Strongbox cold formed hollow sections
Specification details

US_EN-Construction-Product-Strongbox cold formed hollow sections | Key product features

Key product features

General hollow sections - Strongbox® 235

Key features

  • Excellent quality, made with steel from a high quality production process
  • Minimum strength of 235 MPa
  • High levels of formability and, because the steel is fully-killed, excellent weldability
  • Product subject to non-specific inspection and testing; with test report supplied
  • Excellent consistent dimensional tolerances
  • Excellent supply availability through approved stockholders
  • Suitable for galvanising

EN_US-Construction-Product-Tubes-Strongbox-Dimensional tolerancesTSE

Dimensional tolerances

 

 Circular Square/Rectangular 
Outside dimension
(D B and H)
±1% with a min of ±0.50mm
and a max of ±10mm
Side length (mm)

H,B < 100


100 ≤ H,B

H,B > 200
Tolerance

±1% with a min of
±0.5mm

±0.8%

±0.6%
Thickness (T) For D≤406.4mm
T ≤ 5mm ±10%
T > 5mm ±0.50mm

T ≤ 5mm
T > 5mm

± 10%
±0.50mm
Out of roundness (O) 2% for D/T < 100, where
D/T ≥ 100 out-of-roundness

tolerance to be agreed
-  
Concavity/Convexity (independent
tolerance on outside dimensions)
- Max 0.8% with a min of 0.5mm  
Squareness of side - 90º ± 1  
External corner profile
(radius need not be tangential to the
sides) EN10219: Part 2 Table 3
- T ≤ 6.0
6.0 < T ≤10.0
1.6T to 2.4T
2.0T to 3.0T
Twist (V) - 2mm plus 0.5mm/m length  
Straightness  0.20% of total length &
3mm over any 1m length
0.15% of total length &
3mm over any 1m length
 
Mass (M) ±6% on individual
lengths
±6% on individual lengths ±6% on individual
lengths
 
Length -0 +50mm -0 +50mm -0 +50mm