Grade 8 Thru-Hardened Plain Steel USS Flat Washers
What are Grade 8 thru-hardened plain steel USS washers? Grade 8 thru-hardened plain steel USS flat washers are high-strength, heat-treated wide-pattern washers with no plating. The thru-hardening lets them resist the concentrated load of Grade 8 bolts without deforming, while the wide USS pattern spreads that load over a broad surface, making them a standard for high-strength joints.
When to use plain thru-hardened washers
Plain steel thru-hardened USS washers give the same high-strength, deformation-resistant performance as the yellow zinc version, without a plated finish. They are chosen where corrosion is not a concern, where the assembly will be coated or painted afterward, or where a bare finish is specified. The thru-hardening resists dishing under Grade 8 bolts, and the wide USS pattern spreads the load. Because plain steel can rust in damp conditions, protect the assembly or choose a plated version for outdoor and wet use. Always pair a Grade 8 washer with Grade 8 bolts.
Why choose Grade 8 thru-hardened plain steel USS washers
- High strength: thru-hardened to resist deformation under Grade 8 bolts.
- Preserves preload: will not dish and lose clamping force.
- Wide bearing: USS pattern spreads load over a broad surface.
- Bare finish: for coated assemblies or where plating is not needed.
Common applications for Grade 8 thru-hardened plain USS washers
- Grade 8 high-strength bolted joints
- Assemblies coated or painted after build
- Heavy machinery and structural work
- Interior high-load connections
For a corrosion-resistant finish, see Grade 8 thru-hardened yellow zinc USS flat washers, and browse every option on the main flat washers category.
Grade 8 Thru-Hardened Plain Steel USS Washers FAQ
What does thru-hardened mean?
The washer is heat-treated all the way through, not just on the surface, so it resists deformation under the high clamping load of Grade 8 bolts.
Are plain steel washers good outdoors?
No. Plain steel can rust in damp conditions. Protect or coat the assembly, or choose a yellow zinc or galvanized version for outdoor use.
Why choose plain over plated?
Plain steel suits assemblies that will be coated or painted afterward, or where a bare finish is specified and corrosion is not a concern.