ASTM F3125 Grade A490
A490 is the higher-strength structural bolt in the F3125 family. It carries tighter restrictions than A325, especially on coatings and reuse.
| Head | Heavy hex, short thread length |
|---|---|
| Marking | A490 plus maker ID. Underlined = Type 3 |
| Nut | ASTM A563 DH / DH3 (A194 2H permitted as specified) |
| Washer | ASTM F436 required |
| Coatings | No hot-dip galvanizing or electroplating. Zinc-flake per ASTM F3393 as permitted by F3125. |
Mechanical properties (F3125 Grade A490)
| Size | Proof | Yield (min) | Tensile | Hardness |
|---|---|---|---|---|
| 1/2 to 1-1/2 in | 120 ksi | 130 ksi | 150 - 173 ksi | C33 - C38 |
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
ASTM F3125 / F3125M · Grade A490 · structural bolt
What it is
FIELD IDENTIFICATION
A490 is the higher-strength structural bolt in the F3125 family. It carries tighter restrictions than A325,
especially on coatings and reuse.
MFG
A490
Heavy hex head, short thread; stamped A490 +
maker
Head
Heavy hex, short thread length
Marking
A490 plus maker ID. Underlined = Type 3
Nut
ASTM A563 DH / DH3 (A194 2H permitted as specified)
Washer
ASTM F436 required
Coatings
No hot-dip galvanizing or electroplating. Zinc-flake per ASTM F3393 as permitted by
F3125.
Mechanical properties (F3125 Grade A490)
Size
Proof
1/2 to 1-1/2 in
Yield (min)
120 ksi
Tensile
130 ksi
Hardness
150 - 173 ksi
C33 - C38
Key points
A490 bolts are not reused after full pretension.
Hardness puts A490 in the range where hydrogen embrittlement is a real risk, which is why plating is prohibited.
What it is not
Not a substitute for, or substitutable by, ASTM A354 BD, even though tensile strength is similar.
Not installed with a machinery torque chart.
Not replaceable with a class 10.9 hex bolt or SAE Grade 8.
Governing standards: ASTM F3125/F3125M-26; ASTM A563/A563M-26; ASTM F436; RCSC Specification. 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-71EBC9 · thefastenerapp.com/fastener-guide/technical-reference/astm-f3125-grade-a490 · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
