Standardisation of industrial residual stress characterisation: EASI-STRESS

The electron storage ring of the ESRF in Grenoble, one of the most powerful synchrotrons in Europe. Foto: ESRF

There have always been various ways of working metals. For example, they can be forged, welded, cast or additively manufactured. In all these processes, residual stresses are generated in the material. But: Residual stresses in metals may lead to catastrophic failures under fatigue processes. Therefore, they are of key importance across all industrial sectors where metals are used, e.g. within the transportation and energy sectors. Such residual stresses are investigated using various methods. These include neutrons and synchrotron X-rays. They penetrate into metals and alloys and enable non-destructive direct determination of bulk stresses.

Insufficient comparability

In the EU project EASI-STRESS, characterizations of residual stress of materials are to be standardized and optimized. Graphic: EASI-STRESS

In the past, industrial developers have struggled to utilise synchrotron x-ray and neutron diffraction-based residual stress characterisation tools due to insufficient data comparability and lack of harmonised protocols. This made it difficult to confirm reproducibility and traceability of the measurements. “We aim at lowering these barriers for industry by setting up European-wide standards and operating procedures and harmonising data formats,” explains project coordinator Dr. Nikolaj Zangenberg.

The EASI-STRESS project wants to support companies in analysing and improving their materials in the best possible way. With the help of the measurements, the industry can better predict and control stresses in materials and thus optimize the design of components. It is also sustainable: those who know their materials well can reduce material consumption or shorten time to market by qualifying new materials or processes more quickly.

First experiments started

During November, the project partners will conduct experiments from performed residual stress measurements on new developed round robin samples. The samples are measured at several neutron and synchrotron instruments, relevant standardised laboratory techniques. The results will be compared to modelling data. The samples are designed to replicate different industrial processed that will, at a later stage in the project, also be investigated in real industrial components through case studies defined by the industrial partners.