Non-destructive ultrasonic measurement of residual stress in metallic materials
| Reference number | |
| Coordinator | SWERIM AB |
| Funding from Vinnova | SEK 2 125 200 |
| Project duration | October 2022 - December 2024 |
| Status | Completed |
| Venture | The strategic innovation programme for Metallic material |
| Call | Springboard to the metallic materials of the future - Step 2 |
Important results from the project
Two ultrasonic methods were investigated to detect residual stress levels in metals: 1. Shear wave birefringence (with EMAT): A commercial electromagnetic ultrasonic probe was used in SSAB production and measured on over 2000 sheets. Despite limited statistical data, the device showed high potential to provide unique insights into the internal state of the plates. 2. Surface waves with laser ultrasound: This method successfully correlated surface residual stresses with surface wave properties.
Expected long term effects
The online residual stress measurements are expected to enable real-time monitoring and feedback to operators, which can lead to improved product quality, and with non-destructive quality control, the destructive testing can be reduced, leading to increased material yield. The laser ultrasonic measurements, which only take a few seconds, can lead to faster feedback on the manufacturing process, which is currently 10s of minutes. This means the possibility of better process control.
Approach and implementation
The project was implemented in five work packages as follows: WP1 Project coordination WP2 Experimental lab study WP3 Transient demonstrator WP4 On-line demonstrator at SSAB Oxelösund WP5 Plan for industrial implementation and dissemination of results The equipment took longer to obtain than expected, it also needed to be repaired at around halftime, which further delayed the online measurements. The collaboration between the research performers and the companies worked well.