抄録
In the previous paper, the value of constant KX(-34.10±1.7kg/mm2/deg) needed for the X-ray stress measurement of 18 Cr-8 Ni austenitic stainless steel was determined with high accuracy from γ(311) diffraction of CrKβ radiation by the ψ0 oscillation method. However, the study on stainless steel which has been subjected to severe plastic deformation has not been made so far. In this study, the X-ray elastic constants of tensile pre-strained 18-8 stainless steels were measured by the ψ0 oscillation method with CrKβ γ(311) diffraction, and by the η oscillation method with CrKα γ(220) diffraction, and the accuracy of the measurement was examined.
The results are summarized as follows.
(1) From a viewpoint of accuracy, it is desirable to apply the ψ0 oscillation method for γ(311) diffraction of CrKβ radiation and the η oscillation method for the CrKα γ(220).
(2) In the CrKβ γ(311) ψ0 oscillation method, the absolute value of the constant KX increases slightly with pre-strain in the range of small pre-strain but it reaches a certain saturated value when pre-strain becomes large. In the CrKα γ(220) η oscillation method, it decreases gradually with increasing pre-strain. The latter results can be qualitatively explained by taking the tensile deformation texture into analysis, though in the former case a clear explanation has not been made.
(3) For the X-ray stress measurements of some unknown pre-strained stainless steels of which the diffraction intensity curve from CrKβ γ(311) diffraction is known to be practically uninfluenced by CrKα α(211) diffraction, the K-value for 18-8 stainless steel reported previously (KX=-34.10 kg/mm2/deg) is considered appropriate in practical use, and the error of measurement is at most 10per cent.
