Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of 40x40 steel box section 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.
Xi'an Dongmeng Group Co., Ltd. supplies 40x40 galvanized steel box section for structural fabrication, fencing, machinery frames, support structures, gates, railings and general engineering applications.
The 40 × 40 mm square hollow section, commonly called 40x40 SHS, 40mm box section or 40x40 square tube, is available in both pre-galvanized and hot-dip galvanized finishes.
Common wall thicknesses range from approximately 0.8 mm to 3.75 mm, depending on the galvanizing method, steel grade and required structural performance. Standard 6 m and 12 m lengths can be supplied together with cut-to-length processing.
For project purchasing, we can supply different steel grades, wall thicknesses, zinc coating requirements and fabrication services according to drawings or specifications.
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40x40 Steel Box Section Specifications
| Item | Specification |
| Product | 40x40 Galvanized Steel Box Section |
| Section Type | Square Hollow Section / SHS |
| Outside Size | 40 × 40 mm |
| Common Wall Thickness | 0.8–3.75 mm |
| Pre-Galvanized Thickness | Commonly 0.8–2.0 mm |
| Hot-Dip Galvanized Thickness | Commonly 1.5–3.75 mm |
| Standard Length | 5.8 m, 6 m, 11.8 m, 12 m |
| Custom Length | Available |
| Base Material | Carbon Steel |
| Common Grades | Q195, Q235, Q355, S235JRH, S355 grades |
| ASTM Option | ASTM A500/A500M structural tubing where specified |
| EN Option | EN 10219 structural hollow section where specified |
| JIS Option | JIS G3466 where specified |
| Manufacturing | ERW welded and formed square hollow section |
| Surface | Pre-Galvanized / Hot-Dip Galvanized |
| Processing | Cutting, drilling, punching, bending, welding and fabrication |
| Inspection | Dimensional, wall thickness, surface and coating inspection |
| Documentation | Material and inspection documentation according to order requirements |
Specifications should always be confirmed against the required project standard before ordering.
40x40 Box Section Weight and Thickness Chart
The following values are approximate theoretical weights calculated from the nominal dimensions. Actual weight can vary because of corner radius, manufacturing tolerance, wall thickness tolerance and coating mass.
| Size | Wall Thickness | Approx. Weight kg/m | Approx. Weight / 6 m |
| 40 × 40 mm | 0.8 mm | 0.98 | 5.91 kg |
| 40 × 40 mm | 1.0 mm | 1.22 | 7.35 kg |
| 40 × 40 mm | 1.2 mm | 1.46 | 8.77 kg |
| 40 × 40 mm | 1.5 mm | 1.81 | 10.88 kg |
| 40 × 40 mm | 2.0 mm | 2.39 | 14.32 kg |
| 40 × 40 mm | 2.5 mm | 2.94 | 17.66 kg |
| 40 × 40 mm | 3.0 mm | 3.49 | 20.91 kg |
| 40 × 40 mm | 3.75 mm | 4.27 | 25.61 kg |
For structural design, purchasing should be based on the section properties and tolerances specified by the applicable structural standard rather than theoretical weight alone.
How to Select 40x40 Box Section Wall Thickness
Wall thickness has a significant effect on weight, stiffness, weldability, cost and load capacity.
40x40x1.0–1.5 mm
Suitable mainly for light-duty fabricated products such as display frames, lightweight fencing, furniture frames, interior partitions and light agricultural fabrication.
These thinner sections are commonly supplied as pre-galvanized tubing.
40x40x2 mm
40x40x2 box section is one of the most common general-purpose specifications.
It offers a useful balance between weight, fabrication performance and stiffness and is frequently used for gates, fences, equipment frames, supports, light structures and welded assemblies.
40x40x2.5 mm
A better option where increased stiffness, welding allowance or higher service loads are required.
Typical applications include industrial frames, stronger fencing systems, support structures and fabricated equipment.
40x40x3 mm
40x40x3 steel box section is commonly selected for heavier fabricated frames, structural supports, outdoor structures and applications requiring greater resistance to bending or impact.
40x40x3.75 mm
Heavier wall sections can be supplied for projects requiring increased section strength, subject to production route and applicable dimensional standard.
The final wall thickness should be determined from engineering loads, span, connection details, corrosion environment and design code.
Pre-Galvanized vs Hot-Dip Galvanized 40x40 Box Section
The term "galvanized box section" can describe different manufacturing routes. Buyers should specify the required galvanizing method instead of purchasing based only on the word "galvanized."
| Feature | Pre-Galvanized 40x40 SHS | Hot-Dip Galvanized 40x40 SHS |
| Process | Formed from galvanized steel strip | Tube is formed first and then galvanized |
| Typical Wall | Lighter wall sections | Medium/heavier wall sections |
| Surface | Smooth and consistent | Heavier industrial galvanized appearance |
| Weld Area | Weld zone requires appropriate protection during manufacture | Finished section receives zinc coating after forming |
| Corrosion Protection | Suitable for many indoor/light outdoor applications | Better option for more demanding outdoor environments |
| Fabrication | Good for high-volume light fabrication | Suitable for structural/outdoor projects |
| Cost | Generally lower | Generally higher |
For coastal, humid, industrial or long-term exterior environments, coating specification should be selected according to the required corrosion exposure rather than simply choosing the cheapest galvanized finish.
Applicable Standards
A 40x40 steel box section can be supplied to different structural and coating requirements depending on the destination market and project specification.
ASTM A500/A500M
ASTM A500/A500M is commonly used for cold-formed welded and seamless carbon steel structural tubing in square, rectangular and round shapes.
Where ASTM A500 is specified, the structural tube requirements and the galvanized coating requirements should be defined separately.
EN 10219
EN 10219 is widely used for cold-formed welded structural hollow sections in European and international construction markets.
Grades such as S235 and S355 hollow-section steels may be available depending on the order.
JIS G3466
JIS G3466 covers carbon steel square and rectangular tubes used for general structural purposes.
GB/T Structural Hollow Section Standards
Q195, Q235 and Q355 carbon steel grades are widely used for square hollow-section products supplied from China.
Galvanizing Standards
The correct coating standard depends on how the product is manufactured.
Pre-galvanized tubing made from continuously zinc-coated steel strip may use galvanized flat steel compliant with standards such as ASTM A653/A653M or equivalent requirements.
For steel products galvanized after fabrication, specifications such as ASTM A123/A123M may be relevant where applicable.
The required structural standard, coating standard and coating mass or thickness should therefore be stated separately on the purchase order.
Why the Zinc Coating Specification Matters
Simply specifying "galvanized" is usually not enough for an industrial purchase order.
A buyer should define whether the project requires pre-galvanized material or galvanizing after forming, together with any required zinc coating mass, coating thickness, appearance or inspection method.
A lightweight interior frame and an outdoor structural frame exposed to rain, humidity or industrial atmosphere do not require the same corrosion-protection system.
Dongmeng Group can match the production route to the project environment and purchasing specification.
Main Applications of 40x40 Steel Box Section
Fencing and Gates
40x40 galvanized square tube is widely used as fence posts, gate frames, railing components and perimeter-security framing.
Solar and Equipment Support Frames
The square geometry makes the section easy to cut, locate, weld and connect into modular support frames.
Machinery Frames
40mm box section is suitable for guards, machine bases, equipment stands, conveyor frames and light industrial assemblies.
Agricultural Fabrication
Typical applications include greenhouse structures, equipment frames, gates, livestock fencing and agricultural support structures.
General Steel Fabrication
40x40 SHS is convenient for welded frames, brackets, work platforms, racks and custom fabricated assemblies.
Outdoor Structures
Hot-dip galvanized 40x40 sections are often selected where improved corrosion resistance is required for outdoor frames and support structures.
Fabrication and Custom Processing
Dongmeng Group can supply 40x40 square hollow section as mill-length material or as processed components ready for further fabrication.
Available processing includes:
Cut-to-Length: Custom lengths according to drawings or cutting lists.
Drilling: Bolt holes and connection holes according to specified position and diameter.
Punching: Efficient hole and slot processing for volume fabrication.
Bending: Suitable bending can be arranged subject to wall thickness, radius and dimensional requirements.
Welding: Fabricated frames and welded components can be produced according to project drawings.
Surface Finishing: Galvanizing, painting or other specified protection can be coordinated according to project requirements.
When requesting fabricated parts, send the drawing in PDF, DWG, DXF or STEP format where available.
Quality Control for 40x40 Galvanized SHS
Quality control should address both the steel section and the zinc coating.
Incoming material identification is checked against the ordered steel grade and specification.
During production, dimensional checks can include outside dimensions, wall thickness, length, straightness and section geometry.
The weld seam is inspected according to the applicable product specification and production requirements.
For galvanized products, coating appearance and coating thickness or mass can be checked according to the ordered coating requirement.
Finished material can also be inspected for cutting dimensions, fabrication accuracy, packaging and marking before shipment.
Third-party inspection can be arranged when required by the purchase contract.
Ordering 40x40 Steel Box Section
To prepare an accurate quotation, buyers should provide the required specification in a format similar to:
40 × 40 × 2.0 mm galvanized SHS, S235 grade, 6 m length, 10 metric tons, pre-galvanized, required zinc coating specified by buyer.
For structural projects, also provide the applicable standard, steel grade, coating requirement, quantity, destination port and any fabrication drawings.
This avoids the common problem of receiving quotations for products that look similar but use different steel grades, thickness tolerances or zinc coatings.
Packaging and Export
40x40 galvanized square tubes can be supplied in bundled export packaging suitable for container shipment.
Bundles can be secured using steel straps with suitable lifting and handling arrangements according to order requirements.
Custom identification marks, bundle labels and packing lists can be supplied for project purchasing and warehouse control.
Container loading plans can be prepared according to tube length, order quantity and destination requirements.
Why Choose Dongmeng Group
Xi'an Dongmeng Group Co., Ltd. supplies metal products for international industrial and project customers, with support covering material selection, dimensional specification, processing, inspection, packaging and export delivery.
Instead of quoting only a generic "40x40 galvanized tube," our team can match the offer to your required wall thickness, steel grade, galvanizing route, coating requirement, fabrication drawing and application environment.
This is particularly important for distributors, fabricators, EPC contractors, construction companies and OEM buyers purchasing repeat quantities.
Request a Quote
For an accurate quotation, send us:
40 × 40 mm required wall thickness
Steel grade or applicable standard
Pre-galvanized or hot-dip galvanized finish
Required length
Required zinc coating
Order quantity
Destination port
Processing drawings if applicable
Xi'an Dongmeng Group Co., Ltd.
Phone / WhatsApp: +86 15769214734
Email: office@dongmjd.com
Address: Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Hollow Structural Sections (HSS) are high-strength, cold-formed steel tubing with a square, rectangular, or round profile. Renowned for their exceptional strength-to-weight ratio, clean aesthetic lines, and versatile fabrication properties, HSS have become a fundamental component in modern construction, architecture, and manufacturing.
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Key Features & Benefits
Optimal Strength-to-Weight Ratio: The hollow design provides exceptional torsional rigidity and load-bearing capacity for its weight, resulting in strong yet lightweight structures.
Ease of Fabrication: Its symmetrical shape and consistent dimensions make it incredibly easy to cut, weld, drill, and machine, simplifying the fabrication process for both simple and complex projects.
Clean & Modern Aesthetics: The neat, square profile and smooth surfaces offer a clean, professional appearance that is ideal for applications where the steel is exposed.
Cost-Efficiency: As a standard and widely available size, the 40x40 SHS offers excellent value, making it an economical choice for a vast number of projects without sacrificing performance.
Durability: Made from robust mild steel, it provides reliable structural integrity. The optional galvanized finish ensures longevity even in challenging environments.
Available treatment processes
Cutting
Punching
Threading
Painting
We supply premium-grade square hollow section steel that guarantees consistent quality, precise tolerances, and excellent weldability. Our 40mm box section steel is sourced from reputable mills and is fully compliant with international standards.
Contact us today for a competitive quotation. We stock the 40x40 steel box section in various lengths and wall thicknesses, and can provide expert advice to ensure you select the perfect material for your application.
Our address
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Phone Number
+86 15769214734
FAQ
What is a 40x40 steel box section?
A 40x40 steel box section is a square hollow steel section with nominal external dimensions of 40 mm × 40 mm. It is also commonly called 40x40 SHS, 40mm square tube or 40mm box section.
What thickness is available for 40x40 box section?
Common wall thicknesses range from approximately 0.8 mm to 3.75 mm depending on the manufacturing method. Pre-galvanized products are commonly supplied in lighter walls, while hot-dip galvanized sections are often available in heavier wall thicknesses.
What is the weight of 40x40x2 box section?
The theoretical weight of a nominal 40 × 40 × 2 mm square section is approximately 2.39 kg/m before considering manufacturing corner geometry and tolerance. Actual commercial weight should be confirmed from the applicable standard and production data.
What is the weight of 40x40x3 box section?
The simple theoretical value is approximately 3.49 kg/m. Actual weight can vary according to corner radius, wall tolerance and manufacturing specification.
Is 40x40 galvanized box section suitable for outdoor use?
Yes. Galvanized steel provides improved corrosion resistance compared with uncoated carbon steel. The required coating system should nevertheless be selected according to the actual outdoor environment, expected service life and maintenance requirements.
What is the difference between 40x40 SHS and RHS?
SHS means Square Hollow Section, where the width and height are equal. A 40 × 40 mm section is therefore SHS. RHS means Rectangular Hollow Section and normally describes sections where the width and height are different.
Is 40x40 box section structural steel?
It can be supplied as structural tubing when manufactured to an appropriate structural standard such as ASTM A500/A500M, EN 10219, JIS G3466 or another specified standard. A dimensional size alone does not establish structural compliance.
Can you supply ASTM A500 40x40 square tubing?
ASTM A500/A500M square structural tubing can be supplied subject to grade, dimensional requirements and order quantity. Galvanizing requirements should be specified separately from the structural tubing standard.
Can 40x40 galvanized tube be welded?
Yes, but appropriate welding procedures and safety precautions are required for zinc-coated steel. Zinc coating near the weld area may need to be removed or repaired according to the fabrication and corrosion-protection specification.
Can you cut 40x40 box section to custom lengths?
Yes. Cut-to-length processing can be provided according to the required tolerance and cutting list.
Can holes and slots be added before shipment?
Yes. Drilling and punching can be carried out according to customer drawings. Hole dimensions, position tolerances and quantities should be included in the RFQ.
Is pre-galvanized tube the same as hot-dip galvanized tube?
No. Pre-galvanized tube is generally formed from steel strip that has already been continuously galvanized. Hot-dip galvanized tube is formed first and then zinc coated. The coating distribution, corrosion protection, appearance and cost can therefore differ.
Which wall thickness should I choose for a 40x40 steel box section?
The correct thickness depends on span, load, connection design, impact requirements and corrosion environment. Around 1.0–1.5 mm is generally associated with lighter fabrication, while 2.0–3.0 mm sections are frequently used for stronger frames and structural fabrication. Final selection should follow the project engineer's design requirements.
Can you provide inspection documents?
Material, dimensional and coating inspection documentation can be supplied according to the purchase specification. Third-party inspection can also be arranged when required.
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