Corus of approval
January 1st 2008

Increasing the number of pixels on the focal plane array of a thermal imaging camera significantly allows the user to find smaller problems at greater distances. And from a health and safety standpoint alone that's important when that user is studying the thermal performance of steel coming out of a furnace

Health & safety is also the reason that the ability to control the camera from a laptop via Firewire is invaluable. These factors in combination with video capture at up to 50 frames a second therefore made the ThermaCAM SC640 from FLIR Systems the ideal candidate for Corus.

This international company that manufactures steel and aluminium products comprises four divisions, Strip Products, Long Products, Distribution and Building Systems and Aluminium. The new ThermaCAM SC640 was purchased by the Long Product Rolling Department of Corus R & D whose function is to improve the process of reheating, rolling and finishing of long products such as rails.

Temperature is naturally a key factor during the rolling process. If the material is too cold the loads and torques generated during rolling are increased which can damage the expensive capital equipment being used. Furthermore the temperature at the end of the rolling process has a significant effect on the final properties of the steel.

Another part of the process where temperature needs to be measured against time is cooling the steel. Various acceleration techniques are employed for this purpose such as forced air or spray cooling. These reduce the temperature of the steel in the optimum time to achieve the desired material properties.

"We are using our new ThermaCAM SC640 to measure the temperature of the rolled steel at any point from furnace dropout when it is roughly 1300°C to the final cold product," explained development engineer, Chris Oswin. "In the steel industry there are a lot of potential dangers and the higher resolution of this camera allows us to take images further away and in complete safety. The image quality lets us pick-out the temperature of particular parts of the sections as they are cooled whereas with our previous camera we had to rely on an average temperature reading." Thermography is, of course, an established technique employed by Corus and basically the new ThermaCAM SC640 was bought to improve established working practice. However, the driving factor behind the purchase was a project that was going to involve a large amount of work over a period of several months for which a reliable and compact camera was considered a must.

The overriding factors in favour of the ThermaCAM SC640 were primarily the video mode and remote control that would allow the R&D team to conduct more detailed work in compliance with health and safety requirements. The ability of the ThermaCAM SC640 to hold a constant resolution across a wide temperature range is especially important as the R&D team needs to track the cooling of a steel product from 1300°C to ambient.

Whereas a standard 320 x 240 focal plane array has 76,800 pixels, the ThermaCAM SC640 has 307,200. This feature enables dynamic events in Long Products' R&D to be seen in greater detail.

The camera's larger field-of-view has proved useful to the team when comparing the cooling of multiple sections in close proximity to one another. "In the past we took an image of each section and compared the temperature of two or more images," Chris Oswin continues.

"Now we can get multiple sections on one image and make direct comparisons." Up to 8x digital zoom on the ThermaCAM SC640 also enhances the study of smaller targets. After zooming the operator can pan around the LCD display to examine all areas of the image, not just the centre. "This feature and the expanded field-of-view allows us to do far more than we could with our old camera but eventually we hope to invest in further lenses, telephoto and wide-angle," Chris adds.

No infrared specialist other than FLIR Systems manufactures its own lenses.

This has allowed the company to develop and produce dedicated high-powered lenses for this camera. The resultant highprecision germanium lenses have therefore been designed to take full advantage of the high-resolution focal plane array sensor. A full range of lenses is available including a 12°, 25°, 45° and a 50 micron microscope lens.

"Thanks to the ThermaCAM SC640 we can now look closely at transient processes, something we were unable to do before." Chris Oswin concludes. "By comparison with our old camera the new ThermaCAM is also smaller, lighter, easier to use and has a better battery-life so we can use it for longer periods of time and for tasks for which the old camera was just too unwieldy."

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