What Is Mild Steel Square Hollow Section?
Mild steel square hollow section (SHS) is a hollow steel profile with a square cross-section, typically manufactured from low-carbon steel. With four sides of equal nominal width and a hollow interior, it is widely used in structural frameworks, support columns, machinery frames, and general fabrication.
| Section Type | Cross-Section | Typical Applications |
| SHS | Square | Structural frames, supports |
| RHS | Rectangular | Frames, beams, fabrication |
| CHS | Circular | Columns, tubular structures |
Key Advantages of Mild Steel Square Hollow Section
- Good Weldability
- Material Efficiency
- Structural Versatiliticknes
- Ease of Fabrication
- Wide Range of Applications
Mild Steel Square Hollow Section Sizes and Specifications
Mild steel square hollow sections are available in a range of outside dimensions and wall thicknesses to meet different structural and fabrication requirements. Selecting the right specification involves considering the section size, wall thickness, unit weight, and applicable product standard.
Common SHS Dimensions
Mild steel square hollow sections are specified by their outside width × outside height × wall thickness. Since SHS has a square cross-section, the outside width and height are equal. Common sizes include 20 × 20 mm, 40 × 40 mm, 50 × 50 mm, 100 × 100 mm, and 150 × 150 mm, with wall thicknesses selected according to structural and fabrication requirements.
The outside dimensions determine the overall size of the section, while wall thickness affects its weight and structural properties. Available combinations vary by manufacturer, product standard, and production range.
For a complete list of available outside dimensions and wall thicknesses, refer to our [Square Hollow Section Size Chart].
Wall Thickness and Unit Weight
Wall thickness affects the unit weight of mild steel square hollow sections. For the same outside dimensions, a thicker wall generally results in a higher weight per meter.
To estimate the theoretical weight of your steel pipe, use our [Pipe Weight Calculator — Unit Weight of Empty Pipes]. The calculator can help with preliminary material weight estimates based on the required pipe dimensions.
Mild Steel Grades and Manufacturing Standards
Mild steel square hollow sections are available in different steel grades and manufacturing standards. Buyers should consider yield strength, chemical composition, toughness, and project requirements when selecting a suitable grade.
Common Mild Steel Grades
| Steel Grade | Applicable Standard | Minimum Yield Strength* | Typical Applications |
| S235JRH | EN 10219 | 235 MPa | General structural frames and supports |
| S275J0H | EN 10219 | 275 MPa | Structural components requiring higher strength |
| S355J2H | EN 10219 | 355 MPa | Structural applications requiring higher strength |
*Minimum yield strength values apply to nominal wall thicknesses of 16 mm or less. Actual requirements depend on the applicable standard and product thickness.
Mild steel square hollow sections are generally manufactured from low-carbon steel. Under EN 10219, the maximum carbon content is 0.17% for S235JRH, 0.20% for S275J0H, and 0.22% for S355J2H. These values are standard limits rather than actual carbon content measurements for every batch.
EN 10219 vs. EN 10210
EN 10219 covers cold-formed welded structural hollow sections, while EN 10210 covers hot-finished structural hollow sections. Buyers should confirm the applicable standard, steel grade, dimensional tolerances, and inspection requirements before ordering.
Applications of Mild Steel Square Hollow Section
Mild steel square hollow sections (SHS) are used in structural fabrication where a uniform square profile, weldability, and practical assembly are important.
Mild Steel Square Hollow Section for Structural Steelwork
Mild steel square hollow section is used for columns, support frames, and roof structures. Section size, wall thickness, and steel grade must be selected according to load requirements and structural design calculations.
Mild Steel SHS for Machinery and Equipment Frames
The flat sides of mild steel SHS simplify the positioning and attachment of brackets, plates, and other components. It is commonly used for machine bases, equipment supports, and fabricated frames that require consistent profiles.
Square Hollow Section for Fencing and Gate Frames
Mild steel square hollow section provides a convenient profile for fence posts, gate frames, and railings. Wall thickness should suit the required rigidity and connection details, while outdoor installations may require galvanizing or protective coatings.
Mild Steel Square Hollow Section for Furniture and General Fabrication
Smaller mild steel SHS sizes are used for shelving, furniture frames, and display structures. Selection typically depends on the required dimensions, finished appearance, fabrication method, and intended service conditions.
Mild Steel Square Hollow Section vs. Other Steel Sections
Mild steel square hollow sections (SHS), rectangular hollow sections (RHS), and circular hollow sections (CHS) are widely used in structural fabrication and engineering. Their main differences lie in cross-sectional shape, which affects connection design, fabrication, and suitability for specific applications.
| Feature | SHS | RHS | CHS |
| Cross-section | Square | Rectangular | Circular |
| Main characteristic | Equal side dimensions | Unequal width and height | Round profile |
| Common applications | Frames, columns, supports | Frames, beams, brackets | Tubular structures, columns, handrails |
| Fabrication | Flat sides simplify many connections | Flat faces suit rectangular assemblies | Curved surface may require different connection details |
Mild Steel SHS vs. RHS
SHS has equal outside width and height, while RHS has a rectangular cross-section. SHS is often selected for square frames and supports, whereas RHS can suit designs requiring a wider or deeper profile.
The appropriate choice depends on structural calculations, available space, and connection requirements.
Mild Steel SHS vs. CHS
SHS has four flat sides, while CHS has a circular cross-section. SHS can simplify the attachment of plates and brackets, whereas CHS is useful in tubular structures where a round profile is preferred.
Their structural performance depends on dimensions, wall thickness, steel grade, and loading conditions.
Selection tip: Choose the section based on the required geometry, structural design, fabrication method, and applicable standards rather than cross-sectional shape alone.
FAQ
What is mild steel square hollow section used for?
Mild steel square hollow section is commonly used for structural frames, support columns, machinery frames, fencing, gates, furniture, and general fabrication. Its square profile provides flat surfaces for joining and attaching components.
What sizes are available for mild steel square hollow section?
Common outside dimensions include 20 × 20 mm, 40 × 40 mm, 50 × 50 mm, 100 × 100 mm, and 150 × 150 mm. Wall thickness and availability vary by manufacturer, product standard, and production range. Refer to a square hollow section size chart for available dimension combinations.
What is the difference between SHS and RHS?
SHS has a square cross-section with equal outside width and height, while RHS has a rectangular cross-section. SHS is suitable for square frames and supports, whereas RHS offers more flexibility when a wider or deeper profile is required.
