Laser ultrasonics for real-time monitoring of microstructures for efficient development and manufacturing of high performance steel

Malmström, Mikael; Swerea KIMAB AB; Sweden

Malmström, M.; Swerea-KIMAB; Sweden
Lindh-Ulmgren, E.; Swerea-KIMAB ; Sweden
Martin, D.; Swerea-KIMAB ; Sweden
Huchinson, B.; Swerea-KIMAB ; Sweden
Åslund, M.; Swerea-KIMAB ; Sweden
Mauritzon, L.; Swerea-KIMAB ; Sweden
Sollander, H.; SSAB EMEA AB; Sweden
Mousavi, S.; SSAB EMEA AB; Sweden
Moosavi, E.; Sandvik Materials Technology; Sweden
Sandström, M.; Sandvik Materials Technology; Sweden
Siriki, R.; Sandvik Materials Technology; Sweden
Bergman, A.; Sandvik Materials Technology; Sweden

ID: ECNDT-0522-2018
Download: PDF
Session: Acoustic Emission 2 / Laser UT 1
Room: J1
Date: 2018-06-14
Time: 10:00 - 10:20

The hot strip rolling mill used in the steel industry is a highly automated system that is capable of producing hundreds of km rolled of strip daily. Many of the process parameters, e.g., temperature, sheet velocity, deformation conditions etc., are used to control this process. However, there are still critical material related parameters, including grain-size, texture and austenite/ferrite phase fraction that still require expensive and time consuming destructive testing after rolling to be measured. These measured product features cannot easily be used in process control because of the time between processing and measurement can extend to several days after manufacturing. Laser ultrasonics (LUS) is a non-destructive method that has capability of being operated in-line and integrated directly into process control systems. Features of the LUS signal have shown correlation to these material parameters. The Swedish steel project REMOMIC PLUS aims to implement laser ultrasonics in-line in a steel strip mill as an online non-contact method for microstructure characterization during the hot rolling (<1200 °C) of high strength steel. This work summarizes some of the results of the project. Prior to the in-line installation of the LUS system at SSAB in Borlänge, the technology has been evaluated in a small test mill at Sandvik Materials Technology in Sandviken. Results from the mill trials as well as themo-mechanical simulations of hot rolling in a Gleeble with a LUS ad-on performed at Swerea KIMAB in Stockholm will be presented.