Durable Galvanized Square Steel Pipe ASTM A500, 20X20mm to 400X400mm

• Customization: Available
• Type: Welded
• Technique: ERW
• Model NO.: Q235B Q355B ASTM A500
• Material: Carbon Steel
• Surface Treatment: Hot DIP Galvanized
• Usage: Pipeline Transport, Boiler Pipe, Hydraulic/Automobile Pipe, Food/Beverage/Dairy Products, Machinery Industry, Construction & Decoration, Special Purpose
• Section Shape: Square
• Standard: ASTM, GB, JIS, En
• Grade: Q235B, Q355b, ASTM A500
• Outer Dimension: 20X20mm - 400X400mm
• Wall Thickness: 1.0mm - 12.0mm
• Length: 6m, 12m, as Customer's Request
• Zinc Coating Weight: ≥80G/M²
• Zinc Coating Thickness: ≥45μm
• Yield Strength: ≥235MPa
• Tensile Strength: Tensile Strength 370-500MPa
• Elongation: ≥26%
• Processing Service: Cutting, Drilling, Bending
• Size Tolerance: ±0.5mm
• MOQ: 5 Tons
• Delivery Time: 7-15 Days
• Certification: ISO9001, SGS, BV
• Transport Package: Packed in Bundles
• Trademark: KANGHONG
• Origin: Shandong, China
• Production Capacity: 500000 Ton

Product Description

Product Description

Galvanized Square Steel Tube / Pipe – Hot Dipped & Pre-Galvanized for Construction & Structural Applications

We are a premier manufacturer and exporter of Galvanized Square Steel Tubes (Hollow Structural Sections - HSS) in China. Our galvanized square pipes are produced using high-quality carbon steel strips or plates, formed into square hollow sections through high-frequency electric resistance welding (ERW), and subsequently treated with a protective zinc coating through either Hot-Dip Galvanizing (HDG) or Pre-Galvanizing processes.

Our products strictly comply with international standards including ASTM A500, EN 10219, JIS G3466, AS/NZS 1163, and GB/T 6728. With a comprehensive range of sizes, wall thicknesses, and zinc coating options, our galvanized square tubes are the preferred choice for construction frameworks, structural supports, fencing systems, agricultural greenhouses, solar mounting structures, and general fabrication.

Specification

Parameter	Specification
Product Name	Galvanized Square Steel Tube / Pipe
Type	Hot-Dip Galvanized (HDG) / Pre-Galvanized
Material Grade	Hot-Dip Galvanized: ASTM A500 Gr A/B/C, EN 10219 S235JRH/S355J2H, GB/T 6728 Q235B/Q355B, SS400, S275J0H Pre-Galvanized: Q195, Q235, S235GT, DX51D+Z
Outer Dimension (Square)	15×15mm – 600×600mm (Custom sizes available)
Wall Thickness	0.6mm – 30mm
Standard Length	5.8m, 6.0m, 11.8m, 12.0m, or Custom Cut-to-Length
Zinc Coating (HDG)	45-100 microns (Average 65-85μm), meetingISO 1461andASTM A123standards
Zinc Coating (Pre-Galvanized)	40-180 g/m² (Z40-Z180), equivalent to 6-25 microns
Surface Finish	Hot-Dip: Matte gray with spangle / Pre-Galvanized: Bright and smooth
Section Shape	Square / Rectangular (RHS)
Production Process	High-Frequency ERW Welded + Galvanizing
End Finish	Plain End / Grooved / Threaded (upon request)
Tensile Strength	315 – 550 MPa (Grade dependent)
Yield Strength	195 – 460 MPa (Grade dependent)
Elongation	≥20% – 30%
Standard Compliance	ASTM A500, EN 10219, JIS G3466, AS/NZS 1163, GB/T 6728, BS EN 10210

Hot Dip Galvanized vs. Pre-Galvanized Square Tube
Feature	Hot-Dip Galvanized (HDG) Square Tube	Pre-Galvanized Square Tube
Process	Tube is fully formed, then immersed in molten zinc bath	Steel strip is galvanized before tube forming
Zinc Coating Thickness	45-100 microns (average 65-85μm), meeting ISO 1461 & ASTM A123 standards	10-25 microns, providing economical corrosion protection
Coating Bond	Metallurgical bond between zinc and steel, extremely durable	Zinc coating applied to flat strip, weld seam may require touch-up
Corrosion Resistance	Superior, suitable for harsh outdoor environments (25-75+ years service life)	Good, suitable for indoor or mild environments
Surface Appearance	Matte gray with spangle pattern, slightly rough texture	Bright, smooth, uniform appearance
Cost	Higher initial cost, lower long-term maintenance	More economical upfront, ideal for budget-sensitive projects
Best Applications	Structural frames, outdoor fencing, marine environments, infrastructure projects	Furniture, indoor racking, automotive components, general fabrication

Common Square Tube Size Reference Chart
Outer Dimension (mm)	Common Wall Thickness Range (mm)	Typical Applications
20×20 – 50×50	1.0 – 3.0	Furniture frames, handrails, greenhouse structures, fencing
60×60 – 120×120	2.0 – 6.0	Structural supports, machinery frames, solar mounting systems
150×150 – 300×300	4.0 – 12.0	Heavy structural columns, bridge components, industrial frameworks
350×350 – 600×600	8.0 – 30.0	Large-scale construction, infrastructure projects, high-rise buildings

Key Features & Advantages

Premium Base Material: Manufactured from high-grade carbon steel strips (Q195, Q235, Q355, S235JR, S355J2H, ASTM A500 Gr B/C), ensuring excellent weldability, formability, and structural integrity.
Superior Corrosion Protection: Hot-dip galvanized tubes feature a thick, metallurgically bonded zinc coating (45-100μm) that provides exceptional resistance against rust and oxidation, significantly extending service life in outdoor and corrosive environments.
Precision Dimensional Tolerances: Outer dimension tolerance ±0.5%, wall thickness tolerance ±10%, meeting stringent international requirements for structural applications.
Clean & Smooth Interior/Exterior: Uniform square profile with smooth weld bead and consistent wall thickness, ensuring easy assembly and aesthetic appeal in exposed applications.
Wide Processing Capabilities: Available in standard mill lengths or custom cut-to-length sizes. We also offer drilling, punching, miter cutting, and welding services to meet specific fabrication requirements.
Quality Certifications: All products are manufactured under ISO 9001 certified quality management systems and are CE certified for European market compliance.

Company Profile

Quality Assurance & Mill Certificates

Comprehensive Testing: Each production batch undergoes rigorous inspection including chemical composition analysis, mechanical property testing (tensile, yield, elongation), dimensional accuracy verification, and zinc coating thickness measurement.
Zinc Coating Verification: Coating thickness is measured using magnetic induction gauges in compliance with ASTM E376 and ISO 2178 standards, ensuring full adherence to ISO 1461 and ASTM A123 requirements.
Documentation: All shipments include Mill Test Certificates (MTC) in compliance with EN 10204 3.1 or 3.2. We also provide Certificate of Origin (CO) , packing lists, and commercial invoices for seamless customs clearance.
Third-Party Inspection: We fully cooperate with pre-shipment inspections conducted by recognized agencies such as SGS, Bureau Veritas (BV), and Intertek to verify product quality and quantity before loading.

Applications & Typical Uses

Building & Construction: Structural columns and beams, roof trusses, scaffolding systems, purlins, and building frameworks for residential, commercial, and industrial projects.
Fencing & Security: Perimeter fencing posts, gate frames, security barriers, and handrail systems for public and private properties.
Agriculture & Greenhouses: Frame structures for greenhouses, livestock enclosures, irrigation system supports, and farm equipment frameworks.
Solar Energy: Ground-mounted solar panel racking systems, solar tracker supports, and photovoltaic mounting structures.
Industrial & Manufacturing: Machinery frames, conveyor systems, storage racking, workbench structures, and material handling equipment.
Infrastructure & Transportation: Bus shelters, signage poles, traffic barrier posts, and pedestrian bridge components.
Automotive & OEM: Trailer frames, truck body components, and custom original equipment manufacturing.

FAQ