American Society for Testing and Materials (ASTM). Current edition approved March 1, 2006. Published March 2006. Originally approved in 1969. Last previous edition approved in 2004 as A 595 – 04a. 5 p. This specification covers three grades of seam-welded, round, tapered steel tubes for structural use. GradesAand B are of low-carbon steel or high-strength low-alloy steel composition and Grade C is of weather-resistant steel composition.