As shown in Illustration 5.2, the extrusion limit of o-rings under pressure is determined by the size of the diametrical clearance gap and the hardness of the o-ring material.

If the point representing the intersection of the lines of sealed pressure and diametrical clearance falls to the right of the material's hardness curve, either the material hardness must be increased, or back-up rings will be required.


Illustration 5.2 (Extrusion Limit)

Extrusion Limit