There it is: our celebrated Steam Engine Number 7. The original is on display on the former factory grounds behind the museum, where you can even see it in action.
Here, you can see it in the large-scale photograph on the wall – and in the model. The latter demonstrates how the steam engine drove the ingot rolling line in the Blooming Mill. You can set it in motion by pressing the button on the right.
The steel ingots are transported in railway wagons and unloaded by a crane. In a continuous process, the ingots are propelled through the pusher furnace, where they are heated to the processing temperature of eleven hundred degrees Celsius. The red-hot, glowing ingots are then moved on to the three roll stands, which are powered by the steam engine.
The roughing stand and the finishing stand each consist of three rollers, while the polishing stand at the rear has two. Each steel ingot is guided through the rollers via the rockers: it’s lifted, and then makes the first pass through the roller. The ingot is then lowered once again, brought back, lifted again, and makes a second pass.
After twice completing six passes, the ingot, which was originally around 1.5 metres or four feet long, has become a bar that’s 80 metres or over 260 feet long. That’s now guided on roller tables to the blank shears, where it’s cut into smaller panels. On the right of the model, you can see a stack of blanks, the Blooming Mill’s end product. The blanks then moved on to the sheet rolling mill, where they were rolled out as required, into sheets that could be as thin as one millimetre.
Steam Engine Number 7 powered all three of the Blooming Mill’s roll stands from 1912 to 1990, with almost no downtime. And it was still fully functional when it was decommissioned in 1990.
All depictions: © Hüttenmuseum Thale
