High Longevity Oil-Well Tubing and Interlocks of Production Strings for Corrosive Media

TU 1372-172-0147016-01

The tubing complete with wear-resistant interlocks per this TU is meant for regular operation in corrosive hydrosulfide media with parameters specified in Table 5 "Safety Regulations for Petroleum and Gas Industries".
Besides, the tubing has enhanced corrosion resistance at well treating with hydrochloric acid and is cold-resistant up to temperature -50C. The general corrosion rate for tubing metal is not more than 0.5 mm/year.

The range of tubes, subs and couplings is specified by Table 1.

Tube type DN (nominal diam.),
mm
Tube wall thickness,
mm
Outside Diameter of coupling and sub,
mm
Plain as per GOST 633-80 60
73
89
102
114
5.0
5.5 : 7.0
6.5 : 8.0
6.5
7.0
73.0
88.9
108.0
120.6
132.1


The tubes are manufactured in version A per GOST 633-80.
In coordination with client, the tubes can be manufactured with the length up to 11 meters.
The tubes are manufactured with strength groups Ks, Es, Ls from tube shell made from steel 40Kh, 40KhN, 40KhFBA and 40KhMFBA.

Mechanical properties of tubes are specified by Table 1.1.

Parameter description

Nominal value of parameter for steel of strength group:

Ks

Es

Ls

Tensile strength, σt, N/mm2 (kgf/mm2),
not less tha

647(66)

657(67)

755(77)

Yield strength, σy,
N/mm
2 (kgf/mm2),
not less than
not more than

519(53)
627(64)

549(56)
657(67)

647(66)
784(80)

Ratio σy/σt,
not more than

0.8

0.85

0.85

Rockwell hardness,
not more than

95 HRB

98 HRB

23 HRC

Elongation, δ5, %,
not less than

18

16

15

Impact strength at Charpy specimens, J/cm2 (kgf/mm2), at test temperature -50C
not less than KCV-50C.

98(10)

98(10)

98(10)

Share of ductile component (V) at test temperature -50C,
not less than

70

70

70



The tubing per this TU is completed with wear-resistant interlocks consisting of coupling and sub fabricated in accordance with TU 6846-109-07500303-01.
The couplings and subs of wear-resistant interlocks are fabricated from steel 40Kh, 40KhN, 40KhFBA and 40KhMFBA and subjected to ionic nitride hardening procedure. Using of interlocks provides increased service life of threaded connections.

Mechanical properties of couplings and subs are specified by Table 1.2.

Parameter description

Nominal value of parameter for steel of strength group:

Ks

s

Ls

Tensile strength, σt,
N/mm
2 (kgf/mm2),
not less than

687 (70)

689 (70,3)

758 (77,3)

Yield strength, σy,
N/mm
2 (kgf/mm2),
not less than

491 (50)

552 (56,2)

654 (66,8)

Elongation, δ5, %,
not less than

12

13

13

Impact strength at Charpy specimens, J/cm2 (kgcm/mm2),
at test temperature -50C
not less than KCV-50C.

98 (10)

98 (10)

98 (10)



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