Description
Factory-direct seamless round pipes — OD 21.3–1420 mm and wall thickness up to 300 mm produced on our own cold-rolled seamless lines, shipped with full mill test certificates and third-party inspection reports.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Seamless Round Steel Pipe |
| Product Type | Seamless Round Steel Pipe / Seamless Round Hollow Section |
| Steel Grade | 10#, 20#, 35#, 45#, Q235, Q345, Q195, Q215, 16Mn, 40Cr, 15CrMo, 45Mn2, ASTM A53A/A53B, A178C, A106B, API 5L |
| Standard | API, ASTM, BS, DIN, GB, JIS |
| Section Shape | Round |
| Size Range | Outer Diameter 21.3–1420 mm |
| Wall Thickness | 2.11–300 mm |
| Length | 6 m / 6.4 m / 12 m (or as required) |
| Technique | Seamless (Cold Rolled) |
| Surface Treatment | Slightly Oiled / Cold Rolled |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Fluid transport, Boiler, Drill pipe, Hydraulic, Gas, Oil, Chemical fertilizer, Structure, Machinery parts, Automobile & tractor stress parts |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Oil & Gas | High-pressure transmission pipelines, drill pipe casings, wellhead flow lines |
| Power Generation | Boiler tubes, superheater elements, heat exchanger components |
| Heavy Machinery | Hydraulic cylinder barrels, crane boom sections, press frame columns |
| Automotive & Tractor | Drive shafts, axle housings, steering column tubes |
| Chemical Processing | Reactor feed lines, fertilizer plant piping, corrosive fluid transport |
| Structural Engineering | Machine base frames, equipment support columns, precision load-bearing members |
Where Dimensional Tolerance Decides Whether a Precision Order Passes Inspection
A ±1% tolerance on cold-rolled seamless tubes is the line between a batch that fits the hydraulic bore on arrival and one that gets rejected at the factory gate.
I have seen orders of cold-drawn precision tubes arrive at a machinery plant with wall variation exceeding acceptable limits — the honing process could not correct it, and the entire lot sat in the yard for weeks while the buyer argued with the supplier. For seamless round steel pipe used in hydraulic cylinders and boiler systems, even minor OD or WT deviation means re-machining costs that erase any price advantage gained at purchase. Grade confusion between GB 20# and ASTM A106B compounds the problem when mill test certificates do not clearly map chemical composition across standards [NEED_CITE: steel grade equivalence between GB, ASTM and API standards]. Sourcing from a single Seamless Round Steel Pipe Manufacturer with in-house testing eliminates the guesswork.
Matching Heavy-Wall Seamless Pipe to High-Pressure Engineering Demands
Cold-rolled seamless round hollow sections with wall thickness reaching 300 mm serve applications where internal pressure and structural load leave no room for weld-line uncertainty. The absence of a longitudinal seam makes these pipes the default choice for boiler systems, hydraulic cylinders, and oil country tubular goods. Our cold-rolled process holds ±1% dimensional tolerance across the full OD range of 21.3–1420 mm, ensuring that machined components meet bore specifications without secondary correction. Each Seamless Round Steel Pipe leaves the mill with an oiled surface to prevent transit corrosion — critical for bright-finish or precision-machined applications where surface pitting would force rejection.
Engineering Compliance and Certification Pathways Across Markets
Seamless round pipes destined for EU pressure equipment must conform to EN 10216 requirements, while North American oil and gas projects typically call for ASTM A106B or API 5L grades. Selecting the correct steel grade — whether 20# for general service, 15CrMo for elevated-temperature boiler use, or 40Cr for high-strength mechanical parts — determines whether the batch clears customs or fails third-party inspection [NEED_CITE: EN 10216 seamless steel tubes for pressure purposes]. We provide CE certification under EN 10210/10219, ISO 9001:2015 quality management, and Singapore FPC for regulated markets. Every heat number is traceable from raw billet to finished pipe, and SGS or BV inspection can be arranged before container sealing.
Steel Grade Selection and Cold-Rolled Seamless Process Explained
Carbon steel grades 10# through 45# offer increasing tensile strength for structural and machined applications, while 16Mn and 15CrMo add manganese and chromium-molybdenum for improved hardenability and high-temperature performance. International equivalents — ASTM A106B for high-temperature service, A53 for general piping, API 5L for line pipe — map closely to GB grades but require explicit chemical confirmation on the mill test certificate. The cold-rolled seamless process produces tighter dimensional accuracy and a smoother surface finish compared to hot-rolled seamless, making it suitable for hydraulic cylinders and precision machinery parts where honing or grinding follows. Slightly oiled surface treatment protects the cold-rolled finish during ocean transit without interfering with downstream machining or coating.
The Hidden Cost of Accepting Substandard Mill Test Documentation
Ordering seamless pipes without verified chemical composition and mechanical test data may save a few dollars per ton at purchase but exposes the project to weld rejection, pressure test failure, and customs detention. A mill test certificate that lists only “equivalent grade” without actual heat analysis values will not satisfy EN 10204 3.1 or 3.2 requirements [NEED_CITE: EN 10204 inspection document types for steel products]. Negative tolerance abuse — where actual wall thickness falls below the ordered nominal — reduces pressure rating and triggers rejection during hydrostatic testing. The cost of replacing a batch of seamless round steel pipe after it has reached the job site dwarfs any initial price difference.
Why Project Buyers Source Seamless Round Steel Pipe From Our Mill
We operate three dedicated production lines covering over 2,800 specifications, meaning your non-standard OD or heavy-wall request does not require brokering through a trading company that adds margin without adding value. Our in-house physical and chemical laboratory tests every heat for composition, tensile strength, and dimensional accuracy before release — the mill test certificate you receive reflects actual test data, not catalog specifications. Forty-one invention patents back our manufacturing capability, including proprietary processes for tight-tolerance cold-rolled seamless tubes. Full international certifications — ISO 9001:2015, Lloyd’s CE, Singapore FPC, and SGS/BV verification — ensure your shipment clears customs in regulated markets. We handle custom cutting, beveling, and threading to your drawing specifications, reducing secondary fabrication at your site. Professional container loading with anti-damage measures prevents the surface scratching and bending that I learned the hard way costs far more than the pipe itself.
Documentation & Compliance
- Mill test certificate documenting actual chemical composition and mechanical properties for each heat number per ASTM A106B or API 5L requirements
- CE certificate confirming compliance with EN 10210/10219 for structural hollow sections destined for European markets
- ISO 9001:2015 quality management system certificate covering the full production process from billet inspection to final dimensional check
- SGS or BV third-party inspection report available for pre-shipment verification of dimensions, surface quality, and test certificates
- Full material traceability by heat number from raw material receipt through cold-rolling, testing, and dispatch
- Export customs documentation including packing list, bill of lading, and certificate of origin for import clearance
Packaging, Loading & Delivery
- Seamless round pipes bundled with steel strips and edge protectors, sized to match container dimensions for OD 21.3–1420 mm ranges
- Slightly oiled surface preserved by waterproof paper wrapping and plastic caps on pipe ends to prevent corrosion during ocean transit
- Professional container loading plan optimized for 6 m and 12 m lengths, with wooden separators preventing tube-to-tube contact and surface damage
- Custom cutting to required lengths available before packing, reducing on-site waste and handling for boiler tube and hydraulic cylinder applications
- Heat number and steel grade marked on each pipe end with stenciled identification for traceability at destination
- FOB, CIF, and DDP shipping terms available with full tracking from Jinan port to final project site across 50+ countries
Starting Your Seamless Round Steel Pipe Inquiry
Submit your required outer diameter, wall thickness, steel grade, quantity, and destination port — we respond within 12 hours with a detailed quotation including unit price, lead time, and shipping terms. Non-standard sizes and custom lengths are accepted with low minimum order quantities. Mill test certificates and third-party inspection arrangements are confirmed before production begins.
Request Your Seamless Round Steel Pipe Quotation
Send your specifications and destination to receive pricing, mill test certificate samples, and container loading plans.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do GB steel grades like 20# and 45# compare to ASTM A106B and API 5L?
A: GB 20# closely matches ASTM A106B in carbon content and is suitable for high-temperature seamless pipe service. GB 45# offers higher carbon for increased strength in mechanical applications. API 5L grades such as B and X42 are specified for oil and gas transmission pipelines. We provide chemical composition mapping on the mill test certificate to confirm equivalence for your project specification.
Q: Can you arrange third-party inspection before shipment?
A: Yes. SGS and BV inspection services are available for pre-shipment verification of dimensions, wall thickness, surface quality, and mechanical test results. The inspection report is issued independently and accompanies the mill test certificate for customs and project documentation.
Q: What is the minimum order quantity for non-standard sizes?
A: The minimum order quantity is 1 Ton. Custom outer diameters, wall thicknesses, and lengths outside standard ranges are accepted. Cold-rolled seamless production allows tight tolerance control even for small-batch orders.
Q: What surface treatment options are available for corrosion protection?
A: Standard delivery is slightly oiled for transit protection of the cold-rolled surface. Black finish, hot-dip galvanized coating, and 3PE anti-corrosion coating are available based on your application environment and project specifications.
Q: How do you ensure pipes arrive without surface damage or bending?
A: Each Seamless Round Steel Pipe is packed with waterproof paper, plastic end caps, and wooden separators inside the container. Professional loading plans prevent tube movement during ocean transit. This protects the oiled cold-rolled surface and maintains dimensional accuracy for precision applications.
