Description
Factory-Direct Supply, Zero Broker Markup — Gr.B galvanized ERW pipes roll from our own mill and hot-dip line, so every heat number traces back to one source.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Gr.B Galvanized ERW Round Steel Pipe |
| Product Type | Galvanized ERW Round Steel Pipe |
| Steel Grade | Gr.B |
| Standard | BS 1387, API |
| Section Shape | Round |
| Size Range | 21.3 – 660 mm (1/2″ – 8″ / DN15 – DN200) |
| Wall Thickness | 1.8 – 8 mm (up to 20 mm per general spec) |
| Length | 5.8 m / 6 m / 6.4 m / 12 m |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Dip Galvanized (Zinc Coated Min 300g/m²) |
| Tolerance | ±5% / ±10% / ±15% (varies by dimension) |
| Ends | Threaded with couplings (NPT/BS) |
| Application | Fluid transport / Gas conveyance / Structure pipe / Construction / Boiler / Oil & Chemical pipeline |
| Invoicing | By Theoretical Weight |
| Surface Condition | Non-oiled |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & Industrial Plant | Process water lines, cooling water circuits, fire protection risers in refinery and chemical complexes |
| Commercial Construction | Structural support columns, scaffolding uprights, handrail posts in warehouse and logistics centers |
| Infrastructure | Drainage culverts, cable protection conduits, street lighting masts along highway projects |
| Oil & Gas Conveyance | Low-pressure gas distribution lines, fuel oil transfer piping in tank farms |
| Boiler & HVAC | Steam condensate return lines, chilled water circulation loops in district energy plants |
Where Zinc Coating Weight Decides Whether a DN15 PN10 Galvanized Steel Pipe Supplier Ships or Re-Galvanizes
A 300g/m² hot-dip coat is the line between a pipe that survives ten years in a Gulf coastal site and one that fails a third-party thickness test at the port.
I watched a full container of DN15 PN10 galvanized pipes get rejected in Riyadh because the zinc layer measured barely 35 microns instead of the 70 specified. The re-galvanizing bill wiped out the entire order margin, and the project schedule slipped three weeks. Buyers sourcing from a DN15 PN10 galvanized steel pipe supplier often discover this gap only when the material reaches the job site — too late for claims, too expensive for rework. [NEED_CITE: hot dip galvanizing coating thickness standards for BS 1387 pipes]
The root cause is fragmented sourcing: the trader buys black ERW pipe from one mill, outsources galvanizing to a cheapest-bidder dip shop, and stamps a generic mill cert on the bundle. No heat-number traceability, no coating-weight test report, no accountability when the zinc peels after one monsoon season.
How Gr.B Hot-Dip Galvanized ERW Pipe Matches Field Assembly Demands
Threaded ends with NPT or BS couplings let site crews assemble fluid and gas lines without welding permits — critical on live-plant tie-ins and confined-space scaffolding jobs. The hot-dip zinc coat at ≥300g/m² covers both external and internal surfaces, protecting the bore against condensation corrosion in humid coastal projects across the Middle East and Southeast Asia. As a DN15 PN10 galvanized steel pipe supplier operating our own dip line, we control immersion time and bath temperature to hit the coating weight spec consistently across the full DN15–DN200 range.
Engineering Compliance Across BS 1387 and API Frameworks
BS 1387 governs the threaded-end geometry and coupling engagement length, while API references guide pressure-rating expectations for gas conveyance. For EU-bound shipments, EN 1090 structural fabrication standards may apply when the pipe serves as a structural member rather than pure fluid conveyance. [NEED_CITE: BS 1387 threaded pipe end dimensional requirements] Specifying the correct thread standard — NPT for North American projects, BS for Commonwealth markets — avoids costly re-threading on site. Our engineering team reviews shop drawings before production to confirm thread form, coupling class, and length match the project spec.
Gr.B Steel Grade and ERW Process Explained
Gr.B under BS 1387 is a mild-steel grade suited to low- and medium-pressure fluid transport, offering adequate formability for threading and bending without cracking the zinc coat. The ERW (Electric Resistance Welded) process forms the round section by passing a continuous steel strip through forming rolls and welding the seam with high-frequency current — producing a consistent wall thickness and a smooth internal bore that minimizes flow turbulence. Hot-dip galvanizing then immerses the finished pipe in molten zinc, creating a metallurgical bond that outperforms pre-galvanized (electro-galvanized) alternatives in both coating thickness and adhesion. The non-oiled surface condition means the pipe arrives ready for site welding or threading without solvent cleaning. [NEED_CITE: ERW versus seamless pipe manufacturing process comparison]
The Hidden Cost of Buying from the Wrong DN15 PN10 Galvanized Steel Pipe Supplier
Material substitution — receiving a lower grade stamped as Gr.B — can pass visual inspection but fail tensile testing at the project lab, triggering batch rejection and schedule delays. Missing or forged mill test certificates create customs clearance holds, especially on projects requiring CE marking or third-party inspection. Negative tolerance abuse on wall thickness reduces theoretical weight invoicing accuracy and, more critically, compromises pressure rating in gas conveyance service. [NEED_CITE: material traceability requirements for structural steel pipe procurement]
Why Project Teams Source from XJY Structure
Our vertically integrated setup — own steel mill feeding directly into the fabrication workshop and hot-dip galvanizing line — eliminates the broker layer that introduces certification gaps. Every DN15 PN10 galvanized steel pipe order carries a mill test certificate traceable to a specific heat number from our own production. We stock over 2,800 specifications in raw material, so DN15 through DN200 sizes in Gr.B are pulled from inventory rather than waiting for third-party mill delivery. Our in-house NDT and dimensional inspection catch wall-thickness drift and thread-form errors before the pipe leaves Jinan. Third-party inspection by SGS, BV, or TUV is arranged on request, with reports included in the export documentation package.
Documentation & Compliance
- Mill Test Certificate documenting Gr.B chemical composition and dimensional compliance per BS 1387, with heat-number traceability to our own steel mill
- Hot-dip galvanizing inspection report confirming zinc coating weight ≥300g/m², tested by magnetic gauge method on production samples
- Third-party inspection report from SGS / BV / TUV covering dimensional checks, visual coating assessment, and thread verification before shipment
- ISO 9001 quality management certificate covering the full process from ERW pipe forming through hot-dip galvanizing and final packing
- Complete customs export documentation: commercial invoice, packing list, bill of lading, and certificate of origin for destination-country clearance
- Welding procedure records (WPS/PQR) available when Gr.B galvanized pipes are specified for structural welding applications under EN 1090 or AWS frameworks
Packaging, Loading & Delivery
- Gr.B galvanized ERW pipes bundled with steel strips and edge protectors to preserve the hot-dip zinc coating during ocean transit and crane handling
- Threaded ends fitted with plastic end caps to prevent thread damage and moisture ingress inside the pipe bore during container loading
- DN15–DN50 sizes nested inside larger diameters to maximize 20ft and 40ft container payload, reducing per-meter freight cost for mixed-size orders
- Standard lengths of 5.8 m and 6 m optimized for 20ft container internal dimension; 6.4 m and 12 m lengths shipped in 40ft open-top or flat-rack containers with lashing plans
- Each bundle tagged with heat number, steel grade Gr.B, size, and length for site identification and MTC cross-referencing
- FOB Qingdao or CIF destination port terms available; door-to-door logistics coordinated for Middle East, Southeast Asia, and African project sites
Getting a Quote for Your Gr.B Galvanized Pipe Requirement
Share your project drawing or bill of quantities specifying pipe size, wall thickness, length, thread standard, and destination port. We return a detailed quotation covering material, hot-dip galvanizing, threading, packing, and freight within 24 hours, along with the mill test certificate template and production timeline.
Request Your Gr.B Galvanized ERW Pipe Quote with Full MTC
Send your specification list and destination port to receive pricing, mill test certificate samples, and a production schedule within one business day.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: What is the difference between hot-dip galvanized and pre-galvanized Gr.B pipes?
A: Hot-dip galvanizing immerses the finished ERW pipe in molten zinc, producing a metallurgical bond with coating weight ≥300g/m² that covers both external and internal surfaces. Pre-galvanized (electro-galvanized) pipe receives a thinner zinc layer — typically 30–60g/m² — applied before forming, leaving the weld seam and cut ends partially exposed. For projects in corrosive environments such as coastal construction or chemical plants, hot-dip galvanized pipe delivers significantly longer service life.
Q: How do I specify the correct thread standard — NPT or BS — for my project?
A: NPT (National Pipe Taper) threads are standard for North American and API-referenced projects, while BS (British Standard) parallel or tapered threads apply to Commonwealth markets and BS 1387-specified orders. Confirm the thread form on your project specification or piping schedule before ordering, as re-threading galvanized pipe on site damages the zinc coating and voids corrosion protection.
Q: Can I trace the material back to the original steel mill heat?
A: Yes. Because XJY Structure operates its own steel mill, every Gr.B galvanized ERW pipe carries a heat number stamped on the bundle tag and documented on the Mill Test Certificate. This provides full chemical composition and dimensional traceability from raw steel strip through ERW forming, hot-dip galvanizing, and final shipment — closing the certification gap that occurs when brokers source black pipe and galvanizing from separate suppliers.
Q: How is theoretical weight calculated, and what tolerance applies?
A: Gr.B galvanized ERW pipes are invoiced by theoretical weight calculated from the specified outer diameter, wall thickness, and length, using the standard steel density formula. Dimensional tolerances of ±5% to ±15% apply depending on the parameter — tighter on outer diameter, wider on wall thickness — per BS 1387 and general ERW pipe standards. The zinc coating adds approximately 3–6% to the bare pipe weight, factored into the theoretical calculation.
Q: What is the typical delivery time and how are mixed-size orders packed for container shipment?
A: Standard production lead times apply once the deposit is received and shop drawings are approved. For mixed-size orders, DN15–DN50 pipes are nested inside larger diameters to maximize container payload. Standard lengths of 5.8 m and 6 m fit 20ft containers; 12 m lengths require 40ft containers. Each bundle is strapped with steel strips, fitted with edge protectors to preserve the zinc coating, and tagged with heat number and size for site identification.
