1. It was established that in the process of deformation the e phase may transform to γ phase not only at temperatures where the e→γ transformation occurs during heating but also at lower temperatures. 2. The formation of γ phase is martensitic in character. The transformation of e phase into γ phase is possible when the accumulation of hep stacking faults reaches a certain level. 3. The reversibility of the γ⇌e transformations during deformation was established. 4. The mechanical properties of high-manganese alloy G22 depend on the e⇌γ transformation that oceurs under load, since plastic deformation may result from the latter. As in the direct γ⇌e and γ⇌α transformations, this transformation facilitates relaxation processes.