Corrosion-resistant steels EI961-Sh (TU 14-1-1239–75), EP479-Sh (TU 14-1-1434–75) and high-speed steel R18 were quenched in vacuum furnaces with cooling in a medium of circulating inert gas (argon) at a pressure of 0.6 105, 105, 5.5 105 Pa. For comparison, the properties of steels EI961-Sh and EP479-Sh were studied after heat treatment in chamber furnaces with an oxidizing medium. The tested specimens of steels EI961-Sh and EP479-Sh were 10, 30, and 50 mm in diameter; the specimens of highspeed steel R18 were 6, 8, 10, and 14 mm in diameter. In order to simulate full charging, the specimens were charged into the furnace together with ballast pieces with the corresponding cross section. The heat treatment regimes are presented in Table 1. In order to estimate the cooling rate in quenching, the control thermocouple was calked in the center of the specimens with maximum cross section. The cooling rate was calculated from the diagram of the control thermocouple in the temperature range of carbide segregation (1000 – 500°C) for steels EI961-Sh, EP479-Sh and at 1000 – 550°C for steel R18. The quality of the treatment was estimated in terms of the mechanical properties r , 0.2 , , , KCU, the HRCe hardness, and the microstructure; fracture surfaces of impact specimens were examined visually.