Metal
Stainless 304
The general purpose stainless. Corrosion resistant, hygienic, and formable.
Published values for unfilled grades at 23 °C unless stated. Confirm against the supplier datasheet for the grade you specify.
What it is
304 is an austenitic chromium-nickel stainless and the most used stainless grade worldwide. The chromium forms a passive oxide film that reforms if scratched, which is what gives the alloy its corrosion resistance.
It is very ductile, deep draws well, and welds without special procedure. It also work hardens aggressively, which makes machining slow and expensive compared with aluminum.
Where it is used
- Food, beverage, and pharmaceutical equipment
- Medical and laboratory hardware
- Architectural panels and fixings
- Sheet metal enclosures for washdown environments
- Fluid handling components
Processing notes
Machine with sharp tools, heavy feed, and constant engagement. Dwelling in the cut work hardens the surface and destroys the next pass.
Welds readily; use low-carbon 304L for welded assemblies to avoid carbide precipitation at the heat-affected zone.
Passivate after machining or welding to restore the oxide layer.
Available through
Design notes
Expect machining to cost several times the equivalent aluminum part. Specify stainless where the environment requires it, not by default.
Minimum bend radius roughly 1.0 × thickness; springback is significant and needs tool compensation.
Avoid crevices and lap joints in wet environments; crevice corrosion is the usual failure mode, not general rusting.
Grades and variants
- 304, the general purpose grade
- 304L, low carbon, for welded assemblies
- 303, free machining with added sulphur, poorer corrosion resistance
- 316 / 316L, molybdenum added, much better chloride resistance
- 2205 duplex, higher strength and chloride resistance
Alternatives
If Stainless 304 is not the right answer
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