Study on Industrial Use of X-Ray Stress Measurement

Abstract

Generally, the results of X-ray stress measurement are influenced by surface conditions and material conditions. So two series of experiments have been carried out by the anothors using X-ray diffraction method with twin pole geiger-muller counter. First, the effects of surface conditions on the measured results have been studied to obtain the data on surface treating procedures. Then the reliability of measured values has been investigated for several heat treated materials to secure the possibility of industrial use of X-ray stress measurement. The results of above experiments are as follows.(1) It is important to flatten the specimen surface and to remove the plastically deformed layer that occurred due to the surface treatments, before the stress measurements was made by X-rays. It has been shown that the surface should not be more than JIS6S (as mild steel polished by emery paper #60∼100) in roughness, and that the plastically deformed layers due respectively to polishing by emery paper (#320∼#100), to grinding by portable grinder, and to machining by shaping machines, have depth of 30∼40μ, 140∼170μ and 60∼100μ accordingly.(2) Various heat treated materials including mild steel, 1Cr-1/2Mo steel and 21/4Cr-1Mo steel have been tested, and the effect of the profiles of X-ray diffraction pattern on the measured results has been investigated. It has been shown that the measured results become unreliable when the profiles of diffraction patterns become spotty, although the scatter of the measured results is small in the case of good profiles of diffraction patterns. And it has been found that the measured values of stresses become considerably reliable, even if the case of Kα doublets are in distinguishable, when the wider receiving slits are used.