[Slick61]

portable x-ray analyzers can be had for much less that $20k. If you have a sample of the tubing, grind an area down to bare metal, clean it, then take it to a scrap yard that buys/recycles metal... they should have one. (they can also probably be rented, tho it would be pricey) Altho I don't know that I'd rely upon the results with respect to carbon content (which is the primary alloying element in a plain carbon steel). Ideally, carbon content is best analyzed via combustion. A 1020 plain carbon steel is, in general, pretty similar to an ASTM A36 steel... which would have a minimum yield strength of 36 ksi, and an ultimate tensile strength of 58-80 ksi. The requirements for a plain carbon steel are so loosely defined that a beer can would meet it. Having tensiles pulled would be more involved... and more costly... and definitely destructive. An alternative would be hardness testing with a portable, rebound-type hardness tester. The hardness-to-tensile strength correlation is pretty good for carbon steels. A commercial testing lab could probably get you chemistry & tensile/hardness for $300 or so.