Abstract
The X-ray stress measurement using a diffractometer specially designed for the purpose has recently been prevailing. Little or no experiment on X-ray stress measurement, however, has so far been made by means of an ordinary diffractometer.
In this paper, the possibility of residual stress measurement by means of sin2ψ-method using a single pole counter diffractometer, Shimadzu GX-2, is discussed. In measuring the residual stress using this type of a diffractometer, the following two conditions must be fulfilled. One is that the specimen can be fixed at an arbitrary angle position, only the counter being made to scan. The other is that the counter can be shifted precisely in the radial direction of the goniometer with a change in ψ. The errors which may arise from this shift of the counter and from mis-setting of the specimen are estimated.
Next, the results obtained from the experiments are reported, which were carried out on extended α- and (α+β)-brass specimens in order to confirm the so called surface effect, the reflecting plane dependence of residual stress values, and the“Gefügespannungen”which had been observed by many investigaters. The plate specimens were annealed at 550°C for 2hrs in an argon atmospher and were extended 3% statically. The thin layers were successively removed from both sides of the specimen. The residual stresses in α-brass and those in both α- and β-phases of (α+β)-brass on each layer near the specimen surface were determined by means of sin2ψ-method. The reflecting planes used were (420), (331), (400) and (311) planes of α-phase in α- and (α+β)-brasses, and (321) and (211) planes of β-phase in (α+β)-brass, respectively.
The results are as follows
(a) After the extension of 3%, the residual stress in α-brass specimen is compression on the surface, showing a tendency to change into tension in the interior of specimen. The reflecting plane dependence of residual stress values is found out on each layer. However, the stress distribution in the cross-section of specimen shows the similar aspect for each lattice plane used.
(b) After the extension of (α+β)-brass specimen by 3%, α-phase remains in compression, while β-phase in tension. The reflecting plane dependence of residual stress values and the surface effect are observed as in α-brass specimen.
