1. Structure: There is a deposition of tungsten alloy layer on the inner and outer walls of general API standard pipes or special premium thread tubing. 2. Performance Indicators
Tungsten Alloy Layer and Backing Material Binding Force: According to GB/T5270-2005 testing, the tungsten alloy layer does not crack or peel off.
Appearance: Uniformly bright, showing silvery white
Thickness of Tungsten Alloy Layer: 40-60μm
Hardness of Tungsten Alloy Layer: 560-640HV
Special Premium Thread Tubing: Hydrostatic pressure: 95MPa, load maintaining for 30 minutes, without leakage.
Gas seal: 70MPa, load maintaining for 15 minutes, without leakage.
| Test Item | Inspection Item | Test Content |
| Threaded connection performance | Makeup/breakout test | 4 makeup and 3 breakout, the optimal torque |
| Hydrostatic pressure test | 95MPa pressure maintaining for 95MPa 30 minutes |
| Air tightness test | ISO 13679 simplified B series test
Calculate the load point according to the load envelope determined
based on the wellhead load |
| Conclusion | The threaded connection performance fully meet the requirements of the test items |
3. Product Classifications and Standards
Standards of Tungsten Alloy Anti-corrosive Tubing
Indicators
Anti-corrosion Grade | Class A Tungsten Alloy Tubing | Class B Tungsten
Alloy Tubing | Class C Tungsten
Alloy Tubing |
| CO2 Partial Pressure of CO2 (Mpa) | ≤11Mpa | ≤5Mpa | ≤2Mpa |
| Partial Pressure of H2S (Mpa) | 5Mpa | 4Mpa | 2Mpa |
| Temperature (0C) | ≤1600C | ≤1200C | ≤900C |
| CL- concentration (g/L) | ≤120g/L | 80g/L-100g/L | ＜80g/L |
| Anticorrosion Comparison | Equivalent to nickel-based alloy | Better than super 13Cr or dual-phase steel | Better than 13Cr |
| Mechanical Property | Consistent with that of backing material | Consistent with that of
backing material | Consistent with that of
backing material |
| Backing Material (Seamless Steel Pipe) | 110SS | N80、P110 | J55、N80 |
| Thickness of Tungsten Alloy Layer | 60-80um | 40-60um | ≥30um |
