316 Stainless Fasteners
316 adds 2 - 3% molybdenum to the 18-8 base. That improves resistance to chlorides and pitting, which is why it is the standard marine and coastal stainless.
Chemistry (typical)
| Alloy | Chromium | Nickel | Molybdenum | Best for |
|---|---|---|---|---|
| 304 | 18 - 20% | 8 - 10.5% | - | General corrosion resistance |
| 316 | 16 - 18% | 10 - 14% | 2 - 3% | Chlorides, marine, chemical |
Strength by specification
| Specification | Class / condition | Tensile (min) |
|---|---|---|
| ASTM F593 Group 2 | CW1, 1/4 - 5/8 in | 100 ksi |
| ASTM F593 Group 2 | CW2, 3/4 - 1-1/2 in | 85 ksi |
| ISO 3506 | A4-70 / A4-80 | 700 / 800 MPa |
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
Alloy 316 · austenitic stainless · molybdenum grade
What it is
FIELD IDENTIFICATION
316 adds 2 - 3% molybdenum to the 18-8 base. That improves resistance to chlorides and pitting,
which is why it is the standard marine and coastal stainless.
MFG
316*
Alloy/condition marking varies
Chemistry (typical)
Alloy
Chromium
Nickel
Molybdenum
Best for
304
18 - 20%
8 - 10.5%
-
General corrosion resistance
316
16 - 18%
10 - 14%
2 - 3%
Chlorides, marine, chemical
Strength by specification
Specification
Class / condition
Tensile (min)
ASTM F593 Group 2
CW1, 1/4 - 5/8 in
100 ksi
ASTM F593 Group 2
CW2, 3/4 - 1-1/2 in
85 ksi
A4-70 / A4-80
700 / 800 MPa
ISO 3506
Key points
316 still suffers crevice corrosion in stagnant salt water. Design for drainage and oxygen access.
Keep 316 fasteners away from carbon steel and aluminum without isolation.
Governing standards: ASTM F593-24; ASTM F594-24 (nuts); ISO 3506-1/-2:2020. Editions shown are the latest confirmed as of September 2026. The drawing and the governing
standard always take precedence over this sheet.
torquing any fastener. Verify the current governing standard, project documents, OEM requirements, size, thread, coating and lot certification. To the fullest extent permitted by law, The Fastener App disclaims liability
arising from reliance on this reference.
Fastener Guide reference FG-938F6B · thefastenerapp.com/fastener-guide/technical-reference/316-stainless-fasteners · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
