Increasing the number of pixels on the focal plane array of a thermal imaging camera allows the user to find smaller problems at greater distances. And from a health and safety standpoint alone that’s important when the user in question is studying the thermal performance of steel emerging from a furnace. For the same reason, the ability to control the camera from a laptop via Firewire is invaluable. These factors, in combination with a video capture rate of up to 50 frames a second, attracted Corus to FLIR Systems’ ThermaCAM SC640 thermal imaging camera. This is currently being used by the Long Product Rolling department of Corus R&D to monitor and improve the process of reheating, rolling and finishing of long products such as rails.
Temperature is a key factor during rolling. If the material is too cold, the loads and torque generated are elevated, increasing the risk of equipment damage. Furthermore, the temperature at the end of the rolling process has a significant effect on the final properties of the steel. Temperature also needs to be measured against time for the steel cooling process. Various acceleration techniques are employed for this purpose, such as forced air or spray cooling, which reduce the temperature of the steel in the optimum time to achieve certain desired material properties.
“We are using our new SC640 to measure the temperature of the rolled steel at any point from furnace dropout, when it is roughly 1,300oC, to the final cold product,” development engineer, Chris Oswin explains. “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.”
Corus is no stranger to thermography and 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 FLIR product were primarily its video mode and remote control features that allow the R&D team to conduct more detailed work in compliance with health and safety requirements. Its ability to maintain 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 1,300oC to ambient.
Whereas a standard 320 x 240 focal plane array has 76,800 pixels, the SC640 has 307,200, enabling 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 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,” Mr Oswin adds.
No infra red specialist other than FLIR Systems manufactures its own lenses, and this has allowed the company to develop and produce dedicated high-powered lenses for this camera. The high-precision germanium lenses are designed to take full advantage of the high-resolution focal plane array sensor. A full range of lenses is available, including a 12, 25 and 45 degree, plus a 50 micron microscope lens.
“Thanks to the SC640, we can now look closely at transient processes - something we were unable to do before.” Chris Oswin concludes. “In 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.”