US 11,933,431 B2
Threaded connection for pipes
Kazuya Ishii, Tokyo (JP); Kunio Goto, Tokyo (JP); Masaaki Sugino, Tokyo (JP); and Yousuke Oku, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP); and VALLOUREC OIL AND GAS FRANCE, Aulnoye-Aymeries (FR)
Appl. No. 17/427,256
Filed by NIPPON STEEL CORPORATION, Tokyo (JP); and VALLOUREC OIL AND GAS FRANCE, Aulnoye-Aymeries (FR)
PCT Filed Feb. 7, 2020, PCT No. PCT/JP2020/004770
§ 371(c)(1), (2) Date Jul. 30, 2021,
PCT Pub. No. WO2022/016650, PCT Pub. Date Aug. 20, 2020.
Claims priority of application No. 2019-022973 (JP), filed on Feb. 12, 2019.
Prior Publication US 2022/0128178 A1, Apr. 28, 2022
Int. Cl. F16L 15/04 (2006.01); C25D 7/00 (2006.01)
CPC F16L 15/04 (2013.01) [C25D 7/003 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A threaded connection for pipes, comprising:
a pin including a pin side thread part, a pin side metal seal part, and a pin side shoulder part;
a box including a box side thread part, a box side metal seal part, and a box side shoulder part;
a shoulder part plating layer which is arranged on the pin side shoulder part and/or the box side shoulder part, and includes one or more layers, wherein an outermost layer of the shoulder part plating layer is a high friction coefficient plating layer; and
a non-shoulder part plating layer which is arranged on at least one of the pin side thread part, the pin side metal seal part, the box side thread part, and the box side metal seal part, and includes one or more layers, wherein an outermost layer of the non-shoulder part plating layer is a low friction coefficient plating layer having a coefficient of friction lower than a coefficient of friction of the high friction coefficient plating layer.