The Hybox 355 SHS 350x350x6.3 is a square hollow section reference for engineers, detailers, fabricators, and CAD users working with structural steel. This page brings together the section dimensions, corner geometry, sectional area, unit weight, applicable standard reference, and a DWG resource in one place.
Use the dimensional information below when reviewing layouts, preparing details, or comparing square hollow sections. Design resistance, connection performance, fabrication requirements, and member suitability must be verified for the specific project.
Hybox 355 SHS 350x350x6.3
Hybox 355 Square Hollow Sections
refer to : EN 10219-2:2006-04
the European standard that specifies tolerances, dimensions, and sectional properties for cold-formed welded structural hollow sections made of non-alloy and fine grain steels. It complements EN 10219-1, which covers technical delivery conditions.
Dimension : 350x350x6.3
Depth : 350 mm
Width : 350 mm
Thickness : 6.3 mm
Outer Corner Radius : 15.8 mm
Inner Corner Radius : 9.4 mm
Sectional Area : 85.2 cm2
Unit Weight : 66.9 kg/m
How to read the SHS reference
SHS means square hollow section. Its nominal depth and width are equal, while the wall thickness describes the steel thickness around the hollow interior. The listed corner radii describe the outside and inside transitions between the flat faces. These radiused corners are part of the section geometry and should be considered when checking clearances, connection details, or CAD representations.
Section properties and weight
The source data lists the sectional area and unit weight for this Hybox 355 section. Sectional area is a geometric property used in calculations such as axial resistance and self-weight assessment, subject to the applicable design method and material information. Unit weight supports estimating the member’s line load and material quantity. These values should be kept distinct from design resistance, which also depends on material, stability, loading, restraint, and connection conditions.
Standard reference and product identification
The reference identifies EN 10219-2:2006-04 for tolerances, dimensions, and sectional properties of cold-formed welded structural hollow sections. The source also distinguishes this dimensional and property reference from the related technical delivery requirements described for EN 10219-1. When using this page for procurement or design coordination, confirm the required material specification, delivery documentation, tolerances, and project requirements with the responsible engineer or supplier.
CAD and drafting workflow
The downloadable DWG can support preliminary detailing, layout work, and coordination. Before issuing a fabrication or construction drawing, check the drawing units, section orientation, corner representation, layer conventions, and any project-specific drafting requirements. Related SteelSTD resources on structural steel shapes, SHS terminology, section properties, and steel connection detailing can provide useful context for reviewing this section.
Frequently asked questions
What does SHS mean?
SHS means square hollow section. It describes a hollow structural steel profile with square nominal outside dimensions and a wall thickness.
What do 350x350x6.3 describe?
These values identify the section’s nominal depth, nominal width, and wall thickness, respectively. The source lists the corresponding dimensions individually for clarity.
Why are both outer and inner corner radii listed?
The two radii describe the outside and inside corner transitions of the welded hollow section. They help represent the actual section shape more accurately than a sharp-cornered square.
What is the DWG file used for?
The DWG is a CAD reference for drafting and coordination. It should be checked against the project standard and supplier information before being used for fabrication or issued construction documentation.
Does the listed unit weight establish design capacity?
No. Unit weight describes the member’s mass per unit length. Structural capacity requires a separate engineering assessment that considers the section, material, loading, stability, restraints, and connections.
