Premium range of galvanized coils, structurally engineered pipes, and standard steel profiles exported globally.
In structural engineering and heavy fluid transmission, the designation 250NB (Nominal Bore) corresponds directly to an outer diameter standard of approximately 273.1 mm (10 inches). Choosing the right schedule size and structural grade is critical for industrial applications, ensuring safety and compliance across global infrastructure projects.
As a leading Chinese supplier, Tianjin Minjie Steel delivers comprehensive 250NB piping systems manufactured through Electric Resistance Welding (ERW) and Hot-Dip Galvanization processes, conforming strictly to ASTM, BS, DIN, and JIS requirements. Depending on project demands, we provide varied wall thicknesses ranging from Schedule 20 up to Schedule 80 to withstand precise hydraulic pressures and load limits.
For standard DN250/250NB carbon steel piping, the nominal dimensions must be carefully calculated against load limits. Outside diameter defaults at 273.1 mm, with nominal wall thicknesses spanning from Light (Medium-light scaffolding grades) to heavy industrial line-pipe grades (up to 12.7mm wall thickness).
| Nominal Size (NB) | Metric DN Equiv. | Outside Dia. (OD) | Standard Wall (Sch 40) | Weight (Plain End) |
|---|---|---|---|---|
| 250NB | DN 250 | 273.1 mm | 9.27 mm | 60.31 kg/m |
| 250NB (Light) | DN 250 | 273.0 mm | 6.35 mm | 41.77 kg/m |
| 250NB (Extra Strong) | DN 250 | 273.1 mm | 12.70 mm | 81.63 kg/m |
Established in 1998, Tianjin Minjie Steel Co., Ltd has built a legacy of trust and engineering excellence over the past 25 years. Our massive manufacturing plant spans more than 70,000 square meters, strategically situated just 40 kilometers from Xingang Port (Tianjin)—the most vital shipping hub in Northern China. This prime geographic location ensures exceptionally streamlined logistics and fast international dispatch speeds.
As an industry-certified manufacturer and exporter of structural steel products, we have applied for and received 3 structural patents, focusing on groove pipes, shoulder pipes, and victaulic connections. Our premium line of products includes hot-dip galvanized steel pipes, pre-galvanized pipes, ERW hollow structural sections, and versatile scaffolding frameworks, all certified under the ISO9001:2015 quality management system.
Advanced Production Capacity: Our production line is powered by 4 high-efficiency pre-galvanized product lines, 8 precision ERW steel pipe lines, and 3 advanced hot-dipped galvanized processing lines. The annual output across our industrial lines exceeds 300,000 metric tons of structural and pressure-grade steel tubes.
We design and manufacture structural systems with high E-E-A-T values, trusted by clients across major world economies.
In September 2019, our technical team visited key engineering projects in Singapore. Our high-precision grooved and standard structural pipes were highly praised for complying with the local building standards.
In 2019, Korean industrial engineers toured our Tianjin factory with custom drawings, establishing a direct supply chain agreement for specialized machinery pipes.
A long-term Australian procurement agency returned to audit our facilities in November 2018, reinforcing our partnership and expanding our supply scope for structural safety piping.
In 2019, Indian structural developers visited multiple factories in China and chose Tianjin Minjie, signing an immediate monthly contract of 10 standard containers.
In June 2017, partners from Lebanon completed a structural review of our facility and placed an immediate order of 1,000 tons of hot-dipped structural tubes.
Having met initially at the Canton Fair in 2018, Saudi energy pipeline buyers audited our hot-dipped zinc lines, leading to a long-term supply agreement.
Our presence at the annual Canton Fair remains a central channel for international collaboration. By showcasing actual sample dimensions, demonstrating zinc layer uniformity, and explaining our patent-derived grooves, we invite developers to experience our factory firsthand in Tianjin. Statistically, more than 80% of our on-site Canton Fair visitors schedule factory tours to cement formal supply channels.
Global demand for 250NB steel pipes is undergoing a shift toward high-performance coating technologies and modular pre-fabricated connectors. Industrial projects in regions like Southeast Asia, Australia, and the Middle East are increasingly mandating environmental sustainability and longer lifecycle spans. Key market trends include:
To address these demands, Tianjin Minjie provides full metallurgical reports and ultrasonic test logs. Our in-house quality controllers check every production batch to verify the mechanical characteristics and guarantee seamless fit-up onsite.
Innovating high-durability steel and coating technologies to withstand complex global weather environments.
We utilize enclosed acid regeneration loops and low-fume zinc kettles to satisfy stringent national carbon emissions standards, ensuring export reliability into European and American markets.
Applying solid-state induction welders to yield highly stable seams. We perform continuous electromagnetic non-destructive testing (NDT) to secure high fluid-pressure integrity.
Our 3 registered engineering patents target groove, shoulder, and victaulic connections, reducing assembly errors and pipeline installation labor costs by up to 40%.
Clear, expert-level insights to support engineering choices and procurement decisions.
High-quality carbon steel tubes, square profiles, prepainted coils, and reinforcing wire products manufactured for industrial supply chains.
Minjie Steel