
a step of subjecting a pin or a box of the threaded connection to electroplating using the plating solution so as to form a Cu—Sn—Bi alloy plating film on the pin or the box.