Related Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
F436 vs F844 Washer — What is the Difference?
ASTM F436 covers hardened steel washers; ASTM F844 covers plain (unhardened) steel washers. The two specifications share many of the same outline shapes (circular, oversize, etc.) but differ on hardness, dimensional tolerance and intended application. F436 is required in structural-bolting joints where preload must be controlled and bolt heads cannot embed into the washer face. F844 is used for general purpose load spreading where the joint is non-structural.
Key Differences at a Glance
| Attribute | ASTM F436 | ASTM F844 |
|---|---|---|
| Material state | Hardened (heat-treated or carburized) | Plain (unhardened) |
| Hardness requirement | HRC 38–45 through-hardened | None specified |
| Typical use | Structural bolting with A325, A490, F3125 | General-purpose load spreading |
| Grades | Type 1 (carbon), Type 3 (weathering) | Plain steel only |
| Coatings | Hot-dip galv, mech galv, Geomet, Xylan | Plain or zinc-plated |
| Bevel/clipped forms | Yes — per F436 | No formal beveled/clipped variant in F844 |
| Marking | "TB F436 1" or "TB F436 3" | Not marked |
When to Specify F436 Over F844
Specify F436 wherever the connection is structural — that is, where the bolt preload is set by torque or tension and where embedment of the washer under the bolt head would compromise joint performance. F844 is appropriate for non-structural fastening such as mounting brackets, sheet-metal assemblies, and machinery joints that are not preload-critical. RCSC (Research Council on Structural Connections) specifications for high-strength bolt assemblies call for F436 hardened washers; SAE J429 grade 5 / grade 8 bolts paired with F844 plain washers would not meet RCSC.
See Also
Detailed F436 data: F436 specifications, F436 dimensions, Type 1 carbon steel, Type 3 weathering steel. Related comparisons: F436 vs SAE washer, F436 vs Grade 8.
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