Portable X-ray Analyzer of Internal Stresses and Residual Austenite
Once in the 1980s, I worked with ing. M. Čermák from SVÚM Prague and ing. Jirka Sikač from SVÚOM Prague on the development of thin films of TiN. Mr. Ing. Čermák did all the X-ray analyses for us both for plasma nitriding and later for deposition processes. And not only the phase composition, but above all the tension in the layers. At that time, it was Jirka Sikač in the neighboring house who helped develop a method to accurately measure the stress in the TiN layer. An X-ray was made on the sample with a layer, which was then separated in hydrogen peroxide. Since the layer/substrate interface was preferentially etched, TiN powder remained, which represented zero residual stress. The spectral lines were compared and the stress was then calculated from the line shift.
Since then, I have known that the macroscopic stress in the steel surface can be determined from the displacement of the diffraction lines, and the microscopic stress can be determined from the expansion of the diffraction lines. However, it is also possible to reliably determine residual austenite from X-ray analysis.
However, my ideas were always connected with the device that we still had in VVZ Liberec ZEZ Praha, in Chrastavská Street. It was certainly non-transferable.
Recently, however, I have received a lot of assignments on the topic of internal stresses in the steel surface, both during thermal fatigue and during welding or after 3D printing. And so I was looking for help with it or what to recommend.
I discovered a device from Pulstec Industrial Co., Ltd. from Japan, which really excited me. It weighs 3 kg, is portable, and can do X-ray analysis anywhere because it runs on batteries. Thus, it can be used both in the laboratory and in operation. Its trade name is μ-X360. Measurement time? 40 seconds.
A presentation of the method and the device can be found in this video here:
and a link to the company’s website here:
https://www.pulstec.co.jp/en/product/x-ray/
Because I have enough fantasy, I can imagine a number of applications on how and where to use it. For example, in the case of die-casting dies, it would be possible to periodically measure the stress in the surface in the foundry, and when the limit value is reached, intermediate stress annealing could be included. Another use is for large weldments, where we do not have the possibility of a thermal annealing process, but we want to know whether the strength properties of steel will be exceeded in terms of future use. In combination with vibration annealing, it seems almost genius to me. Similarly, when examining residual austenite, in this case there will be no need for samples, we can do it right on the real piece. Utopia or chimera?
For me, it’s a challenge.
Jiří Stanislav
October 27, 2025
