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Design Basics | Standards Update | AS/NZS 4680: 2006 Specification | Galvanized Reinforcement | Design Specification and Inspection | Bolting | Welding
Design Basics for Galvanizing
Here are some of the basic rules which should be used in design and fabrication.
- You can galvanize all mild steels, some low alloy steels, cast iron and cast steel.
- You can galvanize a wide variety of shapes and sizes and weights.
But consult your galvanizer if you have an unusual shape.
- Follow the design guidance about vent holes in hollow sections
- Provide an additional clearance equal to 4x the coating thickness
on threaded fasteners.
- Provide about 1mm extra clearance on all matting surfaces
- Do not attempt to galvanize low melting point soldered joints. They
will collapse.
- Do not use silicon – containing anti splatter paints. The
galvanizing will not “take” on these paints.
- Remove moulding sand from castings by grit blasting. Galvanizing
will not “take” to sand.
- Avoid overlapping surfaces if possible. If you cannot avoid them,
make sure you follow the venting guidance.
- Remember the galvanizer must lift and turn your fabrication. Make
sure you provide lifting points for him to use.
- Do not ask your galvanizer to galvanize fabrications which are very
stiff in one plane but not in another. They will almost certainly distort.
- Avoid large unsupported areas of this gauge sheet. They will probably
distort.
The galvanizing reaction between zinc and steel takes place in liquid zinc, usually
at 445 - 460 deg. C. At this temperature iron and zinc react
quickly. Typically the steel may be in the zinc for only a
few minutes. The fabrication is taken out of the zinc when
the reaction is complete. Although the zinc coating has already
formed, it's internal structure continues to change until
the steel returns to normal temperature.
If in doubt
Most galvanizers have seen your problem before. If you have any doubts about
designing for galvanizing, talk to your galvanizer. He can almost certainly help.
A list of leading Australian galvanizers is in our members directory.
If you prefer you can also talk to the technical staff at the Galvanizers
Association of Australia. If we cannot assist immediately we have access to
all other technical expertise throughout the world.
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