Drill string sub
The sub is made with a different combination of connecting threads, depending on the required size from 45 to 426 mm.
Subs All types are available with right and left connecting threads of a cylindrical configuration and speed, as well as the connecting threads of special purpose drawings agreed with the customer.
Depending on the magnitude of the loads acting on the sub, the corresponding strength group is provided in the manufacture of the sub. The load with a safety factor of n = 1.0 is allowed according to special plans agreed with the Gosgortekhnadzor.
Group 1 - meets the requirements of GOST 7360-82 and is provided by the use of steel 40XH GOST 4543-7 1;
Group 2 - meets the requirements of API-7 for drill pipe tool joints and is ensured by the use of steel 40XH2MA GOST 4543-7 1;
Group 3 - meets the requirements for highly loaded sub of horizontal wells and sidetracks, and is ensured by the use of steel 38XH3MFA GOST 4543-71 .
Parameter | Norm of mechanical properties of strength | ||
one | 2 | 3 | |
Temporary tear resistance, MPa, not less | 882 | 970 | 1020 |
Yield strength, MPa, not less | 735 | 830 | 880 |
Relative elongation,%, not less | 10 | thirteen | fifteen |
Relative narrowing,%, not less than | 45 | 45 | fifty |
Impact strength, KVC J / cm 2, not less than | 68.5 | 70 | one hundred |
Brinell hardness, HB | 285 ... 341 | 285 ... 341 | 272..315 |
The absence of internal and surface defects of the sub is ensured by the implementation of ultrasonic and capillary control. At the request of the customer, a diagram of permissible operational and maximum loads is attached to the passport to the sub.