Description
Factory-Direct Seamless Pipe Supply — Q235 and Q345 grades in OD 21.3–1420 mm ship directly from Jinan production lines with original mill certificates attached to every heat.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 / Q345 Seamless Round Steel Pipe |
| Product Type | Seamless Round Steel Pipe |
| Steel Grade | 10#, 20#, 35#, 45#, Q195, Q215, Q235, Q345, Q345A, Q345C, 16Mn, 40Cr, 15CrMo, 45Mn2 |
| Standard | API, ASTM (A53, A106), BS, DIN, GB, JIS |
| Section Shape | Round |
| Size Range | OD 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 |
| Tolerance | ±1% |
| Ends | Plain / Beveled (as required) |
| Application | Fluid transport, boiler, oil & gas pipeline, chemical fertilizer pipeline, drill pipe, hydraulic pipe, structural engineering, machinery parts, automobile & tractor stress components |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Oil & Gas / Petrochemical | High-pressure transmission pipelines, drill pipe, chemical fertilizer feed lines |
| Power Generation | High-temperature boiler tubes, superheater systems, heat exchanger circuits |
| Heavy Machinery | Hydraulic cylinder barrels, press frames, crane boom sections |
| Structural Engineering | Load-bearing columns, truss members, bridge bearing piles |
| Automotive & Tractor | Drive shafts, axle housings, stress-bearing chassis components |
Where Steel Grade Equivalence Decides Whether Your Shipment Clears Customs
A container held at the port because Q345 on the packing list does not appear in the ASTM table costs more in demurrage than the pipe itself.
Project spec sheets written in European or American standards routinely list S355, A106 Grade B, or API 5L X42 — none of which appear verbatim on a Chinese mill certificate. Buyers who discover this mismatch only at the destination port face weeks of re-documentation, third-party re-certification fees, or outright rejection by the site engineer [NEED_CITE: steel grade equivalence between EN and ASTM standards]. I have watched entire batches of cold-rolled seamless pipe sit in Jebel Ali bonded storage because the importer could not prove that the supplied grade met the mechanical requirements the consultant specified. The gap is not technical — the chemistry and tensile properties often align — it is documentary. A supplier who understands cross-standard mapping and issues a clear equivalence statement at the quotation stage eliminates this risk before the first ton is produced.
Matching Q235 and Q345 Grades to Pressure and Structural Demands
Q235 serves general structural and low-pressure fluid conveyance where formability and weldability matter more than tensile ceiling. Q345 (and its variants Q345A, Q345C) steps into medium-to-high pressure pipelines and load-bearing frames, with 16Mn and 15CrMo covering elevated-temperature boiler and petrochemical service. The cold-rolled seamless process produces a tighter outer-diameter tolerance and a smoother internal surface than hot-finished alternatives — critical when the Seamless Round Steel Pipe will become a hydraulic cylinder barrel or a boiler tube where flow turbulence or fatigue cycling is a concern. Every heat is traced from slab to finished length, and the mill test certificate travels with the shipment.
Engineering Code Compliance and Surface Condition
Structural designers working to EN 1993 or AISC 360 require documented yield strength and verified dimensional tolerance before they sign off on a material submittal. The ±1% tolerance on OD and wall thickness keeps these pipes within the acceptance bands of most international codes, while the slightly oiled surface protects against transit corrosion without interfering with downstream welding, 3PE coating, or galvanizing [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]. For projects in sour-service or marine environments, the base pipe can be upgraded with external coating at the buyer’s direction — the oiled condition simply preserves the bare steel until that step. Beveled or plain ends are supplied per the connection method specified: beveled for butt-weld pipeline joints, plain for coupler or flange assemblies.
Why the Cold-Rolled Seamless Process Matters for This Size Range
Seamless pipe in the OD 21.3–1420 mm range can be produced by hot-rolling or cold-rolling; the cold-rolled route delivers superior surface finish and tighter dimensional control, which is why boiler and hydraulic applications specify it. Hot-rolled seamless is typically chosen for heavy-wall, large-diameter pipeline where absolute surface perfection is secondary to throughput. Within the Q-series grading system, Q235 maps broadly to S235JR in EN terms and offers reliable weldability for structural frames; Q345 aligns with S355 in yield class and is the workhorse for pressure-containing applications. Alloy additions such as 40Cr, 15CrMo, and 45Mn2 extend the range into quenched-and-tempered territory for machined parts and high-temperature service. The ±1% tolerance means the theoretical weight calculation stays close to actual weight, reducing billing disputes at delivery [NEED_CITE: seamless steel pipe manufacturing process comparison hot-rolled vs cold-rolled].
The Hidden Cost of Ordering the Wrong Grade or Missing Paperwork
Specifying Q235 when the structural engineer required Q345 does not show up until the first weld fails a bend test or the column deflects beyond limit state — at which point the entire batch is scrap. Missing or incomplete mill certificates trigger customs holds in the EU and GCC, where importers must present EN-compliant documentation before the container leaves the port. Negative tolerance beyond the declared ±1% range reduces actual wall thickness, compromising pressure rating and voiding the designer’s safety factor. These failures are never the pipe’s fault; they are procurement failures — the result of ordering from a supplier who treats grade equivalence as an afterthought rather than a core competency [NEED_CITE: ASTM A106 grade B chemical composition and mechanical requirements].
Why Global Buyers Source This Seamless Round Steel Pipe From Xin Jiyuan
Every Seamless Round Steel Pipe in this range ships with an original mill test certificate showing heat-level chemistry and mechanical results — not a template document generated in the sales office. Our in-house lab runs three-stage inspection on each production lot, and SGS or BV third-party inspection is arranged on request before the container is sealed. The Jinan facility holds ISO 9001:2015 certification and Lloyd’s CE marking under EN 10210/EN 10219, which satisfies the documentary requirements for European and Middle Eastern project tenders. With over 2,800 specifications in ready stock — spanning OD from 21.3 mm to 1420 mm and wall thickness up to 300 mm — standard items dispatch within days, while custom non-standard sizes and lengths are produced within typical lead times of 15–25 days. Factory-direct pricing means volume buyers and long-term partners receive tiered discounts without intermediary markup, and our export team handles container loading optimization to minimize freight cost per ton.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition, yield strength, and tensile properties per GB, ASTM A53, or A106 as specified
- CE certificate under EN 10210/EN 10219 for shipments entering the European Economic Area
- ISO 9001:2015 quality management system certificate covering the full production and inspection process
- SGS or BV third-party inspection report available upon request, conducted before container sealing
- Full material traceability by heat number from slab to finished pipe length
- Export documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Slightly oiled seamless pipes bundled with steel strips and edge protectors to preserve surface condition during ocean transit
- 6 m, 6.4 m, and 12 m lengths loaded into 20 ft or 40 ft containers with optimized stowage plans to maximize payload per shipment
- Heat number and steel grade stenciled on each pipe end for site identification and traceability verification
- Plain or beveled ends capped with plastic protectors to prevent damage and contamination during handling
- FOB, CIF, and DDP terms available with door-to-door logistics coordination to project site or warehouse
- Split shipments and consolidated multi-product container loading supported for buyers sourcing pipes, plates, and sections together
Getting a Firm Quote for Your Seamless Round Steel Pipe Requirement
Send the specification sheet — OD, wall thickness, length, steel grade, standard, and destination port — and receive a detailed quotation with volume-based pricing, production lead time, and available mill test certificate format within 12 hours. For non-standard dimensions or alloy grades such as 15CrMo or 40Cr, the engineering team confirms feasibility and custom tooling requirements before the contract is signed.
Frequently Asked Questions
Q: How do Chinese steel grades Q235 and Q345 map to ASTM and EN equivalents?
A: Q235 broadly corresponds to S235JR in EN and A283 Grade C in ASTM for structural use; Q345 aligns with S355JR/J0 in EN and A572 Grade 50 in ASTM for higher-strength structural and pressure applications. Exact equivalence depends on the specific sub-grade (Q345A vs Q345C) and the required impact testing temperature. We provide a detailed cross-reference table with each quotation.
Q: What certificates are provided, and can third-party inspection be arranged before shipment?
A: Every batch ships with an original mill test certificate showing heat-level chemical composition and mechanical properties. ISO 9001:2015 and Lloyd’s CE (EN 10210/EN 10219) certificates are available for project compliance. SGS or BV third-party inspection can be arranged at the buyer’s request before container loading.
Q: What is the minimum order quantity for custom non-standard sizes?
A: The MOQ for standard specifications is 1 ton. For custom OD, wall thickness, or length outside the standard range, the minimum depends on the production run setup; typical custom orders are fulfilled within 15–25 days from contract signing and deposit receipt.
Q: How is billing calculated — theoretical weight or actual weight?
A: Billing can be arranged by theoretical weight (based on standard density and nominal dimensions with ±1% tolerance) or by actual weighbridge weight at the buyer’s option. The quotation specifies the billing method before the contract is signed to avoid disputes at delivery.
Q: What surface treatment options are available beyond the standard slightly oiled condition?
A: The standard delivery condition is slightly oiled to prevent transit corrosion. For specific applications, the base seamless pipe can be supplied for downstream processing including galvanizing, 3PE coating, or painting — these are arranged per the buyer’s specification and quoted separately.
Request Your Seamless Round Steel Pipe Quotation Today
Submit your specification — OD, wall thickness, grade, standard, and destination — to receive factory-direct pricing and mill test certificate confirmation within 12 hours.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
