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Grade 8 Thru-Hardened Plain Steel SAE Flat Washers

What are Grade 8 thru-hardened plain steel SAE washers? Grade 8 thru-hardened plain steel SAE flat washers are high-strength, heat-treated compact-pattern washers with no plating. The thru-hardening lets them resist the concentrated load of Grade 8 bolts without deforming, while the SAE pattern gives a tight fit for automotive and machinery in coated or interior assemblies.

When to use plain thru-hardened washers

Plain steel thru-hardened SAE 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 compact SAE pattern fits tight clearances. 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 SAE washers

  • High strength: thru-hardened to resist deformation under Grade 8 bolts.
  • Preserves preload: will not dish and lose clamping force.
  • Compact fit: SAE pattern suits tight clearances.
  • Bare finish: for coated assemblies or where plating is not needed.

Common applications for Grade 8 thru-hardened plain SAE washers

  • Grade 8 high-strength bolted joints
  • Assemblies coated or painted after build
  • Automotive and machinery in tight clearances
  • Interior high-load connections

For a corrosion-resistant finish, see Grade 8 thru-hardened yellow zinc SAE flat washers, and browse every option on the main flat washers category.

Grade 8 Thru-Hardened Plain Steel SAE 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 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.