Recycling railroad steel into angle iron.. Sales video, but fun to watch the operation... (found this on another list, thought it was interesting for metalworking content)
In case you ever wondered why your drill won't go through that angle iron you salvaged from an old bed frame or street sign:
Carla
Why does your money only create jobs when government spends it for you? Because SHUT UP.
If you get a look at the alloy makeup for train rails, you'll see why that is. It's potentially quite hard -- carbon runs up to 0.80% by the ASTM standard, and it contains manganese (1%), which augments the hardening effect of the carbon. As-rolled, it comes in around 400 Bhn (Rc 43). It may actually be harder when re-rolled, because the thinner sections generally cause more work-hardening.
On top of that, older-spec rails can contain relatively high levels of sulfur, phosphorus, and silicon. You get some weird microstructures when you heat that and re-roll it.
Rolled as rails, the steel is intended to have a totally pearlitic structure. It's hard and strong but other properties, such as elongation, can be lousy. So it's likely to be nasty to cut, a bugger to weld, very hard but with very little ductility.
'Great for a railroad. Not bad for a bedframe. Otherwise, IMO, it's junk.
Welding OBF old bed frame isn't very reliable either, IME.. I've had MIG welds that completely pulled out when stressed to check for integrity.
I haven't tried brazing, but that may be the most reliable method of joining OBF, other than punching and riveting as it's done in manufacturing bed frames.
Cutting with a thin reinforced abrasive disk is likely the most efficient method of cutting, since random hard spots will wipe out saw teeth quickly.
I also haven't tried carbide drilling.. maybe someone could comment whether that works very well.
I've found that normal mill steel is much less problematic.. even if it's not free, projects progress more quickly.
Well, rails are from around 0.50 to 0.80 percent carbon -- newer rail has higher carbon. As rails, it's hypoeutectic pearlite -- layers of carbide laminated with layers of ferrite. The carbon may go into solution when it's heated and re-rolled, but don't count on it.
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