4 in Pipe Cap: Durable, Customizable, and Fast from China's Trusted Foundry
By David Lin | Senior Sourcing Advisor, Hebei Yuanda Trade Co., Ltd. | Published: January 2026
Looking for a reliable 4 in pipe cap that meets your industrial piping specifications? A 4 in pipe cap is a critical component for sealing pipe ends in water, oil, gas, and chemical systems. At Hebei Yuanda Trade Co., Ltd. (YD), we produce high-quality 4 in pipe caps in cast iron, aluminum, and stainless steel via sand casting, die casting, or lost wax casting. With 20 years of foundry expertise, ISO 9001 certification, and a 5,000 m² factory, we deliver caps that fit standard 4-inch NPT/BSP threads, pressure ratings up to 300 PSI, and fully customizable designs. No more leakage, no more long lead times—just a dependable seal for your project.
Why Sourcing a 4 in Pipe Cap Can Be Challenging
Import managers and sourcing agents often face these common frustrations when procuring pipe caps from overseas suppliers:
- Inconsistent quality – Caps that don’t seal properly, causing leaks and system failures.
- Long lead times – Delays in production and shipping disrupt project schedules.
- Limited customization – Standard sizes and materials that don’t fit unique piping requirements.
- Compliance gaps – Missing certifications (ISO, CE, ASTM) that could lead to regulatory issues in the US market.
- Communication barriers – Poor responsiveness and lack of technical support during the sourcing process.
YD’s 4 in Pipe Cap – Engineered for Reliability
Our 4 in pipe caps are manufactured using advanced foundry techniques under strict quality control. We eliminate the guesswork by offering:
- Material flexibility – Choose from ductile iron, gray iron, stainless steel (304/316), or aluminum. All materials meet ASTM A48, A536, or A351 standards.
- Precision dimensions – Threaded (NPT, BSP, BSPT) or socket-weld ends. Tolerances within ±0.5% of nominal size.
- Pressure ratings – Class 150, 300, 600 (up to 1000 PSI for stainless steel).
- Surface finishing – Hot-dip galvanizing, epoxy coating, or plain finish as per your requirement.
- 100% pressure testing – Each cap is hydrostatically tested before shipment.
Technical Specifications – 4 in Pipe Cap (Typical)
| Parameter | Available Options |
|---|---|
| Nominal Size | 4 inch (DN100) |
| Materials | Gray iron (ASTM A48), Ductile iron (ASTM A536), Stainless steel 304/316 (ASTM A351), Aluminum (A356) |
| Connection Type | NPT, BSP, BSPT threaded; socket weld; butt weld |
| Pressure Class | 150#, 300#, 600# (up to 1000 PSI for stainless) |
| Surface Finish | Plain, hot-dip galvanized, epoxy coated, FBE |
| Certifications | ISO 9001:2015, CE, ASTM, ABS (upon request) |
| Testing | Hydrostatic, X-ray, dye penetrant (as required) |
Note: Actual specifications may vary by order. Please refer to the final order confirmation.
Where a 4 in Pipe Cap Is Used
Our caps are suitable for a wide range of industries:
- Oil & Gas – Sealing off unused branches in pipeline manifolds.
- Water & Wastewater – Capping ends of water mains or treatment lines.
- Chemical Processing – Isolating sections of piping for maintenance or safety.
- Construction – Temporary or permanent closure of piping in HVAC or fire suppression systems.
- Shipbuilding – Marine-grade stainless steel caps for ballast and fuel lines.
Why Choose Hebei Yuanda Trade Co., Ltd.?
Established in 2006, YD has become a preferred partner for US buyers seeking cast metal products. Our factory covers 5,000 m² and employs over 80 skilled workers. Key advantages:
- Quality Assurance – ISO 9001 certified. Third-party inspection (SGS, BV) is always welcome.
- OEM/ODM Design – Custom dimensions, threads, logos, and packaging available. Send us your drawing.
- High-Speed Delivery – Standard lead time 20-30 days. Express production in 10 days for urgent orders.
- MOQ – Low MOQ: only 50 pieces for stock sizes; 200 pieces for custom designs.
- Payment Terms – T/T, L/C, PayPal (for samples).
- Packaging & Logistics – Individually wrapped, wooden pallets or crates, with FOB/CIF shipping from Tianjin or Qingdao port.
- After-Sales – 12-month warranty against manufacturing defects. Replacement or refund guaranteed.
What Our Customers Say About YD 4 in Pipe Caps
"We’ve ordered over 2,000 pieces of 4 in pipe caps from YD for our water treatment plants. The threading is consistent and the caps hold pressure perfectly. Communication with Ben was excellent – he understood our specs from day one."
– Michael R., Procurement Manager, Midwest Water Solutions, USA
"As a brand owner, I need OEM caps with my logo and custom packaging. YD delivered exactly what we designed – the stainless steel 4 in caps look great and seal tight. Fast turnaround, even during peak season."
– James T., CEO, Precision Piping Solutions, Texas
"I was skeptical about sourcing from China, but YD’s quality control impressed me. They provided mill certificates and photos before shipping. The 4 in ductile iron caps met ASTM A536 perfectly. Will reorder."
– David K., Sourcing Agent, Industrial Supply Group, California
"We needed 4 in pipe caps in aluminum for a low-pressure air system. YD’s team suggested an epoxy coating for corrosion resistance – a great value add. Delivery was on time, and the pricing was very competitive."
– Linda S., Owner, AirFlow Components LLC, Florida
Comparison: Why YD Caps Stand Out
| Feature | Typical Supplier | Hebei Yuanda (YD) |
|---|---|---|
| Material Certification | Often not provided | Included with every batch (ASTM/EN) |
| Custom Threads | Limited to NPT only | NPT, BSP, BSPT, or custom thread forms |
| Lead Time (first order) | 45-60 days | 20-30 days (10 days express) |
| Minimum Order Quantity | 500-1000 pieces | 50-200 pieces |
| After-Sales Support | Limited | 12-month warranty, replacement guaranteed |
David Lin
Senior Sourcing Advisor – Hebei Yuanda Trade Co., Ltd.
With over 12 years in the metal casting industry, David has helped more than 200 US and European buyers source high-quality pipe fittings, flanges, and custom castings. He specializes in bridging the gap between technical requirements and cost-effective manufacturing.
Ready to Order Your 4 in Pipe Caps?
Contact us today for a free quote, technical datasheet, or sample request. Our team responds within 24 hours.
Email: info@ydcastings.com
Tel: +86-311-808-126-83 | WhatsApp: +8619333738338 (Ben) / +8619333736198 (Linda)
All product specifications are for reference only. Please confirm details in your order contract.
