Guide · Finishes
Pre-Galvanised vs Hot-Dip Galvanised Steel
Both finishes give a zinc coating — but the process, thickness and where you use them are different. A quick guide for fencing contractors and fabricators.
Specification & Supply
Pre-galvanised steel (sometimes called in-line galvanised) is zinc-coated during the tube rolling process — the strip is galvanised before being formed into RHS, SHS or CHS. Hot-dip galvanised (HDG) steel is fully immersed in molten zinc after fabrication to AS/NZS 4680, giving a much thicker coating including inside the section and across welds and cut ends. As a rule: pre-galv is cost-effective for sheltered or non-aggressive sites; HDG-after-fabrication is the go-to for coastal, industrial, civil and long-life applications.
- Pre-galv: zinc applied to strip before tube forming
- HDG: full immersion after fabrication to AS/NZS 4680
- HDG coats inside the section, welds and cut ends
- HDG coating typically 600 g/m² (~85 µm) — much thicker than pre-galv
- Use HDG for coastal, industrial, civil and engineered jobs
- Use pre-galv for cost-effective fencing in sheltered conditions
Specifications
AS/NZS 4680| Pre-Galvanised — Coating | Typical Z275 / Z350 (~20 µm) — strip galvanised before forming |
|---|---|
| HDG (AS/NZS 4680) — Coating | Typical 600 g/m² (~85 µm) — full immersion after fabrication |
| Cut Ends & Welds | Pre-galv: zinc-rich touch-up needed. HDG: coated as part of dipping. |
| Internal Coating | Pre-galv: limited. HDG: fully coated inside and out. |
| Service Life (general guide) | Pre-galv suits sheltered duty · HDG suits coastal, industrial, civil long-life |
| Cost | Pre-galv lower base cost · HDG higher upfront, lower lifetime cost |
| Standards | Pre-galv steel to AS/NZS 1163 · HDG coating to AS/NZS 4680 |
Why contractors buy steel from us
Trade WholesaleMill direct supply
Sourced direct from Australian and approved overseas mills — bulk pricing without the merchant markup.
AS/NZS compliant
Steel manufactured to recognised Australian Standards. Mill certificates supplied on request for engineered jobs.
Cut to length
Mill lengths, standard fencing lengths or cut-to-size packs — palletised ready for site.
Australia-wide freight
Direct truck loads, part loads and palletised freight to metro, regional and remote project sites.
Bulk & project quantities
From single pack to full mill order — priced for fencing contractors, fabricators and infrastructure programs.
Trade-only pricing
We supply the trade — fencing contractors, fabricators, steel merchants, landscapers and government buyers.