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Choosing between SUS304 and SUS316L for machined parts
The choice is a corrosion-environment decision with a machining cost attached, not a general quality decision.
SUS304 is the default austenitic stainless: good corrosion resistance in most environments, widely available, and the cheaper of the two to buy and to cut. For the majority of machined hardware it is the correct answer.
SUS316L adds molybdenum, which substantially improves resistance to chlorides. That matters in marine environments, in some medical and food applications, and anywhere the part sees salt. It is more expensive and tougher on tooling, so it costs more per part for reasons beyond the material price.
Specifying 316L 'to be safe' when 304 would do is a common and expensive habit. Specifying 304 where chlorides are present is the opposite error and shows up as pitting months after delivery. If you are unsure which environment applies, tell us what the part sits in and we will say which we would use.
Specifications
| SUS304 | Default choice, cheaper to buy and to machine |
|---|---|
| SUS316L | Chloride resistance for marine, medical and food work |
| Tell us | The environment, and we will recommend the grade |
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