Monitoring Defect Levels in Steel During the Manufacturing Process. Iain Baillie Mentors: Kevin Neailey (WMG) Steve Dixon (Physics)

Contents Problem Definition Objectives Methodology Innovations The EngD Competences Conclusions

Slab Casting Process Overview Ladle Ladle Turret Tundish Slab Mould Torch Cutter Spray Chamber

Product length is approximately 6 to 12m Slabs, Blooms & Billets Slab 2030 x 305 mm Bloom 755 x 385 mm Billet 180 mm2 Product length is approximately 6 to 12m

Some Typical Casting Defects Transverse Cracks Corner Cracks Pinholes Longitudinal Mid-Face Cracks Star Cracks Sub-Surface Porosity Inter Columnar Cracking Centreline Segregation Spider Cracks Off-Corner Cracks Longitudinal Edge Cracks/Splits Plus Scale & Oscillation Marks

Why Use Laser-EMATs? Give ‘real time’ feedback to concast operators. Be used to guarantee product quality and suitability for downstream Corus & External customers. Reduce the amount of scarfing (yield losses etc). Minimise “eye-ball” inspection. Could be linked into plant “quality tracking” software. Validate models. Size products. Ensure no molten core!

How to Measure Defects? Need to consider the environment of a continuous casting plant; e.g. harsh, hot, dusty, machine vibrations. No “off the shelf” product exists. It would be beneficial if both surface defects and internal defects could be found.

The Selection of the Optimal Technique. Advice was gathered from Corus research scientists and from steel plant technical personnel. No ‘off-the-shelf’ technique was available A review of the literature was conducted to assess all the various options available that had the potential for use for continuous casting. The Laser-EMAT technique was found to be the most viable one, but would require significant refinement to reach the prototype stage. Laser-EMATs use ultrasonics; and can therefore be used to find both surface and internal defects.

Laser-EMATs An EMAT is an “ElectroMagnetic Acoustic Transducer”. It does not need any gel or water coupling as it is electromagnetically coupled. The EMAT can be positioned a few millimetres above the surface of the hot steel. Laser generates ultrasound EMAT probes can be used to detect it.

What Happens When the Laser Hits?

Fundamental Ultrasonics The laser generates the ultrasound The EMAT detects the ultrasound

Moving steel (at room temperature) Laboratory Trials Moving steel (at room temperature)

Trolley Based Inspection

Side view of billet being inspected LASER Slot EMAT x Slot EMAT LASER x EMAT LASER Slot x

Moving The Steel in 2mm increments Case 3 Case 1 Case 2*

Moving The Steel at Constant Velocity

Laboratory & Pilot Trials Experiments to ensure EMATs work efficiently at high temperatures.

Water-Cooled EMAT

Water-Cooled EMAT

Moving steel (at room temperature) Pilot Scale Trials Moving steel (at room temperature)

Cold Inspection on TTC Rolling Mill

Results from cold tests on the rolling mill Defect

Pilot Scale Trials Moving steel (at 800°C)

Hot Inspection on Blue Bay Rolling Mill

Results from the hot test on the rolling mill - 800°C. Defect /(Arbitrary units)

Caster Installation

The EngD Competences Expert Knowledge of an Engineering Area Continuous Casting Process Laser & EMAT ultrasonics Software control and data acquisition via LabVIEW software The appreciation of engineering and development culture Working closely with research group within Physics Dept at Warwick and at R,D&T with Corus. Able to work and communicate at all levels to explain aims and objectives. MSc Modules in this area taken. Project and Programme Management Skills Wrote EU proposal (RFCS) Project leader and coordinator for the RFCS project (1M Euro) – a multi-national collaboration with other steel companies for inspection techniques.

The EngD Competences 2 Teamwork and Leadership I work in a matrix R,D&T organisation, and lead the Laser-EMAT project (which I am also the project champion for) MSc Modules in this area taken. Oral and Written Communication Skills Have presented the Laser-EMAT work to EU conferences; specifically for general steel & management audiences, dedicated casting conferences and for dedicated NDT conferences. Winner of IOM3 Lecture Competition. Technical Organisation Skills Have managed to achieve project objectives; good design processes of equipment, software interpretation & modelling, software design, practical engineering & instrumentation experience. Financial project planning and control Have controlled project spending (hours spent, capital expenditure, sub-contractors, component purchases, EU exchange rates and coordinated EU partners forms for the project proposal and mid-term financial reporting)

The EngD Competences 3 Ability to apply skills in new and unusual situations The casting process is somewhat unique in terms of industrial ‘robustness’. Laser-EMAT technique very much the ‘cutting edge’ Ability to seek optimal, viable solutions for complex engineering problems and to seek out relevant information sources. Have met with many of the experts in casting, NDT and laser-EMAT fields. Conferences Have produced two in-depth literature reviews Have worked hard to ensure prototypes are ‘right first time’ and to ensure the experimental research is as rigorous as possible. MSc Modules in this area taken.

Conclusions EMAT probes have been optimised and water-cooled. They can measure ultrasonic waves at temperatures in excess of 1000°C. A trolley based system has been made that can test steel samples easily, with a high degree of automation. Software has been designed to control the laser, trolley system and to acquire the ultrasonic data. For the first time in the world, Laser-EMAT inspection has revealed a defect in hot (800°C), as-cast steel. An enhanced Pilot Plant is due to be finished at Corus shortly and the Laser-EMAT prototype can be tested on this.