American Society for Testing and Materials (ASTM). Current edition approved Sept. 10, 2000. Published December 2000. Originally approved in 1978. Last previous edition approved in 1998 as A 758/A 758M – 98. 5 p. This specification covers wrought-carbon steel buttwelding seamless or welded fittings specially processed to ensure better notch toughness than that to be expected in fittings manufactured to the requirements of Specification A 234/A 234M.