I have a customer asking for ASTM A-513 round bar. I can't find any source for ASTM A-513 in a round bar, only in tubing. I need a .750" OD x .437" ID tube, but I can't locate a .750" OD tube with a thick enough wall to allow me to machine the ID to the required .437". Is ASTM A-513 even available in round bar stock?