Prevent distortion

Bolted and welded assemblies varying in thickness can cause deformities or distorsion. This is caused by the variations in heating and cooling of the pieces. It is recommended to galvanize these structures prior to assembly. Assembly can then be completed by welding and reconditioning or by means of bolting or riveting with pre-galvanized hardware. Distortion can also occur during the release of welding stresses in the kettle. Therefore, proceed with welding within guidelines to balance out these stresses.

Reasons for distortion

Distortion is almost always attributable to:

• Release of existing or created stresses in the steel (welding, laminating, forming); • Expansion constraints for assemblies of varying thicknesses when galvanizing; • Assemblies requiring different immersion speeds.

This can be avoided by:

• Design symmetry and proper sequencing of assembly; • A design that allows for quick immersion and withdrawal in the zinc kettle.

In thin-wall applications, when possible, use reinforcements that are omega or diamondshaped. When in doubt, request advice from your galvanizer

Folding of plate will introduce a certain amount of strentgh and reduce the possibility of distortion

Large sheets can be break pressed which will reduce the distortion to smaller areas. Twisting may occure even though the measures have been taken