ASTM A519 Standard Specification for Seamless Carbon and Alloy Steel Mechanical Tubing.ASTM A519 Standard specification covers for several grades of carbon and alloy steel mechanical tubing, either hot-finished or cold-finished. The steel used in the mechanical tubing may be cast in ingots or may be strand cast.ASTM A519 standard main steel grade:4150,4145,4140,4130,1045,1035,1020,1010,1008 and so on.