Our Large Diameter Straight Seam Welded Pipe is engineered to meet the strict standards wholesale clients demand-specifically API 5L (for oil and gas) and EN 10219 (for structural use). These standards aren't just paperwork; they're the reason your clients can trust the pipe for high-stakes projects like long-distance water pipelines or offshore platform structures.
We use high-strength low-alloy (HSLA) steel, with a minimum yield strength of 355 MPa and tensile strength of 490-630 MPa. Why does that matter? It means the pipe can handle extreme pressure-we tested a 12mm-thick pipe by subjecting it to 8 MPa of internal pressure for 24 hours, and it showed zero deformation. For wholesale buyers, this reliability cuts down on costly on-site failures.
Each pipe has a diameter range of 529mm to 2020mm (we can customize up to 3000mm) and length options from 3m to 18m. The straight seam is welded using double-sided submerged arc welding (SAW), which creates a weld strength 90% of the base metal-we verify this with X-ray and ultrasonic testing on every weld, ensuring no hidden cracks. We also offer 3PE anti-corrosion coating (peel strength ≥ 70 N/cm) that we tested in salt spray for 4000 hours with no rust. Whether your clients need it for energy transport or construction, our Large Diameter Straight Seam Welded Pipe delivers the consistency they need to win projects.
we use a CNC plate bending machine to shape the steel plates into a cylindrical form (with a circumference tolerance of ±1mm). The machine uses 16 hydraulic rollers to ensure the pipe stays perfectly straight-no bowing, which is critical for long pipeline runs. Then, we fix the straight seam with tack welding before moving to double-sided SAW: the first weld is done from the inside, then the pipe is flipped for the outside weld, with temperature controlled at 280-320°C to avoid brittleness.
After welding, we heat-treat the pipe in a 920°C furnace (holding for 1 hour, then cooling at 5°C per minute) to relieve internal stress. We then cut the pipe to length with a plasma cutter (accuracy ±2mm) and do a hydrostatic test-filling each pipe with water and pressurizing to 1.5 times the working pressure for 10 minutes. If it leaks, we scrap it. Finally, we coat and package each Large Diameter Straight Seam Welded Pipe with a foam sleeve and steel cradle, so it arrives scratch-free.
Right now, we have 3 production lines dedicated to Large Diameter Straight Seam Welded Pipe, each with a daily output of 20-30 pipes (depending on diameter). That adds up to a monthly capacity of 2400-3600 meters, or 1400-2100tons.
We keep 5000 tons of steel plates in our warehouse, so we never wait for raw materials. We also have a dedicated logistics team that works with shipping companies specializing in oversize cargo-we can arrange flat-rack container shipping or bulk transport to Europe and America, and we handle all export documents (like CE certificates and material test reports) to avoid customs delays.
Over the past 3 years, we've maintained a 99.1% on-time delivery rate. We also offer rush order support-if your client needs pipes in 1 week, just let us know, and we'll reallocate production resources. No order is too big or too urgent here-we treat every wholesale request as a priority.
We don't just sell Large Diameter Straight Seam Welded Pipe-we want to build long-term partnerships with our wholesale clients, so we make promises we can keep. First, a 12-year warranty on the anti-corrosion coating and 5-year warranty on the pipe itself:This aligns with EU consumer protection laws, so your clients feel secure.
Second, full transparency on quality: every batch comes with a detailed test report, including weld strength data, pressure test results, and coating thickness measurements-signed by our ISO 9001-certified quality team.
Third, flexible terms for wholesale buyers: we offer 25% advance, 75% balance after delivery (L/C, T/T, or open account for)
Frequently Asked Questions
Q: Do you support OEM or ODM?
A: Of course! We welcome OEM and ODM cooperation, have a professional technical team, and can customize production according to your drawings or specific needs.
Q: Can you arrange transportation?
A: Yes. We have long-term cooperation with experienced sea and rail freight forwarders, and can arrange the best transportation plan for you, with the fastest shipping date and efficient service, to help you save transportation costs.
Q: How long is your delivery time?
A: If there is spot, it is usually shipped within 7 days; if there is no stock, it usually takes about 15-20 days to complete production and prepare the stock.
Q: Can you provide samples?
A: We are happy to provide samples free of charge, but the freight must be borne by you.
