Description
Factory-direct ZAM coated tubes — in-house ZAM coating lines with AZ61–AZ80 grade and zero spangle finish verified by SGS testing before shipment.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195/Q235/Q355 Galvanized ZAM Coated Square & Round Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube / Round Steel Pipe (ZAM Coated) |
| Steel Grade | Q195, Q235, Q355, S235JR, S275JR, S355JR, S355J2, SS400, A36 |
| Standard | ASTM, JIS, GB, EN, AISI, DIN |
| Section Shape | Square / Rectangular / Round / Flat Oval / Groove |
| Size Range | Flat oval/groove: 20×60mm – 40×75mm; Round OD: 20mm–500mm; Square/Rectangular: 20mm–500mm |
| Wall Thickness | 0.5mm–30mm (ZAM coated: 0.5mm–1.0mm; general range up to 30mm) |
| Length | 5.8m / 6m / 6.4m / 12m (5800mm–12000mm) |
| Technique | ERW (Electric Resistance Welded) / Hot Rolled / Cold Rolled |
| Surface Treatment | ZAM Coating (Zinc-Aluminum-Magnesium) / Hot Dip Galvanized (Zinc coating 30g–275g) |
| Aluminium Content | 55% |
| Coating Grade | AZ61–AZ80 |
| Spangle Type | Zero Spangle |
| Ends | With or without end caps |
| Processing Service | Welding, Punching, Cutting, Bending |
| Application | Steel structures / Construction frames / Architectural facades / Curtain walls / Machinery frames / Scaffolding / Furniture / Greenhouse structures |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Architectural Facade & Curtain Wall | Structural framing for glass curtain walls, exterior cladding supports, visible facade elements requiring zero spangle finish |
| Construction & Steel Structure | Building frames, column bracing, roof trusses in coastal or high-humidity zones |
| Machinery Manufacturing | Equipment frames, conveyor structures, precision machine bases requiring superior surface quality |
| Agricultural & Greenhouse | Greenhouse skeleton structures, irrigation support frames exposed to fertilizer corrosion |
| Scaffolding & Temporary Works | Scaffolding tubes, formwork supports where repeated assembly demands coating durability |
Where ZAM Coating Thickness Decides Whether a Coastal Facade Survives Five Years
Standard galvanized coatings corrode through in aggressive salt-air environments — ZAM delivers 3–5× longer service life through self-healing zinc-aluminum-magnesium chemistry.
I once inspected a batch of galvanized oval tubes bound for a Melbourne curtain wall project. The client’s on-site thickness gauge read 38 microns against a contracted 60-micron minimum. The entire container sat at port awaiting rework, and the stripping and re-coating cost nearly doubled the original material spend. That kind of failure does not come from bad intent — it comes from mills cutting coating weight to save zinc cost, then shipping without third-party verification. [NEED_CITE: zinc-aluminum-magnesium coating corrosion resistance mechanism and comparison to pure zinc]
For buyers sourcing a ZAM coated galvanized square steel tube supplier, the real risk is not finding a vendor. It is receiving tubes with inconsistent coating adhesion, uneven zinc-aluminum-magnesium distribution, or missing EN 10219 dimensional certificates that block EU customs clearance. [NEED_CITE: EN 10219 cold-formed structural hollow section dimensional tolerance requirements]
How ZAM Coated Profiles Match Architectural and Structural Demands
A ZAM coated galvanized square steel tube supplier serving facade contractors must deliver profiles that combine corrosion resistance with visual consistency. The zero spangle finish on AZ61–AZ80 grade ZAM coating eliminates the uneven crystalline patterns typical of standard hot dip galvanizing, making these tubes suitable for exposed architectural framing where appearance matters. Flat oval and groove sections in the 20×60mm to 40×75mm range fill specification gaps that most mills cannot cover, allowing curtain wall engineers to specify non-standard profiles without splitting orders across multiple vendors. Wall thickness from 0.5mm to 1.0mm for ZAM-coated tubes addresses light structural and decorative applications, while the broader 0.5mm–30mm range covers heavy structural frames.
Engineering Compliance and Certification Requirements
Structural hollow sections used in load-bearing frames must conform to dimensional and mechanical requirements under EN 10219 for cold-formed welded sections or EN 10210 for hot-finished profiles. [NEED_CITE: EN 10219 and EN 10210 structural hollow section compliance for EU market] Steel grade equivalence across GB, EN, and ASTM systems — such as Q355 matching S355JR or ASTM A500 Gr.C — requires proper documentation to avoid material substitution disputes during project inspection. ZAM coating, with its 55% aluminium content and magnesium addition, forms a dense protective layer that resists white rust formation better than conventional zinc galvanizing, making it the preferred choice for coastal construction and greenhouse structures exposed to ammonia-based fertilizers. Third-party inspection by SGS or BV before shipment provides the mill test certificate and coating thickness report that EU importers need for CE marking compliance.
Steel Grade Selection and ZAM Coating Process Explained
The Q195–Q355 grade series follows the Chinese GB standard system, where the number indicates minimum yield strength in MPa. Q195 suits light-duty furniture and greenhouse frames; Q235 covers general construction and scaffolding; Q355 serves structural applications requiring higher load capacity. These grades correspond to S235JR, S275JR, and S355JR/S355J2 under EN standards, and roughly align with ASTM A36 and A500 Gr.B/C respectively. [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series standards]
ERW (Electric Resistance Welded) processing forms square and rectangular tubes from coil through continuous forming and high-frequency welding, offering tight dimensional tolerance and cost efficiency for structural sizes from 20mm to 500mm. Cold rolled feedstock delivers smoother surface finish, which matters when ZAM coating must bond uniformly without substrate irregularities.
The ZAM coating process applies a zinc-aluminum-magnesium alloy layer with 55% aluminium content at AZ61–AZ80 coating grade. Magnesium in the alloy promotes formation of a dense, stable corrosion product layer — primarily zinc hydroxychloride and simonkolleite — that self-heals minor scratches and cut edges. This mechanism gives ZAM-coated tubes significantly longer corrosion resistance than conventional hot dip galvanized coatings of equivalent thickness, particularly in chloride-rich or industrial atmospheres.
Hidden Costs of Procuring Coating and Grade Non-Conformance
Ordering ZAM coated galvanized square steel tubes without verified coating thickness and proper mill test certificates creates compounding downstream costs. Coating below specification fails inspection at the project site, triggering rejection or costly rework — as demonstrated by the Melbourne port incident where under-gauged galvanizing forced full reprocessing. [NEED_CITE: consequences of non-conforming galvanized coating thickness in construction projects] Missing or incorrect CE documentation under EN 10219 delays customs clearance in EU markets, incurring port storage fees and project schedule penalties. Negative tolerance stacking on wall thickness reduces actual load capacity below design assumptions, creating structural safety concerns that only surface during load testing or — worse — during service. Material traceability gaps prevent proper heat number verification, blocking acceptance by project engineers or third-party inspectors.
Procurement Advantages of Direct Factory Supply
As the original inventor of sharp-corner rectangular steel tubes in China with 41 invention patents, our factory operates three dedicated production lines covering 2,800+ specifications with wall thickness up to 40mm. In-house physical and chemical laboratories perform dimensional, mechanical, and chemical testing on every production batch, with full inspection reports and photographs provided before shipment. We hold ISO 9001:2015, Lloyd’s CE certification under EN 10219/EN 10210, Singapore FPC, and SGS/BV verification — ensuring documentation compliance for EU, North American, and regulated-market imports. Custom non-standard sizes, cutting, marking, and professional container loading are handled in-house, eliminating coordination gaps between multiple suppliers. Our ZAM coated galvanized square steel tube supply includes flat oval and groove profiles that most mills do not offer, allowing facade and curtain wall contractors to consolidate orders for standard and specialty sections in a single shipment to 50+ countries.
Documentation & Compliance
- Mill test certificate documenting Q195/Q235/Q355 chemical composition and mechanical properties per GB/T 13793 or EN 10219 as specified
- CE certificate under EN 10219 for cold-formed welded structural hollow sections, required for EU market customs clearance
- ISO 9001:2015 quality management system certificate covering ZAM coating process and dimensional inspection
- SGS or BV third-party inspection report verifying ZAM coating thickness (AZ61–AZ80 grade), aluminium content, and adhesion test results
- Material traceability by heat number stamped on each tube, linking back to coil certification and coating batch records
- Full customs documentation set: commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- ZAM coated tubes bundled with steel strips and edge protectors to prevent zinc-aluminum-magnesium coating abrasion during ocean transit
- Zero spangle surface protected by interleaving paper or plastic wraps on flat oval and groove sections (20×60mm to 40×75mm) to avoid contact marking
- Container loading optimized for 5.8m/6m/12m lengths with anti-roll cradles and timber separators, maximizing payload for 20ft and 40ft shipments
- Custom cutting to project-specified lengths within 5800mm–12000mm range, with cut ends sealed to prevent edge corrosion before delivery
- Heat number and steel grade (Q195/Q235/Q355) marked on each tube at 1-meter intervals for site traceability
- FOB, CIF, and DDP shipping terms available with professional tube loading supervision and tracking until port arrival
Submit Specifications for ZAM Tube Quotation and Mill Test Review
Provide your required section shape, dimensions, steel grade, ZAM coating grade, quantity, and destination port to receive a detailed quotation with unit pricing, production lead time, and shipping terms. We will supply product samples, mill test certificates, and arrange SGS/BV third-party inspection upon request to confirm coating thickness and dimensional compliance before contract signing.
Request ZAM Coated Tube Quotation with Full Certification Package
Send your specification sheet — including section profile, size range, steel grade, coating requirement, and target quantity — to receive pricing, mill test certificate samples, and third-party inspection arrangement within 12 hours.
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: What is ZAM coating and how does it compare to standard hot dip galvanizing?
A: ZAM coating is a zinc-aluminum-magnesium alloy layer with 55% aluminium content applied at AZ61–AZ80 grade. The magnesium addition promotes formation of a dense, self-healing corrosion product that provides 3–5× longer corrosion resistance than conventional hot dip galvanized zinc coatings of equivalent thickness, particularly in chloride-rich coastal and industrial environments.
Q: Can you produce non-standard profiles like flat oval or groove tubes with ZAM coating?
A: Yes. We produce flat oval and groove sections in the 20×60mm to 40×75mm range with ZAM coating at 0.5mm–1.0mm wall thickness, alongside standard square, rectangular, and round profiles. These non-standard shapes fill specification gaps for architectural facade and curtain wall applications.
Q: What certifications do you provide for EU market compliance?
A: We supply CE certification under EN 10219 (cold-formed welded structural hollow sections) and EN 10210 (hot-finished structural hollow sections), issued by Lloyd’s Register. Full documentation includes mill test certificates, ISO 9001:2015 quality certificate, and SGS/BV third-party inspection reports for coating thickness and dimensional verification.
Q: How do you ensure ZAM coating thickness uniformity across the tube surface?
A: Our in-house laboratory performs coating thickness testing using magnetic induction gauges at multiple points along each tube — top, bottom, and both sides — to verify AZ61–AZ80 grade compliance. Third-party inspection by SGS or BV is available before shipment to independently confirm coating weight, aluminium content, and adhesion performance.
Q: What is the zero spangle finish and why does it matter for architectural applications?
A: Zero spangle refers to a smooth, uniform ZAM coating surface without the visible crystalline zinc flower patterns typical of standard galvanized finishes. This provides consistent visual appearance for exposed architectural framing, glass curtain wall supports, and facade elements where coating aesthetics affect project acceptance.
