Couplings (Class T)
Couplings include sucker rod coupling, reducing coupling and polished rod coupling. There are five specifications: 5/8", 3/4", 7/8", 1" and 1-1/8". All the couplings comply with API Spec 11B and SY/T5029 Standards. The couplings are made of high-quality carbon steel or alloy steel.
The internal threads at both ends of the sucker rod couplings are identical and they are used to connect sucker rods of the same size or sinker bar with sucker rod thread.
The internal threads at both ends of the reducing couplings are different and they are used to connect sucker rods of different sized or to link polished rod and sucker rod.
The internal threads at both ends of the polished rod coupling are identical (cone angle=9°), and they are used to connected polished rods or sinker rods with polished rod threads to sucker rods.
Normally, there are two wrench flats on the outer circle of couplings. But the wrench flats can be removed per clients' request. All couplings can be made into full size (FS) or slim hole (SH) specifications.
Specification| Material | Chemical Composition (wt.%) | |||||||||
| C | Mn | Si | Cr | Mo | Ni | V | S | P | Cu | |
| 45 (AISI 1045) | 0.42~ 0.50 | 0.50~ 0.80 | 0.17~ 0.37 | ≤0.25 | -- | ≤0.25 | -- | ≤ 0.035 | ≤ 0.035 | ≤0.25 |
| 35CrMoA (AISI 4135) | 0.32~ 0.40 | 0.40~ 0.70 | 0.17~ 0.37 | 0.80~ 1.10 | 0.15~ 0.25 | ≤0.30 | ≤ 0.07 | ≤ 0.025 | ≤ 0.025 | ≤0.20 |
| 40Cr (AISI 5140) | 0.37~ 0.45 | 0.50~ 0.80 | 0.20~ 0.40 | 0.80~ 1.10 | -- | -- | -- | ≤ 0.035 | ≤ 0.055 | ≤0.25 |
- Instead of cutting, the internal threads are extruded, with a neat surface and high strength.
- The hardness of the couplings is HRA58~62.
- The couplings have good performance on corrosion resistance and abrasion resistance.
- The internal and external surfaces are phosphatized to avoid thread adhesion in operation.
- If not requested, the couplings are made of high-quality cold-drawing steel.
