Characterization of Hydrogen-Strain Interactions in Duplex Stainless Steel Microstructures
| Reference number | |
| Coordinator | KUNGLIGA TEKNISKA HÖGSKOLAN - Institutionen för kemi |
| Funding from Vinnova | SEK 500 000 |
| Project duration | October 2018 - October 2019 |
| Status | Completed |
| Venture | Research infrastructure - utilisation and collaboration |
| Call | Research infrastructure - utilisation and collaboration: Industrial pilot projects for neutron and photon experiments at large scale research infrastructures - 2018 |
| End-of-project report | 2018-03267_Sandvik_Materials_Technology.pdf (pdf, 312 kB) |
Purpose and goal
The main goal was to study the effect of hydrogen-strain interactions in the microstructure of duplex stainless steels utilizing synchrotron-based techniques by adapting a mini tensile tester in situ experiments. In a pilot test, the mini tensile tester was adapted for use in operando in the beamline. It was verified that the hydrogen-strain interactions were possible to characterize on microstructure level and thus enable better understanding of the mechanism of HISC, hydrogen induced stress cracking of duplex stainless steels. The work was performed by AB Sandvik Materials Technology in collaboration with KTH.
Expected results and effects
An experimental method with an in-situ cell for the beam line have been investigated. Obtained results indicates that the developed method is promising to investigate microstructures influence on hydrogen degradation. The results have shown that hydrogen leads to the evolution of tensile strains in the microstructure. More strains were developed in the austenite phase than the ferrite phase during hydrogen charging. The collaboration has further enabled the access to large-scale synchrotron facilities which will be used for further experiments with the developed method.
Planned approach and implementation
The effect of hydrogen uptake in the microstructure of super duplex stainless steel with varying coarseness in the microstructure were studied by using synchrotron based techniques. This was performed in-situ and in-operando. High-energy x-ray diffraction measurements were carried out at the Swedish beamline P21.2 at DESY in Hamburg. The specimens were strained and cathodically polarised, immersed in sodium chloride solution during the experiments. Both local hydrogen uptake and local strains in the ferrite and austenite phases were analyzed.