Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of Stainless Steel Square Tube Supplier in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
Stainless Steel Square Tube Manufacturer and Price Guide
Dongmeng Group manufactures and supplies stainless steel square tubes for architectural metalwork, equipment frames, railings, furniture, food machinery, transportation systems and custom fabrication.
Our square tubing is available in multiple stainless steel grades, wall thicknesses and surface finishes. We support full-length tubes, fixed-length cutting, laser processing, drilling, welding, bending and drawing-based OEM components.
What Is Stainless Steel Square Tube?
Stainless steel square tube is a hollow section with four equal sides and rounded or controlled-radius corners.
It is most commonly manufactured from stainless steel strip using automatic roll forming and longitudinal welding. The welded tube is then calibrated to the specified square dimensions, straightened, cut and finished.
ASTM A554 is the main international specification used for ornamental and mechanical stainless steel square tubing. The current ASTM A554-26 covers austenitic, ferritic, martensitic and duplex stainless steel mechanical tubes supplied in square, rectangular, round or special shapes. It covers outside dimensions up to 16 inches, or 406.4 mm, and wall thicknesses of 0.020 inches, or 0.51 mm, and above.
Square tube should be ordered by:
Outside Width × Outside Height × Wall Thickness × Length
Example:
50 × 50 × 2.0 × 6000 mm
Do not specify ordinary square tubing only by diameter, nominal pipe size or pipe schedule.
Stainless Steel Square Tube Specifications
| Parameter | Typical Supply Specification |
| Product Type | Welded stainless steel square mechanical tube |
| Grades | 201, 304, 304L, 316, 316L and 430 |
| Other Grades | Available after mill feasibility review |
| Primary Standard | ASTM A554-26 |
| Optional Japanese Standard | JIS G 3446:2022, subject to order specification |
| Typical Side Dimension | 10–300 mm |
| ASTM A554 Scope | Up to 406.4 mm outside dimension |
| Typical Wall Thickness | 0.8–8.0 mm |
| ASTM A554 Wall Scope | 0.51 mm and above |
| Standard Length | 5.8, 6, 11.8 or 12 m |
| Custom Length | Fixed-length cutting available |
| Manufacturing Route | Automatic welded and roll formed |
| Supply Condition | As-welded, annealed, cold formed or cold reduced |
| Surface | Mill, 2B, BA, No.4, satin, hairline or mirror |
| Finished Sides | Four-side polishing available |
| Grain Direction | Longitudinal |
| Weld Bead | As-welded, external removed or fully finished |
| Corner Options | Standard radius or drawing-controlled radius |
| Edge Condition | Saw-cut, deburred or machined |
| Protection | Film, sleeves, wrapping and wooden cases |
| Documentation | MTC, inspection report and Certificate of Conformity |
JIS G 3446:2022 applies to stainless steel tubes used for machinery, automobiles, furniture, apparatus, other mechanical parts and structures. It should be specified separately rather than described as automatically equivalent to ASTM A554.
Final production capability must be confirmed according to grade, outside dimensions, wall thickness, finish, tolerance and order quantity.
Common Square Tube Sizes
| Outside Size | Common Wall Thicknesses | Typical Uses |
| 10 × 10 mm | 0.8–1.5 mm | Decorative trim and light components |
| 15 × 15 mm | 0.8–1.5 mm | Furniture and display frames |
| 20 × 20 mm | 1.0–2.0 mm | Furniture, guards and light frames |
| 25 × 25 mm | 1.0–2.5 mm | Railings, frames and equipment |
| 30 × 30 mm | 1.0–3.0 mm | Architectural and fabrication work |
| 40 × 40 mm | 1.2–4.0 mm | Equipment frames and handrails |
| 50 × 50 mm | 1.5–5.0 mm | Structural frames and supports |
| 60 × 60 mm | 1.5–5.0 mm | Machinery and architectural projects |
| 80 × 80 mm | 2.0–6.0 mm | Heavy frames and support systems |
| 100 × 100 mm | 2.0–8.0 mm | Industrial frames and columns |
| 150 × 150 mm | 3.0–8.0 mm | Large structural components |
| 200 × 200 mm | Project-specific | Heavy fabrication |
| 300 × 300 mm | Project-specific | Large custom hollow sections |
These are common commercial combinations rather than guaranteed stock sizes. Exact availability should be confirmed before quotation.
Available Stainless Steel Grades
| Grade | Main Characteristics | Recommended Applications |
| 201 | Low-nickel economical austenitic grade | Dry indoor furniture, displays and decorative frames |
| 304 | General-purpose corrosion resistance and good fabrication | Railings, architectural work, machinery and food equipment |
| 304L | Low-carbon version for extensive welding | Welded frames and fabricated assemblies |
| 316 | Molybdenum-alloyed grade with increased corrosion resistance | Chemical, food and humid-environment equipment |
| 316L | Low-carbon molybdenum grade | Coastal, process, pharmaceutical and welded equipment |
| 430 | Economical magnetic ferritic grade | Mild indoor environments and appliance structures |
Grade 304 is a widely used chromium-nickel stainless steel for general indoor and mild outdoor applications, including handrails, window frames, equipment and architectural components.
Grade 316L contains molybdenum and is generally selected where corrosion-resistance requirements are higher than average, including many process, food, pharmaceutical and chemical applications.
Grade 430 is a ferritic stainless steel typically used in mildly corrosive and indoor environments.
The final grade must be selected according to actual exposure, chloride level, temperature, cleaning chemicals, fabrication and expected service life.
ASTM A554 vs ASTM A312
| Item | ASTM A554 | ASTM A312 |
| Main Product | Stainless steel mechanical tubing | Austenitic stainless steel pressure pipe |
| Common Shape | Round, square, rectangular and special | Primarily round pipe |
| Dimension Method | Outside dimension × wall thickness | NPS and schedule |
| Typical Uses | Architectural, mechanical, ornamental and structural components | High-temperature and corrosive fluid service |
| Manufacturing Route | Automatically welded without filler metal | Seamless, welded or heavily cold-worked welded |
| Pressure Qualification | Not automatically pressure rated | Intended for pipe service subject to design code |
| Best Standard for Square Tube | Yes | No |
ASTM A312 covers austenitic stainless steel pipe for high-temperature and general corrosive service and uses standardized pipe dimensions associated with ASME B36.19. It should not be presented as the primary specification for ordinary square mechanical tubing.
Surface Finishes
| Finish | Appearance | Typical Applications |
| Mill Finish | Industrial untreated appearance | Hidden frames and fabricated structures |
| 2B | Smooth gray cold-rolled surface | Equipment and general fabrication |
| BA | Bright and lightly reflective | Furniture and decorative components |
| No.4 Brushed | Uniform satin directional grain | Railings, kitchens and architectural frames |
| Hairline | Fine continuous linear grain | Premium doors, furniture and interior projects |
| Mirror | Highly reflective decorative surface | Luxury interiors and display systems |
| Sandblasted | Soft low-gloss texture | Architectural and design applications |
| PVD Colored | Black, gold, bronze or other decorative colors | Hotels, retail and premium furniture |
For appearance-sensitive projects, the purchase order should specify:
Approved physical finish sample
Surface finish on two or four sides
Grain direction
Required roughness when applicable
Weld position
Weld-bead removal level
Corner radius
Protective-film type
Acceptable scratch and dent criteria
Same-batch production requirement
A finish name alone does not guarantee an identical visual appearance between different mills or polishing lines.
Weld-Bead Options
The weld condition has a significant effect on appearance, inside clearance and price.
As-Welded
The internal weld bead remains and the outside surface receives only basic finishing. This is generally the most economical option for hidden structures.
External Weld Bead Removed
The external weld is ground or planished to create a smoother visible face. The internal weld bead remains.
Internal and External Weld Bead Finished
Both sides of the weld are processed when internal clearance, hygiene or appearance is important. Availability depends on tube size and wall thickness.
The required weld-bead condition must be stated before quotation.
Manufacturing Process
A typical production process includes:
Stainless steel coil and grade verification
Precision slitting to the required strip width
Progressive roll forming
Automatic longitudinal welding without filler metal
Weld-bead processing when specified
Square forming and dimensional calibration
Heat treatment or cold reduction when required
Straightening and fixed-length cutting
Surface grinding or polishing
Dimensional and visual inspection
Protective-film or sleeve application
Export packing and marking
ASTM A554 requires welded mechanical tubes to be produced from flat-rolled steel using an automatic welding process without added filler metal.
Square tubing may be formed directly from strip or reshaped from welded round tubing, depending on the size, finish and production line.
Stainless Steel Square Tube Price
There is no single reliable price per metre or per tonne for every stainless steel square tube.
The final price depends on:
Stainless Steel Grade
201, 304, 316L and 430 have different alloy content and raw-material costs. Grade 316L is normally priced above 304 because of its nickel and molybdenum content.
Outside Size and Wall Thickness
Larger sections and thicker walls increase weight per metre and raw-material consumption.
Surface Finish
Mill-finish or 2B tubing is generally less expensive than four-side No.4, hairline, mirror or PVD-finished tubing.
Weld-Bead Condition
Internal weld removal, external polishing and tight bead-height control require additional production steps.
Dimensional Tolerance
Tight control of side dimension, wall thickness, straightness, twist, corner radius and squareness can increase processing and inspection costs.
Order Quantity
Larger production quantities generally reduce the forming, tooling, setup and packaging cost allocated to each metre.
Custom Fabrication
Laser cutting, drilling, slots, mitre cutting, bending, welding and assembly are quoted separately.
Inspection and Documentation
PMI, additional mechanical testing, third-party inspection and project documentation can affect the quotation.
Packaging and Delivery
Individual sleeves, wooden cases, sea freight, destination charges and Incoterms must be included in the commercial comparison.
A transparent quotation should therefore identify:
Material Cost + Tube Forming + Surface Finish + Fabrication + Inspection + Packaging + Freight
Estimated Square Tube Weight
For preliminary purchasing calculations, the theoretical weight of a square stainless steel tube can be estimated with:
Approximate Weight, kg/m = 0.0317 × Wall Thickness × (Outside Width − Wall Thickness)
Where:
Outside width is in millimetres
Wall thickness is in millimetres
The calculation assumes an approximate stainless steel density of 7.93 g/cm³
The effect of corner radius and weld geometry is not included
Final order weight should be based on the mill's theoretical-weight method or actual shipment weight.
Custom Fabrication Services
Dongmeng Group can supply full tubes or finished components according to customer drawings.
Available services include:
Fixed-length saw cutting
Laser tube cutting
Hole and slot processing
Mitre cutting
End notching
CNC drilling and tapping
Tube bending
Frame welding
Surface grinding
Weld blending
Brushing and polishing
PVD decorative coating
Component assembly
Custom labels and kits
For OEM components, provide CAD drawings or PDF drawings showing dimensions, tolerances, weld requirements and surface-finish direction.
Structural and Pressure-Service Notice
ASTM A554 is a mechanical-tubing specification. Compliance with ASTM A554 alone does not establish the load-bearing capacity of a finished structure.
For safety-critical structural projects, the purchaser or project engineer should specify:
Design code
Required grade and condition
Mechanical-property requirements
Section dimensions
Wall-thickness tolerances
Weld requirements
Connection design
Load combinations
Inspection level
Required certification
Ordinary stainless steel square mechanical tubing is also not automatically pressure rated. Do not use NPS or schedule-based pressure values unless the complete product, manufacturing standard and engineering design have been approved for the pressure application.
Typical Applications
Stainless steel square tubes are widely used for:
Architectural railings
Balustrades and guardrails
Entrance structures
Doors and window frames
Furniture frames
Shelving and retail displays
Commercial kitchen equipment
Food-processing equipment
Machinery frames
Equipment guards
Conveyor systems
Vehicle and transportation components
Solar-panel support frames
Signage structures
Hotel and shopping-centre decoration
Chemical and pharmaceutical equipment
Custom welded assemblies
Grade, wall thickness and surface finish should be selected according to the real installation environment and engineering load.
Quality Inspection
Inspection can be carried out according to the purchase specification and approved sample.
Our quality-control process may include:
Stainless steel grade and heat-number verification
Mill Test Certificate review
Outside-dimension measurement
Wall-thickness inspection
Squareness and diagonal measurement
Corner-radius inspection
Straightness and twist inspection
Weld-seam and bead-height inspection
Surface-finish comparison
Scratch, dent and contamination inspection
Fixed-length and processed-part measurement
Packaging and identification inspection
Optional services include PMI, tensile testing, hardness testing, surface-roughness measurement and third-party inspection.
Packaging and Export Protection
Packaging can include:
PE or PVC film on polished surfaces
Individual plastic sleeves
Paper or foam separators
Waterproof wrapping
Steel-strapped bundles
Reinforced wooden pallets
Fully enclosed wooden cases
Plastic end caps
Heat-number and dimension labels
Customized shipping marks
Polished and mirror-finished tubes should be separated during packing to reduce friction scratches.
Why Choose Dongmeng Group?
Dongmeng Group provides stainless steel material supply, welded-tube manufacturing, surface finishing, quality inspection and drawing-based fabrication.
The company profile lists five manufacturing centers, 18 production lines, 10 warehouses and 588 employees. Its facilities include a welded steel pipe production center, profile and bar production center, material inspection capabilities and export-logistics support.
Customers can receive:
Multiple stainless steel grades
Standard and custom square-tube dimensions
Mill, brushed and polished surfaces
Drawing-based fabrication
Weld and corner-detail control
Finish samples before production
MTC and inspection documentation
Third-party inspection support
Custom export packaging
FOB, CFR, CIF and DDP delivery support
Request a Square Tube Price
For an accurate quotation, please provide:
Stainless steel grade
Outside width and height
Wall thickness
Required length
Quantity
Surface finish
Finished sides
Weld-bead requirement
Corner-radius requirement
Dimensional tolerance
Fabrication drawing
Packaging requirement
Destination port or delivery address
Company: Dongmeng Group
Email: office@dongmjd.com
Phone / WhatsApp: +86 157 6921 4734
Website: www.cndmmetal.com
Frequently Asked Questions
Is stainless steel square pipe the same as square tube?
The terms are often used interchangeably in commercial searches. Technically, square hollow products are normally specified as tubing by outside dimensions and wall thickness rather than by nominal pipe size and schedule.
Which standard applies to stainless steel square tube?
ASTM A554 is the primary standard for welded stainless steel mechanical tubes in square, rectangular, round and special shapes.
Can ASTM A312 be used for square tube?
ASTM A312 is primarily a pressure-pipe standard for round austenitic stainless steel pipe. It should not be used as the default specification for ordinary square mechanical tubing.
Is seamless stainless steel square tube available?
Special seamless hollow sections may be produced by cold drawing or reshaping seamless round hollows. They are not as widely available as welded ASTM A554 square tubing and require a mill feasibility review.
What is the most common grade?
Grade 304 is the most common general-purpose choice for architectural, mechanical, food-equipment and furniture applications.
When should I choose 316L?
316L should be considered when the installation has higher corrosion-resistance requirements, including humid, coastal, process or chemically aggressive conditions. Final suitability depends on the complete environment.
Can all four sides be polished?
Yes. Four-side No.4, satin, hairline and mirror polishing can be supplied. The required finish sample and grain direction should be confirmed before production.
Can you remove the internal weld bead?
Internal weld-bead removal is available for selected dimensions. Feasibility depends on the tube size, wall thickness and required internal finish.
How is the price calculated?
Pricing depends on grade, theoretical or actual weight, size, wall thickness, finish, weld condition, tolerance, quantity, fabrication, packaging and delivery.
Can you manufacture components from drawings?
Yes. Dongmeng Group can provide cutting, drilling, laser processing, bending, welding, polishing and assembly according to customer drawings.
What documents can be supplied?
Available documents include MTC, Certificate of Conformity, dimensional reports, PMI reports, inspection reports and third-party inspection documentation.
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