Product Code EN14399-6
The force under the head of a bolt or nut can exceed, at high preloads, the compressive yield strength of the clamped material.
Hardened flat washers are designed with extra strength and can be used with Grade 8 bolts and other heat-treated fasteners
Through hardened washers are made physically stronger through carburizing or hardening, but are generally smaller in size than your standard washer.
If this occurs excessive embedding and deformation can result in bolt preload loss. To overcome this hardened washers under the bolt head can be used to distribute the force over a wider area into the clamped material.