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API Casing Coupling
Unionlever supplies full-range API-certified couplings for casing, tubing, and line pipe applications. Manufactured in strict compliance with API Specification 5CT and API 5B, our couplings ensure perfect thread integrity, pressure sealing, and dimensional accuracy for critical downhole connections.
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Casing & Cementing
Unionlever OFS supplies full-range API-certified OCTG couplings for casing and tubing string connections. Manufactured in compliance with API Specification 5CT and threaded per API Spec 5B, our couplings are designed to deliver reliable thread integrity, pressure sealing, and dimensional accuracy for critical downhole well construction.
We supply casing and tubing couplings covering common API thread forms and lengths, supporting both project procurement and routine replacement needs.
- Casing Couplings (API 5CT): STC / LTC / BTC (Buttress Thread)
- Tubing Couplings (API 5CT): NU / EU (EUE) / integral joint matching
- Line Pipe Couplings (where applicable): threaded types for flowlines
- End finish: phosphate coating, thread protectors (plastic/steel)
- Documents available: MTC, hardness report, dimensional and thread inspection records (project-based)
- API 5CT / API 5B compliance for standardized interchangeability
- Precision machining ensures stable makeup and consistent seal performance
- Thread integrity controlled by thread gauging and dimensional checks
- Grades available: H40, J55, K55, N80, L80, C90, T95, P110 (Q125 available upon request)
- Supports global delivery via Qingdao supply chain coordination (export-ready packing)
- Surface / intermediate / production casing strings
- Production tubing strings and completion programs
- Onshore and offshore well construction projects requiring standardized OCTG connections
Product Series Overview
| Series | Standard | Primary Types | Typical Application |
|---|---|---|---|
| Casing Couplings | API 5CT | STC (STD), LTC (LINE), BTC (BUTT-THREAD) | Surface, Intermediate, Production Casing |
| Tubing Couplings | API 5CT | NU, EU (EUE), Integral Joint | Production Tubing Strings |
| Line Pipe Couplings | API 5L | Threaded | Flowlines & Transmission Pipelines |
General Technical Parameters
| Parameter | Specification |
|---|---|
| Compliance Standard | API Specification 5CT, API Spec 5B |
| Thread Type | API Round Thread (STC & LTC), API Buttress Thread (BTC) |
| Size Range | Common coverage from 4-1/2" to 20" (confirm by OD & weight) |
| Material Grade | H40, J55, K55, N80, L80, C90, T95, P110, Q125 (upon request) |
| End Finish | Phosphate Coating, Plastic/Steel Thread Protectors |
| Inspection | 100% Dimensional Check, Thread Gauging, Hardness Test |
| Marking | Heat No., Size, Grade marking; API stamping available per requirement |
Each batch can be supplied with documentation to support field acceptance and traceability, including: Material Certificate (MTC), Hardness Report, Thread Inspection Records, and Dimensional Test Reports. Additional third-party inspection can be coordinated upon request.
For projects requiring mixed sizes or staged deliveries, Unionlever OFS supports stock review, packing consolidation, and export marking coordination. Replacement couplings can be supplied in bulk packing or customer-specified packing standard with protectors to prevent thread damage.
- Type: casing coupling / tubing coupling
- OD & Weight: e.g., 9-5/8" 53.5#
- Grade: e.g., J55 / N80 / L80 / P110
- Thread Type: STC / LTC / BTC (or NU / EU for tubing)
- Quantity and destination port
- Any special requirement: API stamping, packing standard, third-party inspection
Providing complete details helps us confirm compatibility quickly and reduce back-and-forth, enabling faster quotation and delivery planning.
Unionlever OFS focuses on correct selection + project coordination for OCTG connections. By confirming OD/weight, grade, and thread type upfront, we help reduce mismatch risk and avoid costly delays on site.
We support small-batch trial orders, mixed-size consolidation, and export-ready packing to match real procurement workflows.
Frequently Asked Questions
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Contact Phone
Contact Email
sales@unionleverofs.com
ofs@unionlever.com
Warehouse & Shipping
Our inventory, warehouse operation, packaging, and loading procedures ensure safe, fast, and reliable delivery worldwide.
Related Products
Building upon more than a decade of field experience, Unionlever OFS offers a comprehensive portfolio covering downhole drilling tools, fishing tools, handling tools, well control equipment, cementing tools, and solid-control systems.
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Unionlever Oilfield Equipment Co., Limited
A Member of
Unionlever International Group Limited
(Established Since 2010)
"To be a globally trusted leader in oilfield equipment and integrated supply solutions."
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