BOPI 03 BR / 2025 REPERTOIRE NUMERIQUE 16 (72) NAKAI, Yuya (JP) (73) 1-Nippon Steel Corporation, 6-1, Marunouchi 2-chome, Chiyoda-ku, TOKYO 1008071 (JP) et 2-Vallourec Oil And Gas France, 54, rue Anatole France, AULNOYE-AYMERIES 59620 (FR) (74) Cabinet Spoor & Fisher Inc. Ngwafor & Partners, The House of Gideon, Golf/Bastos Quater, Opposite The American Embassy, Entrance-Saint John Paul II Boulevard, P.O. Box 8211, YAOUNDE (CM). (57) This invention provides an oil well steel pipe with a threaded connection with which excellent galling resistance is obtained without using a compound grease, and which can suppress the occurrence of rust on a pin contact surface and can also keep shouldering torque at a low level. An oil well steel pipe with a threaded connection of the present disclosure includes a pipe main body 10 including a first end portion 10A and a second end portion 10B. The pipe main body 10 includes a pin 40 formed at the first end portion 10A, and a box 50 formed at the second end portion 10B. A light oil 80 is applied to a pin contact surface 400 of the pin 40. A solid lubricant coating 60 is formed on a box contact surface 500 of the box 50. ________________________________________ (11) 21835 Consulter le mémoire (51) E21B 17/00 (2018.01); E21B 17/042 (2018.01) ; F16L 15/04 (2018.01) (21) 1202300427 - PCT/JP2022/016384 (22) 31/03/2022 (30) JP n° 2021-075844 du 28/04/2021 (54) Steel pipe for oil well. (72) OSHIMA, Masahiro (JP) et KIMOTO, Masanari (US) (73) 1-Nippon Steel Corporation, 6-1, Marunouchi 2-chome, Chiyoda-ku, TOKYO 1008071 (JP) et 2-Vallourec Oil And Gas France, 54 rue Anatole France, AULNOYE-AYMERIES 59620 (FR) (74) Cabinet Spoor & Fisher Inc. Ngwafor & Partners, The House of Gideon, Golf/Bastos Quater, Opposite The American Embassy, Entrance-Saint John Paul II Boulevard, P.O. Box 8211, YAOUNDE (CM). (57) An oil-well steel pipe including a Zn-Ni alloy plating layer that has excellent galling resistance is provided. An oil-well steel pipe according to the present disclosure includes: a pipe main body that includes a pin which includes a pin contact surface, and a box which includes a box contact surface; and a Zn-Ni alloy plating layer which is formed on at least one of the pin contact surface and the box contact surface. The chemical composition of the pipe main body contains, in mass%, C: 0.01 to 0.60%, Cr: 0 to 8.0% and Fe: 80.0% or more. In addition, when a region containing C in an amount that, in mass%, is 1.5 times or more greater than the C content of the pipe main body is defined as a C-concentrated layer, the thickness of the C-concentrated layer in the wall thickness direction of the pipe main body is within the range of 0 to 1.50 µm.
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