BFI VDEh-Betriebsforschungsinstitut GmbH

Initial situation:

• Hydrogen dissolved in steel can be interstitially embedded in the microstructure, which leads to tensile and fatigue strength reduction and therefore to component malfunctions.
• The demands on lowest hydrogen contents     in the final steel product are more and more increasing, especially for high strength steels.
• A targeted control of hydrogen content in liquid steelmaking is difficult, as the level of hydrogen pick-up after vacuum treatment can be predicted only with high uncertainty, and only spot H measurements are available.

Project targets:

• Detailed investigations on hydrogen pick-up and removal during ladle treatment and  continuous casting.
• Dedicated measurement campaigns based on novel continuous measurement technologies.
• Development of process models for monitoring and prediction of H pick-up and removal.
• Set-up of a model-based advisory system for in situ measurement and control strategies, to derive optimal operational practices. 

Innovative approaches:

• Through process modelling of hydrogen content evolution during secondary metallurgy treatment and continuous casting
• Development of new tundish lining materials with low hydrogen pickup
• Set up of a decision support system to provide practical measures to reduce the hydrogen pickup

Benefits for the industry:

• Improved steel quality with reliable achievement of lowest hydrogen contents in the final product, especially for innovative high strength steel grades. 
• Reduced energy and resource consumption due to the avoidance of vacuum treatment times longer than necessary.
• Less effort and energy consumption in post treatment process steps like annealing thermal treatment, due to a reliable adjustment of a lower hydrogen content in steel slabs, billets, blooms and ingots.
• Increased productivity in steel production