Development and Production of Weldable High-Strength Steels with a Yield Point in the Range from 600 to 950 N/mm2

Studies have been made of the microstructure of steel 18KhGNMFR after the quenching and tempering and “ normalizing rolling” of plates 12 and 22 mm thick. Raising the quenching temperature to 950°C leads to growth of the austenite grains, which reduces impact toughness. Thus, the quenching temperature for steel 18KhGNMFR should be no greater than 920°C. On the whole, the structure of the steel in 9–14-mm-thick plates subjected to normalizing rolling is uniform and is free of grain-boundary precipitates of carbide particles. This ensures that the steel will have satisfactory toughness properties.