While on the top deck of a passenger train recently, I saw a passing freight train which puzzled me. The first few cars were open wagons, full (to the top of the wagon) with something that looked very much like steel wool - fuzzy curled texture, dark grey in colour. It looked like it was loose in the car, heaped up in ‘cloudy’ formations much like unspun shhep’s wool. I couldn’t identify it on sight, and I have no idea what it might be.
The next several cars were open wagons half full with cubes of crushed aluminum or steel, presumably headed somewhere to be recycled, so I’m guessing the ‘steel wool’ was also headed for recycling. But what would need to be transported in fine shreds? Was this actual steel that for some reason was in puffs instead of crushed cubes, and if so, why? Any ideas?
It is steel and comes from lathes, milling machines and with as much computer control now they make a lot of long cut strands as that is how it leaves the machine. There is now even auto catching set up so the operator only has to clean up his machine at the end of shift as very little comparatively hits the floor as it did in days of old… Like me. Bawahahaha
That’s neither swarf nor chips, but turnings.
Specifically, chips are small pieces of cast iron as a result of working cast iron - like drilling cast engine blocks. Swarf is very small pieces of steel or non- ferrous metal from machining, typically mixed with cutting or lubricating fluid. Turnings, finally, are also a by-product if machining steel or non-ferrous metal, but in long strands.
The difference is in what you can do with it. Turnings, though a low-value grade of scrap, can be charged into the furnace and melted for new steel, with relatively little yield loss. Swarf, in the other hand, often has too much non-metallic content to charge into a furnace. Even if relatively clean, the small particle size means there is a high surface-to-mass ratio. Meaning much of the material will be oxidized (and so useless in an electric-arc furnace). Further, the small particle size means it will never hit the bath ( molten steel) but more likely end up with the gasses in the baghouse as waste. It consequently has no to negative value, and is more often landfilled than recycled.
I assumed it was turnings from the description, didn’t realize that wasn’t called swarf also. Contaminated chips and the like do have lower scrap value although with tariffs the price and demand for all scrap is climbing.
