Carbon Steel Pipe Cap — Factory Direct Supplier | Huaxia-Steel
Carbon steel pipe caps are essential fittings used to seal the ends of piping systems, protecting pipe threads and preventing contamination during storage and transport. As a factory-direct supplier, Huaxia-Steel manufactures pipe caps to ASME B16.11, MSS-SP-95, and DIN standards, covering sizes from 1/8″ to 4″ in threaded and socket-weld configurations. Our caps are produced from ASTM A105, A234 WPB, and ST37/ST35.8 materials with full EN 10204 3.1 certification, serving oil & gas, petrochemical, and industrial piping applications worldwide.
Product Overview
Pipe caps (also called end caps or pipe plugs) are designed to close the end of a pipe, fitting, or flange. They are available in two primary connection types: threaded (NPT or BSPT) and socket-weld. Threaded caps screw onto the external pipe threads, while socket-weld caps are fillet-welded to the pipe for a permanent, leak-proof seal. Carbon steel pipe caps are preferred for their strength, pressure rating, and cost-effectiveness compared to stainless steel alternatives.
Huaxia-Steel’s pipe caps are forged from high-quality carbon steel bar stock, ensuring uniform grain structure and mechanical properties. Each cap undergoes 100% visual inspection and dimensional verification before packaging. Threaded caps are machined to ASME B1.20.1 NPT standards with thread gauges verifying taper and pitch accuracy.
Specifications & Dimensions
Threaded Pipe Caps — ASME B16.11
| NPS (in) | DN (mm) | Cap Length (mm) | Cap Dia (mm) | Approx Weight (kg) |
|---|---|---|---|---|
| 1/8 | 6 | 25 | 18 | 0.03 |
| 1/4 | 8 | 29 | 22 | 0.05 |
| 3/8 | 10 | 33 | 25 | 0.07 |
| 1/2 | 15 | 38 | 32 | 0.12 |
| 3/4 | 20 | 41 | 38 | 0.17 |
| 1 | 25 | 44 | 48 | 0.27 |
| 1-1/4 | 32 | 48 | 57 | 0.40 |
| 1-1/2 | 40 | 51 | 64 | 0.54 |
| 2 | 50 | 56 | 76 | 0.81 |
| 2-1/2 | 65 | 60 | 92 | 1.30 |
| 3 | 80 | 64 | 108 | 1.95 |
| 4 | 100 | 68 | 140 | 3.50 |
Socket-Weld Pipe Caps — ASME B16.11
| NPS (in) | DN (mm) | Cap Length (mm) | Socket Depth (mm) | Bore (mm) |
|---|---|---|---|---|
| 1/2 | 15 | 25 | 9.5 | 21.3 |
| 3/4 | 20 | 25 | 12.5 | 26.7 |
| 1 | 25 | 29 | 12.5 | 33.4 |
| 1-1/4 | 32 | 30 | 12.5 | 42.2 |
| 1-1/2 | 40 | 32 | 12.5 | 48.3 |
| 2 | 50 | 38 | 16.0 | 60.3 |
| 2-1/2 | 65 | 41 | 16.0 | 73.0 |
| 3 | 80 | 44 | 16.0 | 88.9 |
| 4 | 100 | 48 | 19.0 | 114.3 |
Available Grades & Materials
| Grade | Standard | Yield (MPa) | Tensile (MPa) | Service Temperature |
|---|---|---|---|---|
| A105 | ASTM A105 | 205 | 485 | −29°C to +425°C |
| A234 WPB | ASTM A234 | 240 | 415 | −29°C to +425°C |
| ST37 | DIN 1629 | 235 | 360–510 | −10°C to +400°C |
| ST35.8 | DIN 17175 | 235 | 360–480 | −10°C to +400°C |
| 20# | GB/T 699 | 245 | 410 | −20°C to +425°C |
Manufacturing Standards
- ASME B16.11: Forged Steel Fittings, Socket-Welding and Threaded
- MSS-SP-95: Swaged Nipples and Bull Plugs
- MSS-SP-79: Socket-Welding Reducer Inserts
- DIN 2982: Threaded Pipe Plugs (German standard)
- BS 3799: Steel Pipe Fittings, Screwed and Socket-Welded (British standard)
- GB/T 14383: Forged Steel Socket-Welding and Threaded Fittings (Chinese standard)
Applications
- Oil and gas pipeline terminations and test points
- Petrochemical process piping systems
- Water treatment and distribution networks
- Steam and condensate piping
- Instrumentation and impulse line connections
- Pressure vessel nozzle closures
- Temporary pipe closures during construction and hydrotesting
Quality Assurance
Every production batch of pipe caps undergoes the following quality control procedures:
Packaging & Shipping
- Standard packaging: wooden cases with inner polyethylene lining
- Small sizes (1/8″–1″): bulk in bags, then boxed (approx 500–2000 pcs/box)
- Large sizes (2″–4″): individually wrapped, then palletized
- Each package marked with: size, grade, standard, quantity, heat number, PO number
- Export wooden pallets: ISPM-15 heat-treated, suitable for international shipping
- VCI anti-corrosion paper available for sea freight shipments
- Container loading: photos and loading plan provided to buyer
Why Choose Huaxia-Steel for Pipe Caps?
- Factory-direct pricing: No trading company markup — save 15–25% on unit costs
- Full traceability: Every cap traceable from raw material heat number to finished product
- Flexible MOQ: From 500 pieces for standard sizes; custom sizes from 1,000 pieces
- Fast delivery: 15–25 days for standard sizes; 25–35 days for custom configurations
- Global export experience: Shipping to 80+ countries with proper documentation
Conclusion
Carbon steel pipe caps are a critical component in piping systems, providing reliable end closures for pressure-containing applications. Huaxia-Steel manufactures pipe caps to international standards with rigorous quality control and full material certification. Whether you need standard threaded caps for a maintenance project or custom socket-weld caps for a new pipeline, our factory-direct supply ensures quality, traceability, and competitive pricing. Contact us today for a quotation — we respond within 24 hours with detailed pricing and technical specifications.
