Provision of the Quality of Manufacturing Gear Wheels in Energy Engineering

Abstract

Mathematical modeling of thermal processes during grinding and of the process of formation of residual stresses and cracks is done. On this basis the technique of calculation of thermal processes and of internal residual stresses arising during grinding of wheels made of cemented steels is offered. It is shown that the grinding temperature when machining gears from cemented steels should not exceed the temperature at which the reverse martensitic transformation occurs-the formation of austenite. The formed austenite during grinding does not completely turn into martensite, since the cooling temperature does not overlap the interval Ms-Mf as a result the so-called burnings of hardening are formed. Burnings of hardening 3–4 times reduce the strength and durability of the ground surface, and therefore of the whole part. On the basis of performed calculations, ways of improving the quality of manufacturing of work surfaces of teeth of tooth gears, which are used in aggregates of thermal and nuclear power plants, are proposed and substantiated.