Square Steel Pipe Manufacturer & Supplier – Sino East Steel Group
Sino East Steel Group is a professional square steel pipe manufacturer and supplier headquartered in Tianjin, China. Since 2008, we have exported square and rectangular steel tubes (SHS/RHS) to more than 80 countries across the Middle East, Southeast Asia, Africa, Europe and the Americas. As a factory-direct supplier, we eliminate middleman costs and deliver certified square steel pipes at competitive wholesale prices, with MOQ starting from 5 tons and a standard 15–25 day delivery window.
Square and rectangular hollow sections are produced by cold-forming steel strip into a tubular shape and welding the longitudinal seam with high-frequency electric resistance welding (ERW). The result is a strong, lightweight structural member with excellent strength-to-weight ratio, uniform corners and consistent wall thickness, making it one of the most versatile products in modern steel construction. For a full overview of hot-dip vs electro-galvanized square tube product categories, see our classification guide. Our plant covers 50,000 m² with dedicated forming, welding, sizing, straightening and galvanizing lines, supporting an annual output of over 80,000 tons of square and rectangular tubes. Our export department handles more than 300 containers of steel pipes and tubes every month, giving us the experience and capacity to serve both repeat distributors and first-time overseas buyers with equal reliability.
Why Choose Sino East Steel Group as Your Square Pipe Supplier?
International buyers evaluate a square steel pipe supplier on four factors: product quality, certification, price stability and delivery reliability. The following sections explain how Sino East Steel Group performs on each of them, and why thousands of global buyers choose us as their long-term square steel tube manufacturer and supplier.
1. Factory-Direct Manufacturing, No Middlemen
We are not a trading company. Our factory directly controls the entire process from steel strip purchasing, slitting, cold forming, high-frequency welding, sizing and straightening to final inspection and, when required, hot-dip galvanizing. This vertical integration allows us to offer prices that are typically 5–10% lower than trading companies while maintaining consistent quality, because there is no broker margin in the supply chain. When you buy from Sino East Steel Group, you buy directly from the production source, which also means faster communication, faster quotations and faster problem-solving during the whole cooperation period.
2. Full International Standards Compliance
Our square and rectangular tubes are manufactured and tested according to internationally recognized standards, including ASTM A500, EN 10219, EN 10210, JIS G3466, GB/T 6728 and AS/NZS 1163. Each batch is accompanied by a mill test certificate (MTC) with chemical composition and mechanical property data, allowing customs clearance and third-party inspection to proceed smoothly. Our quality management system is certified to ISO 9001:2015, and our export documentation team is experienced in preparing certificates of origin and all shipping documents needed for letter of credit transactions.
3. Stable Quality with Multi-Step Inspection
Quality is built through process control, not just final inspection. Our quality control system covers five key checkpoints: incoming raw material verification, forming and welding parameters, weld seam NDT, dimensional and corner-radius measurement and surface quality inspection. Every production lot undergoes chemical analysis, tensile testing, flattening tests, bend tests and weld seam eddy current testing in accordance with the requested standard. We also accept third-party inspection by SGS, BV or Intertek before shipment, at the buyer’s request, and we welcome overseas buyers to visit our factory in Tianjin to witness the production process in person.
4. Flexible Supply for All Project Scales
From a 5-ton trial order for local distributors to 4,000-ton infrastructure project deliveries, our production scheduling and warehouse stock (normally 8,000–12,000 tons of finished tubes) allow us to support urgent orders and staggered deliveries across multiple shipments. Our sales engineers work with buyers to split large orders into weekly or monthly delivery schedules, which reduces the buyer’s warehousing cost and keeps construction sites running without interruption. For project tenders, we can also provide pre-qualification documents, technical datasheets and reference lists from completed projects.
Square Steel Pipe Product Range
Black Square & Rectangular Steel Tube (ERW)
Black square and rectangular tubes are produced by high-frequency ERW welding of cold-formed strip, with the mill scale surface left as-is for further processing. They are the economical workhorse of steel structures, agricultural equipment, vehicle manufacturing and general fabrication. Black SHS/RHS are normally supplied in lengths of 6 m or 12 m, with sharp or semi-sharp corners, and can be painted, powder-coated or galvanized by the buyer after fabrication. Popular applications include machine frames, storage racks, gates, fencing and structural columns, where the tube is cut, drilled and welded on site.
Galvanized Square & Rectangular Steel Tube
Galvanized square and rectangular tubes are hot-dip galvanized after forming, providing a zinc coating of 45–85 μm that protects the tube from corrosion for 15–30 years in outdoor environments. They are the preferred choice for solar panel mounting structures, greenhouse frames, fence posts, guardrails, billboard frames and outdoor playground equipment. Galvanized SHS/RHS eliminate the need for field painting and maintenance, which reduces the total installed cost of outdoor structures over their service life. We also offer pre-galvanized square tube with a thinner, smoother coating for indoor applications where a bright finish is preferred.
Precision Square Tube (Cold Drawn)
For machinery and precision applications, we supply cold-drawn square tubes with tighter dimensional tolerances and a smoother surface finish. Precision square tube is used in hydraulic cylinders, sliding guides, telescopic arms, furniture mechanisms and automotive components, where consistent dimensions directly affect assembly quality. Tolerances can be held to ±0.1 mm on outer dimensions and wall thickness, and the drawn surface is scale-free and ready for chrome plating or hard-coating processes.
Large-Dimension Square & Rectangular Tube
For heavy structural projects we supply large-dimension SHS/RHS up to 400×400 mm and rectangular sections up to 500×300 mm, with wall thicknesses up to 20 mm. Large hollow sections are increasingly specified for high-rise buildings, stadium roofs, bridge girders and heavy machinery bases, where their high torsional stiffness and clean appearance reduce steel weight compared to open sections such as I-beams or channels. Large sections can be supplied with beveled ends for full-penetration field welds, and we provide cutting, drilling and end-plate welding services on request.
Square Steel Pipe Specifications
| Parameter | Available Range |
|---|---|
| Square Section | 15×15 mm to 400×400 mm |
| Rectangular Section | 20×10 mm to 500×300 mm |
| Wall Thickness | 0.5 mm – 20.0 mm |
| Standard Length | 6 m, 12 m (21 ft), or custom cut |
| Process | ERW (High-Frequency), Cold Drawn |
| Standards | ASTM A500, EN 10219, EN 10210, JIS G3466, GB/T 6728, AS/NZS 1163 |
| Steel Grade | Q195, Q215, Q235, Q345, S235JR, S355JR, A500 Gr.B/C |
| Corner Type | Sharp Corner, Semi-Sharp Corner, Round Corner |
| Surface Finish | Black (mill scale), Hot-Dip Galvanized, Pre-Galvanized, Oiled |
| Certification | ISO 9001, Mill Test Certificate, SGS/BV/Intertek inspection available |
Typical Weight Reference (Square Tube, 6 m)
| Section (mm) | Wall (mm) | Weight (kg/m) | Weight (kg/6m) |
|---|---|---|---|
| 20×20 | 1.5 | 0.87 | 5.22 |
| 40×40 | 2.0 | 2.39 | 14.34 |
| 50×50 | 2.5 | 3.74 | 22.44 |
| 60×60 | 3.0 | 5.37 | 32.22 |
| 80×80 | 4.0 | 9.56 | 57.36 |
| 100×100 | 5.0 | 14.92 | 89.52 |
| 120×120 | 6.0 | 21.49 | 128.94 |
| 150×150 | 6.0 | 27.15 | 162.90 |
Typical Applications of Square Steel Pipe
- Steel structures – columns, beams, trusses, purlins, portal frames, mezzanine floors
- Solar & renewable energy – solar panel mounting frames, tracker structures, wind tower internals
- Agriculture – greenhouse frames, irrigation supports, livestock pens, farm gates
- Transportation – trailer frames, container chassis, vehicle bumpers, racking systems
- Furniture & retail – display racks, shelving systems, table and chair frames, lockers
- Construction & infrastructure – handrails, guardrails, street furniture, sign posts, fencing
Square Tube vs. Round Pipe: Which Section Should You Choose?
Square and rectangular hollow sections are increasingly replacing round pipe and open sections in structural applications because of their superior bending stiffness and easier connection detailing. For the same weight per meter, a square section offers higher bending resistance about the flat faces and significantly better torsional rigidity than a round pipe of similar diameter, which is why SHS is preferred for columns and moment frames. Square sections also simplify connections: flat faces allow direct bolting, welding and clamping without saddles or fishplates, reducing fabrication labor on site. Round pipe remains the better choice for fluid transport, where pressure containment and flow efficiency matter, and for applications requiring omnidirectional bending. For structural framing, racking, fencing and architectural work, square and rectangular tube almost always wins on both performance and installed cost. Our engineers help buyers convert structural designs between round and square sections with section-property calculations, ensuring the substitution meets the design loads before quotation.
How We Ensure Reliable Export Service
Export Experience Across 80+ Countries
Since our first export shipment in the 1990s, we have delivered square and rectangular steel tubes to distributors, fabricators and project owners in the Middle East, Southeast Asia, Africa, South America, Europe and North America. Our team understands the documentation, packaging and shipping requirements of different destination countries, including the Middle East SASO/IECEE certification requirements, the European CE marking requirements and the African market’s preference for bundled, waterproof-packed tubes suitable for long sea voyages and tropical climates.
Professional Export Documentation
Every export order is supported by a complete documentation set: commercial invoice, packing list, bill of lading, mill test certificate, certificate of origin (CO or COO), and, where applicable, insurance certificate and pre-shipment inspection report. For letter of credit (L/C) transactions, our documentation team ensures that all documents are presented exactly as required by the L/C terms, minimizing the risk of discrepancies and payment delays.
Flexible Payment and Incoterms
We support flexible payment terms including T/T (30% deposit and 70% balance before shipment), L/C at sight for large orders, and in some cases D/P for established customers. Regarding incoterms, we quote on EXW, FOB Tianjin, CFR or CIF basis according to the buyer’s preference, and our logistics partners provide competitive sea freight rates to major ports worldwide, including Jebel Ali, Rotterdam, Singapore, Lagos, Mombasa and Santos.
Pricing, MOQ & Delivery
- Price Range: USD 480 – 850 per ton (FOB Tianjin), depending on section size, wall thickness, surface finish (black vs galvanized) and order quantity. We provide a firm quotation within 24 hours.
- MOQ: 5 tons for stock sizes; 20 tons for customized specifications.
- Payment Terms: T/T (30% deposit, 70% before shipment) or L/C at sight for large orders.
- Delivery: 15–25 days after deposit, depending on quantity and destination port.
- Packing: Hexagonal bundles with steel straps, waterproof wrapping, or wooden crates for small sections.
- Port of Loading: Tianjin Xingang Port, China (nearest port to our factory).
Buyer’s Guide: How to Choose a Reliable Square Pipe Supplier
Choosing the right supplier is as important as choosing the right product. A reliable square steel pipe supplier should be able to answer five questions clearly: First, what standard is the tube actually manufactured and tested to, and can the supplier provide the mill test certificate? Second, what are the exact outer dimensions, wall thickness and corner configuration, and how tight are the tolerances? Third, for galvanized tube, what is the zinc coating thickness in microns? Fourth, what is the actual lead time from deposit to port of loading? And fifth, what happens if the quality does not meet the contract specification after arrival? At Sino East Steel Group, we answer all five questions in writing within 24 hours of your inquiry, and we stand behind every shipment with a clear quality guarantee. We recommend every buyer request a mill test certificate with each shipment and, for large orders, arrange third-party inspection before shipment to protect both parties’ interests.
How to Get a Quotation
To receive an accurate factory quotation within 24 hours, please provide the following information: (1) section size (width × height) and wall thickness, (2) length and quantity, (3) standard and steel grade, (4) surface finish (black, hot-dip galvanized, or pre-galvanized), and (5) destination port. Our export sales engineers will confirm availability, price and delivery schedule, and send you a formal proforma invoice with mill test certificate samples.
Frequently Asked Questions (FAQ)
Q1: What is the difference between SHS and RHS square tube?
SHS means square hollow section, where width and height are equal. RHS means rectangular hollow section, where width and height differ. Both are produced by the same ERW process and are covered by standards such as ASTM A500 and EN 10219.
Q2: What is the difference between black and galvanized square tube?
Black square tube has a mill-scale surface and is used where the tube will be painted, powder-coated or protected by the surrounding structure. Galvanized square tube has a zinc coating (45–85 μm) applied by hot-dip galvanizing, providing 15–30 years of outdoor corrosion protection without maintenance painting.
Do you supply 100×100 square hollow section (SHS)?
Yes — see our 100×100 steel hollow section page with weight charts and factory pricing.
Q3: Can you supply galvanized square tube with a specific zinc coating thickness?
Yes. We can supply hot-dip galvanized tube with coating thickness from 45 μm to 85 μm per your project specification, and each batch can be verified by coating thickness measurement with the mill test certificate.
Q4: Do you provide cutting, drilling or custom lengths?
Yes. We can supply custom lengths, cut-to-size pieces, drilled and punched sections, and beveled ends for welding. Please provide your fabrication drawings for a firm quotation.
Q5: What is the MOQ for square steel tube?
Our MOQ is 5 tons for standard stock sizes and 20 tons for customized specifications. Trial orders help buyers verify our quality and delivery before committing to larger volumes.
Q6: Do you supply square tube for solar mounting and greenhouse projects?
Yes. We are a regular supplier of hot-dip galvanized square tube to solar mounting and greenhouse projects worldwide, with competitive pricing on high-volume project quantities and fast delivery scheduling.
Contact Sino East Steel Group today – our sales engineers will respond with a factory-direct quotation and technical support within 24 hours.
How much weight can square steel tubing hold?
See our square steel tubing weight capacity guide with load charts for common sizes.
What gauge steel tubing should I use?
Find the answer in our steel tubing gauge selection guide.