If you really want to know what you are buying, you need to have a conversation with the supplier about what ASTM standard the tubing is built to, and make it plain you want to get a copy of the material certifications from the supplier that apply to the particular batch of material that you are buying. After determining what standards the supplier has available, you can look up the chemistry, dimensions, tolerances, grade, and manufacturing method in the ASTM standards books.
Without the certs from a reputable supplier, you really don’t know what you have. You should determine what standard and grade you want, and order accordingly. The tubing itself should also have the standard painted on the OD from the manufacturer.
