Choice of tempering mode for relieving stresses in parts

The computational method for designing tempering modes for relaxing residual stresses is based on the data of creep tests of the steel. As applied to the tempering mode we should possess results of determination of the creep resistance of the alloys in the first and second stages. It is known that testing of metallic materials for stress relaxation with the use of rings of equal bending resistance (due to I. A. Oding) does not make it possible to determine their resistance to short-term relaxation. The use of devices like Rel 5 is virtually impossible due to the scarceness of such testing machines in the Russian Federation. Solution of the problem by computation with the use of Norton’s formula, which characterizes the dependence of the minimum creep rate (rate of creep in the steady stage) on the stress [1], i.e.,