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- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
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- MERKBLATT AD 2000 W2/W7/W10
Is F436 the Same as Grade 8? — F436 vs Grade 8 Explained
No. ASTM F436 is a washer specification; Grade 8 is a bolt grade. The confusion is common because high-strength bolts (SAE J429 Grade 8) and hardened washers (ASTM F436) are often specified together in the same structural connection — but they cover different components, issued by different bodies, and tested against different requirements.
What ASTM F436 Covers
ASTM F436/F436M is the standard for hardened steel washers. It defines material grades (Type 1 carbon steel, Type 3 weathering steel), hardness range (HRC 38–45 through-hardened), chemical limits, dimensional tolerances and marking. F436 covers inch series washers (1/4 in. through 4 in.); F436M covers metric (M12 through M100). No bolt grade is implied by F436.
What SAE Grade 8 Covers
SAE J429 Grade 8 is a designation for high-strength carbon-alloy steel bolts, screws and studs. Grade 8 bolts are heat-treated to a minimum tensile strength of 150 ksi and identified by six radial line marks on the bolt head. The grade applies only to externally threaded fasteners — there is no SAE Grade 8 washer in the SAE standard. Grade 8 is roughly equivalent to ISO Property Class 10.9 and is similar in strength range to ASTM A325 / A490 structural bolts.
F436 vs Grade 8 at a Glance
| Attribute | ASTM F436 | SAE J429 Grade 8 |
|---|---|---|
| Component type | Washer | Bolt, screw, stud |
| Issuing body | ASTM International | SAE International |
| Hardness | HRC 38–45 through-hardened | HRC 33–39 (typical) |
| Tensile | Not applicable (washer) | 150 ksi min |
| Marking | "TB F436 1" or "TB F436 3" | 6 radial lines on bolt head |
| Common pairing | Grade 8 bolts, A325, A490, F3125 | F436 hardened washers |
Pairing F436 Washers with Grade 8 Bolts
When a Grade 8 hex-head bolt is pre-loaded near yield, the bolt head exerts very high bearing stress on whatever sits beneath it. A plain unhardened washer (F844 or SAE plain) would embed into the joint surface and lose preload. F436 Type 1 washers (HRC 38–45) resist embedment and maintain the engineered preload. For automotive, off-road equipment, agricultural machinery and structural joints using Grade 8 bolts, F436 Type 1 is the standard washer choice. For exposed weathering-steel applications use F436 Type 3 with Grade 8 or A325 Type 3 bolts.
See Also
F436 washer specifications · F436 washer dimensions · F436 vs F844 · F436 vs SAE.
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