1. Isothermal annealing of 85KhF (85Kh) and ShKh15 steels to a hardness of HRC 48-55 increases the toughness almost twice (by comparison with quenching and tempering to the same hardness). 2. With isothermal annealing the hardness of 85KhF and ShKh15 steels (links of saw chains, for example) can be increased by 5–6 HRC units without lowering the toughness. 3. Isothermal annealing increases the wear resistance of saw chains 50% by comparison with quenching in oil and tempering to the same hardness. 4. isothermally annealed saw chains with a hardness of HRC 52-57 (4 HRC units higher than for ordinary chains) have a wear resistance 2 times higher than that of saw chains quenched in oil and tempered to the hardness specified for the actual working conditions.