Red-hot Radar Measurements, Kjell Wallin
In 2004 we formed a club, at the initiative of the University of Gävle, which met on Fridays.These were people from industry and the university; we had coffee together and talked about everything, mostly about technology. At that time I was involved in traffic monitoring; I worked on developing the speed cameras that stand along the highways today. I was thinking about a similar concept for railways and was probably the “radar expert” in the gang.
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One person in the group was Åke Lindberg; he worked on documenting various industrial facilities by scanning them. He’d done a job for Sandvik and was asked if he could document their furnaces too. The request came from Håkan Svensson, who is in charge of the furnaces at Sandvik. This particular furnace was 140 m2 and could tolerate heating to 1200ºC.
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From car bottom furnaces, via rotary hearth furnaces to walking beam furnaces
We began by looking at car bottom furnaces using laser technology. The cars travel into the furnace through a large opening and risk destroying the material of the walls. They frequently broke down. We did experiments using laser scanning with 3D Focus and carried on for a while. One drawback was that it only worked when the door was open. It was not an energy-saving solution either, it went counter to the trend, so we ended it. Maybe radar could be the solution?
U.S. researchers had developed so-called Ultra Wide Band Technology in 2002. The advantages were that the radar had an amazing accuracy along with a good ability to penetrate walls. We began experimenting with the method. Sandvik offered us a discarded rotary hearth furnace. It went well and was a breakthrough! We hired a technician to work with the radar and we conducted several experiments. But now we wanted to try something more tangible. Maybe a large-scale plant?
One of the managers at Sandvik said he was more interested in following the billets through the furnace. This was a turning point for our experiments. It felt like it was now or never. So we stood in front of a walking beam furnace. We had started at the periphery and were now at the inner sanctum.
It turned out that the slabs bent upwards inside the furnace. That wasn’t good; there was a risk of “pick up sticks,” where four-ton slabs could end up scattered all over the furnace. We installed sensors on the ceiling of the furnace. That way we could use radar to show how the slabs moved inside the furnace. With our method we could show in detail how this happened. It was a real ‘aha’ experience. Now it was easy to see how the slabs arched. With the knowledge provided by our sensors this could be avoided, so we were no longer needed.
New ground
Now we were in a tricky situation. Someone asked: Can’t we use the technology to measure the slab itself?
We contacted Anders Salwén at Swerea/KIMAB and managed to convince him to think about this. We wrote up a project together with a materials consultant at Sandvik, Patrik Eriksson. Anders Salwén proved to be interested in doing a preliminary study along with our small business Radarbolaget to test an idea that no one had ever tried.
Immediate understanding
But money was needed. We had been in contact with VINNOVA, but were turned down. Then I contacted Bosse Lilja in the spring of 2009. At the same time I called Maria Engholm. At first she was afraid when I said I was calling from Radarbolaget; she thought the cameras had caught her in a speed trap! But she listened and asked me to present the concept to the Triple Steelix Board of Directors.
Patrik and I traveled there, showed OH slides, and gave our presentation. In the afternoon on that same day Maria called to ask how it went. “It’s already decided, you’re getting the money!” It was absolutely fantastic, it felt like the board understood what we were talking about. These ideas were on the cutting edge of technology, requiring both knowledge and imagination, and we could find common ground there!
It went like clockwork. During Phase 1, autumn of 2009, we took measurements, conducted simulations and held project meetings at Sandvik, which provided all the resources we needed. Spring of 2010, Phase 2, we had to rebuild the electronics in the furnace. I submitted a quotation and Sandvik approved it. Last summer we installed all the sensors in the vault. On top of this Sandvik changed the operating system, so there was some delay as a result.
Now we have noticed that it’s too hot for the sensors on the sides of the furnace. But we’ll change that this summer, so it will work out. It’s incredibly hot where we work, you can only be there ten minutes at a time. It's like a sauna. One of our members has his roots in Finland so he’s happy!
We’ve been in contact with a German company that makes steering equipment to guide the steel strip during rolling. It was thanks to KIMAB, which had been asked “Do you know anyone who works with radar?” They mentioned us and two months later we received an inquiry for an order to develop two prototypes for the German company. Now, one year later, they’ve been delivered and will be tested at Germany’s largest steel enterprises.
Now we’re speaking with Jernkontoret prior to Phase 3, which will involve temperature measurements in a full-scale operation. We’ve encountered a huge, sincere commitment. With Triple Steelix as a reference, everything is going great and there’s no looking back.