Oil-well metal pipe
An oil-well metal pipe according to the present disclosure includes: a pipe main body that includes a pin which includes a pin contact surface including an external thread part and which is formed at a first end portion, and a box which includes a box contact surface including an internal thread part and which is formed at a second end portion; 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 X-ray diffraction intensities of the Zn—Ni alloy plating layer satisfy Formula (1). I 18 / ( I 18 + I 36 + I 54 ) ≥ 0.6 ( 1 ) Here, in Formula (1), in units of cps, an X-ray diffraction intensity of {411} and {330} is substituted for I 18 , an X-ray diffraction intensity of {442} and {600} is substituted for I 36 , and an X-ray diffraction intensity of {552} is substituted for I 54 .
1. An oil-well metal pipe, comprising:
a pipe main body including a first end portion and a second end portion,
wherein
the pipe main body includes:
a pin formed at the first end portion; and
a box formed at the second end portion,
the pin includes:
a pin contact surface including an external thread part, and
the box includes:
a box contact surface including an internal thread part,
the oil-well metal pipe further comprising:
a Zn—Ni alloy plating layer formed on at least one of the pin contact surface and the box contact surface,
wherein X-ray diffraction intensities of the Zn—Ni alloy plating layer satisfy Formula (1):
I
18
/
(
I
18
+
I
36
+
I
54
)
≥
0.6
(
1
)
where, an X-ray diffraction intensity of {411} and {330} such that a sum of squares of the Miller indices becomes 18 is substituted, in units of cps, for I 18 in Formula (1); an X-ray diffraction intensity of {442} and {600} such that a sum of squares of the Miller indices becomes 36 is substituted, in units of cps, for I 36 in Formula (1); and an X-ray diffraction intensity of {552} such that a sum of squares of the Miller indices becomes 54 is substituted, in units of cps, for I 54 in Formula (1).
2. The oil-well metal pipe according to claim 1 , wherein
a thickness of the Zn—Ni alloy plating layer is within a range of 5 to 25 μm.
3. The oil-well metal pipe according to claim 1 , further comprising:
a lubricant coating on or above the Zn—Ni alloy plating layer.
4. The oil-well metal pipe according to claim 2 , further comprising:
a lubricant coating on or above the Zn—Ni alloy plating layer.