Effect of heat treatment modes on structure and properties of 08Kh18N6AG10S steel

The paper studies the influence of heat treatment modes on the structure and properties of austenitic steel grade 08Kh18N6AG10S. Austeni­tic structure with twinned boundaries was preserved after quenching at 1040 and 1100 ℃. At the same time, the average size of austenitic grains decreased from 42.3 ± 6 μm (supply condition) to 38.1 ± 5.0 and 39.0 ± 4.5 μm, respectively. Quenching at 1040 ℃ leads to release of excess carbide phases at the grain boundaries. Mainly manganese and silicon oxides were found after quenching at 1100 ℃. Quenching at 1040 ℃ leads to a slight decrease in microhardness (by 12 %) compared to the condition of supply (from 3285 ± 80 to 2895 ± 70 MPa). The hardness decreases less after quenching at 1100 ℃ (up to 3090 ± 80 MPa). Quenching at 1040 and 1100 ℃ has significantly improved the fracture toughness of steel. Values of impact strength of the steel increased to 223 ± 10 and 240 ± 5 J/cm 2 compared to the condition of supply (55 J/cm 2 ). The authors found that the steel samples demonstrate a comparable level of wear resistance during tests for abrasive wear compared to the condition of supply after quenching at 1040 and 1100 ℃. The mass loss after passing the roller distance of 4309 m for all steel conditions is approximately 8.0 %. The authors concluded that the most optimal heat treatment of 08Kh18N6AG10S steel is quenching at 1100 ℃, which improves the fracture toughness of steel while maintaining microhardness and wear resistance.