Seamless Steel Pipe Manufacturer & Global Exporter in China
China leading ISO 9001, API 5L, and CE certified direct manufacturer and exporter of hot-rolled and cold-drawn Carbon Steel Seamless Pipes. Covering ASTM A106 Gr.B, ASTM A53 Gr.B, API 5L Gr.B to X70 PSL1/PSL2, and ASTM A333 Grade 6 low-temperature pipes. Thickness from SCH 20 to SCH 160 & XXS. Standardized with 100% Hydrostatic and Ultrasonic testing for high-pressure boilers, oil & gas transport, petrochemical refineries, and structural projects worldwide.
Figure: Precision Beveled End Hot-Rolled Seamless Steel Pipes (ASTM A106 Gr.B / API 5L PSL2) Ready for Export Packing
1. Seamless Steel Pipe Technical Specification & Schedule Wall Matrix
Sino East Steel supplies full-range heavy industrial seamless pipes manufactured via high-precision hot-piercing and cold-drawing processes. All pipes strictly conform to international ASTM, ASME, API, and DIN/EN standards with certified Mill Test Certificates (MTC EN 10204 3.1 / 3.2).
| Standard & Specification | Available Steel Grades | Outer Diameter (OD) | Wall Thickness (Schedule) | Primary Industrial Application |
|---|---|---|---|---|
| ASTM A106 / ASME SA106 | Grade B, Grade C | 1/2″ – 24″ (21.3mm – 610mm) | SCH 20, SCH 40, SCH 80, SCH 160, XXS | High-temperature boilers, refinery piping & steam lines |
| API 5L Seamless Line Pipe | Gr.B, X42, X52, X60, X65, X70 (PSL1/PSL2) | 1/2″ – 28″ (21.3mm – 711mm) | SCH 40 to SCH 160, STD, XS, XXS | Onshore & offshore crude oil, natural gas & slurry transit |
| ASTM A53 / ASME SA53 | Grade A, Grade B (Type S Seamless) | 1/8″ – 24″ (10.3mm – 610mm) | SCH 10 to SCH 80, STD, XS | Mechanical, structural, water, gas & pressure piping |
| ASTM A333 Low Temp | Grade 6, Grade 3 | 1/2″ – 24″ (21.3mm – 610mm) | SCH 40, SCH 80, SCH 160 | Cryogenic & low-temperature service down to -45°C |
| DIN 17175 / EN 10216-2 | St35.8, St45.8, 15Mo3, 13CrMo44 | 21.3mm – 508mm | 2.0mm – 40mm | European standard thermal engineering & heat exchangers |
2. ANSI / ASME B36.10M Seamless Pipe Dimensions & Wall Schedule Guide
Below is our standard dimensional reference for nominal pipe sizes (NPS) frequently exported for engineering tenders, EPC contractors, and stockist distributors:
| NPS (Inch) | OD (mm) | SCH 20 (mm) | SCH 40 / STD (mm) | SCH 80 / XS (mm) | SCH 160 (mm) | XXS (mm) | Weight (kg/m SCH40) |
|---|---|---|---|---|---|---|---|
| 1/2″ (DN15) | 21.3 | – | 2.77 | 3.73 | 4.78 | 7.47 | 1.27 |
| 1″ (DN25) | 33.4 | – | 3.38 | 4.55 | 6.35 | 9.09 | 2.50 |
| 2″ (DN50) | 60.3 | – | 3.91 | 5.54 | 8.74 | 11.07 | 5.44 |
| 4″ (DN100) | 114.3 | – | 6.02 | 8.56 | 13.49 | 17.12 | 16.07 |
| 6″ (DN150) | 168.3 | – | 7.11 | 10.97 | 18.26 | 21.95 | 28.26 |
| 8″ (DN200) | 219.1 | 6.35 | 8.18 | 12.70 | 23.01 | 22.23 | 42.55 |
| 12″ (DN300) | 323.8 | 6.35 | 10.31 | 17.48 | 33.32 | 25.40 | 79.73 |
3. Strict Quality Assurance: 100% Non-Destructive Testing (NDT)
Hydrostatic Pressure Testing
Every length of pipe is tested up to 100% of minimum specified yield strength (SMYS) with minimum 5-10 seconds dwell time to guarantee zero leakage under pressure.
Ultrasonic & Eddy Current NDT
Full-body online ultrasonic testing (UT) and eddy current examination detect internal cracks, laminations, and surface flaws according to API 5L & ASTM A106.
Third-Party Inspection & MTC
We support client-appointed third-party inspections (SGS, BV, Intertek, DNV, Lloyd’s Register) with 100% traceability to heat numbers and EN 10204 3.1/3.2 test certificates.
4. Mixed-Size Container Consolidation & Seaworthy Export Packing
One of Sino East Steel’s primary strengths for overseas contractors and importers is our mixed-size nesting consolidation service:
- Nesting Packaging: Smaller OD pipes nested inside larger OD pipes to maximize 20ft / 40ft container payload up to 26-28 metric tons, slashing CIF shipping costs by up to 25%.
- Surface Finishing: Black bitumen painting, anti-rust varnish, transparent oiling, or 3PE / FBE external anti-corrosion coating.
- End Protection: Plain ends (PE), Beveled ends (BE 30° / 37.5° for welding) protected with heavy-duty plastic end caps or recessed steel bevel protectors.
- Bundling: Hexagonal bundles tightly strapped with high-tensile steel bands (for OD ≤ 8″) and lifting slings for rapid dock discharge.
5. Frequently Asked Questions (FAQ) for Seamless Pipe Buyers
Q1: What is the main difference between ASTM A106 Grade B and ASTM A53 Grade B Seamless Pipes?
ASTM A106 is specifically engineered and certified for high-temperature and high-pressure service (e.g., steam boilers, refinery process lines up to 425°C), requiring strict silicon content and mandatory bend/flattening tests. ASTM A53 is designed for general mechanical, structural, and low-to-medium pressure fluid transport (water, gas, air).
Q2: What is the Minimum Order Quantity (MOQ) and delivery lead time for seamless steel pipes?
For standard stock sizes (ASTM A106 Gr.B / API 5L Gr.B SCH40/SCH80 from 1/2″ to 12″), our MOQ is 1 metric ton with immediate dispatch within 5-7 days. For custom wall thicknesses or non-standard lengths, MOQ is typically 1 full 20ft container (approx. 20-25 MT) with a 20-25 day production cycle.
Q3: Can Sino East Steel provide MTC EN 10204 3.2 certification with third-party stamping?
Yes. We routinely cooperate with SGS, Bureau Veritas (BV), Intertek, and DNV for witnessing chemical analysis, tensile testing, Charpy V-notch impact testing, and hydrostatic testing to issue official EN 10204 3.2 certificates for oil & gas projects in GCC, West Africa, and Southeast Asia.
Q4: What incoterms and trade payment terms do you support?
We offer flexible commercial terms including FOB Tianjin / Qingdao / Shanghai, CFR, and CIF to major global ports (Jebel Ali, Dammam, Lagos Apapa, Tema, Abidjan, Jakarta, etc.). Payment methods include T/T and 100% Irrevocable Letter of Credit (L/C at sight) from prime international banks.
Seamless Pipe Production: Rotary Piercing to Final Testing
Seamless steel pipe from our mill starts as a solid round billet, pierced at high temperature and progressively rolled through the mandrel mill before sizing, straightening and finishing. Because there is no longitudinal weld, the pipe offers uniform strength around the circumference - the reason seamless is specified for pressure service in refineries, boilers and oilfield flowlines.
The billet source is controlled: we buy billets only from integrated steelmakers and keep the billet certificates in the quality file, so every finished pipe can be traced back to its heat. After rolling, the pipe passes through heat treatment where required, then eddy-current inspection and hydrostatic testing before cutting and end preparation.
Service Conditions and Grade Selection
- ASTM A106 Grade B - the standard choice for high-temperature process piping
- API 5L Grade B to X70 - seamless line pipe for oil and gas gathering and transmission
- Chinese grades 20#, 45#, 16Mn - economical options for structural and mechanical service
- End preparation - plain, beveled or threaded ends per project specification
For boiler and exchanger tube programs we can supply to the exact OD/wall combination and length schedule, with positive material identification and full traceability documentation.