Unistrut™ is not Shitistrut©

  This shouldn't need to be said, buuut... here we are.

  The object on top is inexpensive sliding door track.  As you can see, it is the thickness of five note cards.  What you can't see from this photo is that it's not galvanized, only painted, and I assure you it is made of a "steel" which can only be called "steel" outside of the USA.

 And finally, what this object most definitely is not, is structural material in any way, shape, or form... even if its form resembles the form of the other object, to a casual observer.

 So where do you think I found it?  When I first opened one of the access panels in the so-called "ceiling" of my garage, I found that stuff nailed (!) up to a roof rafter over the opening.  At first I thought it was being used as a structural brace of some kind.

 And then, in dawning horror, the awful truth struck him,
like a sopping wet Lovecraftian metaphor: someone had
used this disgusting material for lifting or hoisting!

  Ahem, so the other stuff in the photo is actual, name-brand Unistrut.  It is made from, depending on (probably) region and market, either S315MC or S275 mild steel plate.  These have known properties anyone can look up, if they need to know how strong the stuff is.  This Unistrut was hot-dip galvanized, so it is unlikely to rust - in Colorado - in my lifetime, except at the cut ends... which of course can just be coated or painted.  (you can also get it plain, which is nice if you plan to weld to it)

 Notice the material it is folded from is literally three times the thickness of the sliding door channel's mystery meat.

 Now here's the problem: real Unistrut-compatible fittings will go into some versions* of the sliding door track / channel, and this is A Very Bad Thing, if someone were to naively assume that "steel stuff is like, steel stuff, dude".

 Now then, the worst steel on the American market, which is to say, the lowest tensile strength, the least-restrictively-defined, the least pure, and worst-performing steel that can be sold as steel in the USA is called A-36, and it's sorta junk†.  The 36 literally stands for 36,000 PSI, which is the yield strength it's expected to exhibit.  If that sounds like a lot, understand that high performance steels go up to at least 180,000 PSI.  The two grades of very basic, low-alloy mild steel that I mentioned above, from which Unistrut is made, are markedly better quality steel than A-36.

 For some reason after I found that in the ceiling space, I threw it into my stock pile, despite there being almost no legitimate reason for that - not even its original purpose - in my life.  So right after I took the photo above, about twenty minutes ago, I threw that shit into the alley for the scrappers to pick up.  It will be gone in a day or two, and some industrious soul will make a few pennies from it.

____________________________________________________________________
* by the way, home-owners and handimen: there is no industry standard for sliding
door track, so if your hardware is antique, or just different from what you can find
in the local hardware store, tough luck, keep looking, or replace it all from scratch

† and yet it is provably better than Random Mystery Steel From China, India, or
Mexico, because it is an actual specification against which the product is tested.