SOME EXPERIMENTS ON RESIDUAL STRESS RELIEVING

Abstract

In large forgings, such as turbine rotor, it is important operation to relief the residual stress. Therefore some experiments on stress relieving were studied by the Sachs's boring-out method. The specimens (70mm diameter, 210mm long) were quenched in water from just below Ac₁ transformation temperature, and then reheated at various temperatures and during different hours (100-600°C, 1-90h). The results obtained were as. follows;
(1) Residual stress-relieving depended mainly on the heating temperature, and the curve of stress relief showed linearity for it.
(2) Heating for long time had scarcely affected on the stress relieving.
(3) Variation of hardness at the surface of specimens by tempering showed approximately the condition of stress relieving.