1. Main Technical Parameters
The 2 in x 2 in 105 MPa Plug Valve is used in oilfield wellheads, Christmas trees and high-pressure fluid manifold systems for opening, closing and isolation of high-pressure media. This technical article follows the Chinese page and summarizes pressure-bearing performance, sealing performance, bore and thread accuracy, key pressure-containing material properties, NDT and quality control.
| Item | Technical Information | Remarks |
|---|---|---|
| Product name | Plug Valve | High-pressure wellhead/manifold control valve |
| Model | 2 in x 2 in, 105 MPa | Model in historical inspection data |
| Reference standards | API Spec 6A; SY/T 5127-2002 | With product drawings |
| Hydrostatic strength test | 155.2 MPa | Staged pressure holding; no visible leakage |
| Seat sealing test | 105 MPa | Both ends tested separately |
| Bore gauge | Dia. 45.20 mm (+0.68/0) x 76 mm | Gauge passed freely |
| Connection thread | 4.125-3-Acme-2G | Go/no-go gauge inspection qualified |
| Main materials | Body 35CrMo; plug 35CrMoA | Alloy structural steel |
| NDT | UT and MT | Key parts accepted |
2. Inspection Basis and Quality Conclusion
Historical inspection records show that this Plug Valve was inspected according to API Spec 6A, SY/T 5127-2002 and the applicable product drawing. The inspection scope covered hydrostatic strength, seat sealing, bore, connection thread, material chemistry, mechanical properties after heat treatment, hardness, ultrasonic testing, magnetic particle testing, appearance, coating, marking and supplied documents. The recorded conclusion is that all inspected items met the applicable requirements.
3. Pressure, Sealing and Bore Performance
For the hydrostatic strength test, pressure was raised to 155.2 MPa, held for 3 minutes, released to zero, raised again to 155.2 MPa and held for 15 minutes. No visible leakage was found.
For the seat hydrostatic sealing test, the left and right ends were tested separately at 105 MPa. After the first 3-minute hold and depressurization, pressure was raised again to 105 MPa and held twice for 15 minutes. No visible leakage was found at either end.
A bore gauge with diameter 45.20 mm (+0.68/0) and length 76 mm passed freely, confirming that the flow bore met the technical requirement.
4. Thread, Materials and NDT
The connection thread is 4.125-3-Acme-2G. Go/no-go gauge inspection showed that the go gauge passed and the no-go gauge entered by about 1/4 turn, meeting the technical requirement.
The valve body is 35CrMo. Recorded mechanical results after heat treatment include tensile strength 690 MPa, yield strength 565 MPa, elongation 16%, reduction of area 22%, impact absorbed energy 35 J at -46°C and hardness 272 HB. The plug is 35CrMoA, with tensile strength 700 MPa, yield strength 575 MPa, elongation 16%, reduction of area 22%, impact absorbed energy 32 J at -46°C and hardness 276 HB.
The body and plug were inspected by ultrasonic testing and magnetic particle testing. The recorded NDT results met the relevant acceptance requirements.
5. Appearance, Marking and Documents
Exposed surfaces should be flat with smooth transitions, and the coating should be bright and uniform without defects that affect appearance or protection. Marking should identify performance level, product specification level, rated working pressure, temperature class, material class, end connection thread, manufacturing date and manufacturer name or mark. Supplied technical documents should be complete and protected against moisture and corrosion for transport, storage and field use.