Seamless Tubing and Couplings Hydrosulfide-Carbon Dioxide- and Cold-Resistant

Steel seamless tubing as per this TU has enhanced corrosion resistance and is cold-resistant up to temperature -50C.

The general corrosion rate for metal of tubing, couplings and strengthened connection parts is not more than 0.5 mm/year.

The tubing is made in two versions:
1. Plain tubes with couplings per GOST 633-80;
2. Tubes completed with strengthened connection parts.

The tubes are manufactured with strength groups Ks, Es, Ls with range as per GOST 633-80.

The range of tubing with couplings is specified by Table 1.1.

DN (nominal diam.) of pipe, mm

Tube wall thickness, mm

Tube type

Plain, without thread

Plain, with triangular thread

60

5,0

Ks, Es, Ls

Ks, Es, Ls

73

5.5 : 7.0

Ks, Es, Ls

Ks, Es, Ls


The range of tubing with strengthened connection parts is specified by Table 1.2.

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

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 and couplings are manufactured from tube shell made from steel 30 FB, 30 KhF and 30 KhMFBA.

Mechanical properties of tubes and couplings are specified by Table 1.3.

Parameter description

Nominal value of parameter for steel of strength group:

s

s

Ls

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

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

98 HRB

Elongation, δ5, %,
not less than

18

16

15

Impact strength at Charpy specimens,
J/cm
2(kgcm/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 connection parts (interlocks).
The couplings and subs of wear-resistant interlocks are fabricated from steel 40 Kh, 40 KhFBA, and 40 KhMFBA 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/cm
2 (kgcm/mm2),
at test temperature -50C
not less than KCV-50C.

68,6 (7)

68,6 (7)

68,6 (7)



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