Station: [15] Steelworkers' Protective Gear & Tools, Electric Arc Furnace
If you worked as a smelter at over a thousand degrees Celsius, you definitely needed special protective clothing to keep you safe from the heat and from burns – !
... and of course you had to have special tools. The skimmer resembles a broad-bladed Dutch hoe, while the testing spoon looks rather like a large soup spoon. The smelter used the skimmer to remove the slag from the surface of the boiling steel. The skimmer is the smelter’s symbol, just as the hammer and pick represent the miner.
With the testing spoon, the steelworker scooped up a small amount of liquid steel, poured it into a rectangular mould and sent the sample to the lab for testing. The result determined whether the smelting process was complete, or whether certain additives were needed to achieve the desired grade.
Thale’s Siemens-Martin furnaces were shut down in 1984, demolished and replaced by two electric arc furnaces. If you turn around, you can see a model of one such furnace.
Have you noticed the thick copper pipes feeding into the side of the furnace complex? In electric arc furnaces, the heat required for smelting is generated by an electrical process.
The huge boiler beneath the frame is the vessel in which the smelting process takes place. It is brought forward, then the crane charges it with scrap, and it returns to its original position. When the roof is lowered, the carbon electrodes also drop down – those are the big black rods. An electrical current is now passed through the electrodes, creating an electric arc inside the vessel and smelting the scrap at temperatures of around seventeen hundred degrees Celsius.
Between four and a half and six hours later, the smelting process is complete. The vessel is tilted; liquid steel is decanted into the pouring ladle, moved to the casting hall and then poured into moulds. Once the steel has solidified somewhat, the moulds can be removed – leaving behind brightly glowing steel slabs.
All depictions: © Hüttenmuseum Thale