monitoring defect levels in steel during the manufacturing process. iain baillie mentors: kevin...
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Monitoring Defect Levels in Steel During the Manufacturing
Process.
Iain Baillie
Mentors: Kevin Neailey (WMG)
Steve Dixon (Physics)
2
Contents
• Problem Definition
• Objectives
• Methodology
• Innovations
• The EngD Competences
• Conclusions
3
Slab Casting Process Overview
LadleLadleTurret
Tundish
SlabMould
SprayChamber
TorchCutter
4
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
TransverseCracks
Corner Cracks
Pinholes
Longitudinal Mid-Face Cracks
Star Cracks
Sub-Surface Porosity
Inter ColumnarCracking Centreline
SegregationSpider Cracks
Off-Corner Cracks
LongitudinalCorner Cracks
Edge Cracks/Splits
Plus Scale & Oscillation Marks
6
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!
7
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.
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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.
9
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 ultrasoundEMAT probes can be used to detect it.
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What Happens When the Laser Hits?
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Fundamental Ultrasonics
The laser generates the ultrasound
The EMAT detects the ultrasound
12
Laboratory Trials
Moving steel (at room temperature)
13
Trolley Based Inspection
14
15
LASEREMAT
x
x
LASEREMAT
LASEREMAT
x
Slot
Slot
Slot
Side view of billet being inspected
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Case 3
Case 1
Case 2*
Moving The Steel in 2mm increments
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Moving The Steel at Constant Velocity
18
Laboratory & Pilot Trials
Experiments to ensure EMATs work efficiently at high
temperatures.
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Water-Cooled EMAT
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Water-Cooled EMAT
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Pilot Scale Trials
Moving steel (at room temperature)
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Cold Inspection on TTC Rolling Mill
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Defect
Results from cold tests on the rolling mill
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Pilot Scale Trials
Moving steel (at 800°C)
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Hot Inspection on Blue Bay Rolling Mill
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Results from the hot test on the rolling mill - 800°C.
Defect/(Arbitrary units)
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Caster Installation
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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.
– MSc Modules in this area taken.
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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.
– MSc Modules in this area taken.• 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)
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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.
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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.
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