“…The results of theoretical and experimental studies point out [1,2] that it isn't possible to estimate durability of machine parts, subjected to cyclic loadings in service, relying on mechanical properties of a material: proportionality limit ( пц σ ), elastic limit ( y σ ), yield strength ( T σ ), tensile strength ( B σ ), obtained when tensile testing of specimens. Determination of machine parts durability when cyclic deforming required plotting curves of fatigue or Wohler's curves [3,4].…”