Optimization of Restorative Heat Treatment of Turbine Housings Made from Low Alloy Steel

Abstract

Metal of steel 20KhMFL housings after restorative heat treatment with a different amount of normalizing and high-temperature tempering (1N + T, 2N + T, 3N + 2T) has been studied by experiment for the first time as applied to modernizing turbines. Data for the short-term and stress-rupture strength, ductility in tension, critical brittleness temperature, critical notch opening, and hot hardness of metal, and the amount and number of defects for repair are analyzed. The advantage of heat treatment by a regime with single-stage normalizing and high-temperature tempering (1N + T) is demonstrated.