Laser-based process monitors quality and temperature of molten steel

20 Jun 2018

University of Swansea wins UK prize for technology that could save steel plants millions of pounds.

A technique that could allow better monitoring of the temperature and composition of molten steel, both key parameters for the successful manufacture of a final item, has won the 2018 Materials Science Venture Prize from the Armourers and Brasiers Company.

Developed by Szymon Kubal and a team at the University of Swansea, the technique is said to involve lasers projected into the molten furnace in order to monitor the contents continually, without the need for disposable probes or for production to be halted.

"Our new technology allows a laser beam to be projected into a molten furnace through a channel called a tuyère in the furnace wall, exploiting the latest gas injection techniques to protect the data channel," commented Kubal.

"One difficulty was testing our innovations in an operational steel plant under production conditions. However, by working with Tata Steel UK we are able to undertake full-scale trials."

The potential cost savings to steel manufacturers could be considerable, if the new technique enhances quality control without requiring additional down-time of the plant. Announcing the award, the University of Swansea said that the new technique could "save each steel plant up to £4.5 million a year," and was potentially also applicable to other metals such as aluminium, copper and nickel.

A new University of Swansea spin-out company, Kubal-Wraith Ltd, was formed in January 2018 to commercialize the technology and bring it to market.

Transforming established processes

"This project shows how research and innovation has the potential to transform long-established manufacturing processes," said Bill Bonfield of the Armourers and Brasiers Venture Prize judging panel. "Our prize looks to encourage scientific entrepreneurship in the UK and provide funding to help innovative developments like this realize their potential."

Laser-based monitoring of molten metal has been a topic of research for some time. Potential applications have included the use of laser scattering methods to deliver non-contact temperature measurements, by monitoring the growth of oxide in the melt and the resulting changes in reflected light intensity, relating the rate of intensity reduction to the temperature of the molten metal.

Another avenue of interest has been the application of laser-induced breakdown spectroscopy (LIBS) for online monitoring of the corrosion behavior of molten metal.

Szymon Kubal's research at Swansea in collaboration with Tata Steel has already included a number of non-optical developments and redesigned structural elements to improve the handling of molten metal, but he has also previously discussed the potential for laser scanning technology to play a role in cost-effective metal furnaces and refractories, beyond its established use in the monitoring of refractory wall thicknesses.

In a paper for the 2017 Unified International Technical Conference on Refractories, he commented on the impact that laser scanning could have on the total cost of ownership of converter refractories for operators.

"Modern laser scanning technology offers much more than just information on residual thicknesses of converter lining for safety purposes," he said. "Scan results can provide information on lining temperature; optimize runout time and yield by assisting tapping; aid material selection to eliminate heavy wear zones; and optimize maintenance practices to maximize value in use."