Direct comparison
304 vs 316 Stainless: Differences and Testing
304 vs 316 stainless steel: same ASTM A240 minimum strength, different molybdenum and corrosion resistance. Sourced table and how to identify each grade.
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How do 304 (UNS S30400), 316 (UNS S31600) compare side by side?
The table below compares 304 (UNS S30400), 316 (UNS S31600) across 14 procurement-relevant dimensions, from molybdenum through source.
Side-by-side comparison
| Dimension | 304 (UNS S30400) | 316 (UNS S31600) |
|---|---|---|
| Molybdenum | None specified | 2.00-3.00% |
| Nickel | 8.0-10.5% | 10.0-14.0% |
| Chromium | 17.5-19.5% | 16.0-18.0% |
| Carbon, maximum | 0.07% (plate/sheet/strip) | 0.08% (316L: 0.030%) |
| Minimum tensile strength (ASTM A240 plate, sheet, strip) | 515 MPa (75 ksi) | 515 MPa (75 ksi); 316L: 485 MPa (70,000 psi) |
| Minimum yield strength (ASTM A240) | 205 MPa (30 ksi) | 205 MPa (30 ksi); 316L: 170 MPa (25,000 psi) |
| Minimum elongation | 40% | 40% |
| Maximum hardness | 92 HRB | 95 HRB |
| Density | 7.90 g/cm3 | 8.03 g/cm3 |
| Pitting and crevice corrosion | Reference grade: the 316 datasheet calls 316 more resistant than conventional chromium-nickel grades such as 304 | Described as more resistant to general corrosion and pitting/crevice corrosion than 304 |
| Magnet test | Austenitic, non-magnetic when annealed; can be attracted after cold work (bending, forming, drawing, rolling) | Austenitic: a magnet does not separate it from 304; annealed permeability 1.02 max |
| How to tell apart | Molybdenum spot test (a drop darkens in 2-4 minutes only if significant Mo is present), compared against known 304 and 316 samples; 304 can show a slight reaction (up to about 0.5% Mo is not unusual) | Same test; a positive result shows Mo but does not alone prove 316 (could be 316L, 2205, 904L). Certainty needs laboratory spectrometry or portable XRF/spark-emission PMI |
| When to pick each | Strength minimums are identical, so strength is not a reason to prefer 304 over 316 or the reverse | Choose where resistance to pitting and crevice corrosion is the deciding property; for chemical-service questions use the CASRAI compatibility guide |
| Source | ATI 304 and ATI 316 product pages (atimaterials.com), read 2026-10-30 | ATI 316 page; United Performance Metals 316/316L datasheet (upmet.com), read 2026-10-30; Atlas Steels Tech Note No. 1 (atlassteels.com.au), read 2026-10-30 |
Common questions
Common questions about 304 (UNS S30400) vs 316 (UNS S31600)
What is the difference in tensile strength between 304 and 316 stainless steel?
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None in the ASTM A240 minimums for plate, sheet and strip: ATI lists 515 MPa (75 ksi) minimum tensile and 205 MPa (30 ksi) minimum yield for both 304 and 316. The low-carbon 316L is lower, at 485 MPa (70,000 psi) tensile and 170 MPa (25,000 psi) yield minimum per the United Performance Metals datasheet. These are specification minimums, not typical values.
Can 304 stainless steel rust?
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Stainless steels are not rust-proof. United Performance Metals describes 316 as more resistant than conventional chromium-nickel grades such as 304 to general corrosion and to pitting and crevice corrosion, so 304 is the grade more exposed to pitting and crevice attack of the two. Service conditions decide the outcome; see the CASRAI chemical compatibility guide for chemical service.
How do I know if my stainless steel is 304 or 316?
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A magnet will not tell you, because both are austenitic and cold-worked 304 can be attracted. A molybdenum spot test, run beside known 304 and 316 samples, darkens within 2-4 minutes if significant Mo is present, but 304 can react slightly and the test cannot separate 316 from 316L. For certainty use laboratory spectrometric analysis or portable XRF/spark-emission PMI, and keep the grade, heat and batch markings. Test solutions need the safety data sheet and skin and eye protection (Atlas Steels Tech Note No. 1, read 2026-10-30).
