Description
Factory-direct Q235B ERW supply — In-house physical and chemical lab verifies every 6 m pipe before dispatch.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B ERW Round Steel Pipe |
| Product Type | ERW Welded Round Steel Pipe |
| Steel Grade | Q235B, Q195–Q345 |
| Standard | GB / ASTM |
| Section Shape | Round |
| Technique | ERW (Electric Resistance Welding) / Longitudinal Seam |
| Surface Treatment | Hot Rolled / Black (Non-oiled) |
| Length | 6 m |
| Tolerance | ±1% |
| Invoicing | By Actual Weight |
| Application | Construction Structure / Structural frames / Building frameworks |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction Companies | Building frames, column supports, roof trusses for commercial and industrial structures |
| Steel Structure Fabricators | Raw material for welded portal frames, mezzanine floors, and bracing systems |
| Machinery Manufacturers | Equipment bases, conveyor supports, and machine guarding frames |
| Infrastructure Contractors | Bridge handrails, sound barrier posts, and utility pole foundations |
Where Negative Tolerance Fails a Structural Frame Inspection
A 6 m Q235B ERW round pipe that passes visual check can still fail caliper verification at the weld seam.
On a recent project, a batch of Q235B ERW round steel pipe arrived at site with the weld zone wall thickness dipping below the lower limit — the whole lot was rejected by the site supervisor after third-party re-inspection. The root cause was aggressive negative tolerance eating into the minimum guaranteed thickness right where the ERW longitudinal seam runs. For a Q235B ERW round steel pipe supplier running in-house lab checks, this means caliper verification at the weld, not just at the body. [NEED_CITE: EN 10219 dimensional tolerance requirements for welded hollow sections]
Matching 6 m Hot Rolled Black Pipe to Structural Frameworks
The 6 m standard length of this Q235B ERW round steel pipe aligns with typical column and beam spans in low- to mid-rise steel frames, reducing on-site cutting waste. Hot rolled black (non-oiled) surface accepts primer and paint systems directly, which matters when the pipe will be welded into bracing or truss nodes — oil-coated finishes cause weld porosity. With ±1% tolerance and actual-weight invoicing, project estimators get predictable tonnage without paying for excess wall.
Engineering Compliance and Grade Selection for Q235B Structures
Q235B sits in the Chinese GB system as a mild carbon structural steel, broadly comparable to S235JR in EN 10219 and A36 in ASTM A36 for non-critical structural members. For projects governed by EN 1993 (Eurocode 3) or AISC 360, the engineer must confirm grade equivalence through the mill test certificate — a Q235B ERW round steel pipe shipped with only a commercial invoice will not clear EU customs or pass AISC-compliant fabrication audits. [NEED_CITE: steel grade equivalence between GB Q235B and EN S235JR / ASTM A36] The hot rolled black condition also means the pipe can be shot-blasted and coated on site without stripping factory-applied oils, which saves time on large-frame projects.
Understanding Q235B Grade and ERW Longitudinal Seam Process
Q235B is a non-alloy carbon structural steel where the “235” denotes the nominal yield point in MPa, suitable for general construction frames, scaffolding, and non-pressurized structural members. The ERW (Electric Resistance Welding) longitudinal seam process forms the pipe by rolling a hot-rolled coil into a cylinder and fusing the seam through electrical resistance heat — no filler metal, which keeps the weld zone narrow and consistent. Compared to seamless pipe, ERW offers lower cost for non-high-pressure applications; compared to SSAW, the straight longitudinal seam is easier to inspect ultrasonically along the full length. The hot rolled black finish, left non-oiled, is the standard delivery condition for pipes that will be welded and painted in fabrication shops.
Hidden Costs of Sourcing Unverified ERW Round Pipe
Ordering a Q235B ERW round steel pipe without verified mill test certificates risks three failure modes: customs rejection in regulated markets (EU, GCC, Singapore) where CE or SASO marking is mandatory; structural non-conformance when the actual yield strength falls below the Q235B nominal value; and weld seam defects that only surface during fabrication, causing rework and schedule delays. [NEED_CITE: EN 10219 cold-formed welded structural hollow section certification requirements] A pipe that looks right on the outside but carries inconsistent wall thickness at the seam becomes a liability the moment the fabricator cuts, bevels, or loads it.
Why Project Buyers Source Q235B ERW Pipe from Shandong Xin Jiyuan
Every Q235B ERW round steel pipe leaving our Jinan facility passes through an in-house physical and chemical laboratory — dimensional checks with calibrated calipers, chemical composition verification, and mechanical testing per GB standards. We hold ISO 9001:2015, Lloyd’s CE certification under EN 10210/EN 10219, and Singapore FPC, so the same batch can serve EU, Middle East, and Southeast Asian projects without re-certification. With over 2,800 specifications across our tube and section steel lines, non-standard diameters or lengths for Q235B ERW round pipe can be produced alongside standard 6 m stock, avoiding the need to split orders across multiple mills. Professional container loading with anti-damage measures ensures the hot rolled black surface arrives without dents or seam distortion — a detail that matters when the pipe goes straight into fabrication without re-conditioning.
Documentation & Compliance
- Mill test certificate documenting Q235B chemical composition (C, Mn, Si, S, P) and mechanical properties per GB/T 700, issued per heat number
- CE certificate under EN 10219 for cold-formed welded structural hollow sections, required for EU market customs clearance
- ISO 9001:2015 quality management certificate covering the full ERW production and inspection process
- SGS or BV third-party inspection report available upon request, covering dimensional, visual, and mechanical checks
- Material traceability by heat number stamped on each pipe, matching the mill test certificate
- Full export documentation set: packing list, bill of lading, certificate of origin, and commercial invoice
Packaging, Loading & Delivery
- 6 m Q235B ERW round pipes bundled with steel strips and edge protectors, preserving the hot rolled black surface during ocean transit
- Non-oiled black finish requires no special coating protection but benefits from covered container loading to avoid rain staining
- Bundle weight optimized for 20 ft and 40 ft containers, maximizing payload for round sections up to mid-range diameters
- Heat number and Q235B grade stenciled on each pipe end for on-site identification and traceability
- FOB Jinan/Qingdao, CIF, or DDP terms available, with professional tube loading plans to prevent shifting and bending
- Custom cutting to non-standard lengths available at the mill before shipment, reducing on-site waste for frame fabricators
Requesting a Quote for Q235B ERW Round Pipe
Submit the outer diameter, wall thickness, total tonnage, and destination port to receive a detailed quotation including unit price, production lead time, and shipping terms. Mill test certificates and third-party inspection options (SGS/BV) are confirmed at the quotation stage, so project compliance requirements are addressed before the deposit is paid.
Frequently Asked Questions
Q: What is the difference between Q235B and equivalent ASTM or EN grades?
A: Q235B is a Chinese GB standard non-alloy structural steel with a nominal yield point of 235 MPa. It is broadly comparable to S235JR under EN 10219 and A36 under ASTM A36 for general structural applications, but exact equivalence depends on the project specification and must be confirmed through the mill test certificate.
Q: Can you provide third-party inspection before shipment?
A: Yes, SGS or BV third-party inspection can be arranged at our facility before shipment, covering dimensional checks, visual weld inspection, and mechanical testing. The inspection scope and cost are confirmed at the quotation stage.
Q: What is the MOQ for custom lengths or non-standard diameters?
A: The standard MOQ is 1 Ton. Custom lengths and non-standard diameters for Q235B ERW round pipe can be produced to order, with typical production lead times confirmed after the drawing or specification is reviewed.
Q: Do you offer galvanized or painted surface treatment options?
A: The standard delivery condition is hot rolled black (non-oiled). Hot-dip galvanized or painted finishes can be arranged as a secondary processing step, with the additional cost and lead time quoted separately.
Q: How do you ensure weld quality for ERW longitudinal seam pipes?
A: Every Q235B ERW round steel pipe undergoes in-house dimensional and mechanical testing in our physical and chemical laboratory. Wall thickness is verified with calibrated calipers at the weld seam and body, and chemical composition is checked per heat number against the GB/T 700 standard.
Get Your Q235B ERW Round Pipe Quote with Mill Test Certificate
Send your diameter, wall thickness, quantity, and destination port to receive a full quotation and sample mill test certificate within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
