Two sets of strain-hardening flow laws based on an analogy with a kinematic model are derived for circular plates made of an initially Tresca material. The two sets of flow laws, called complete and direct hardening, differ in the point at which the plane-stress assumption is introduced. The complete-hardening flow laws are more consistent since the plane-stress assumption is made at the latest possible stage in their derivation. Complete and direct-hardening solutions are obtained to each of three different plate problems. The results indicate that the direct-hardening solutions give a fair approximation to the complete-hardening ones.