1.1 This specification covers heat-treated wrought carbon steel piping fittings with lowered carbon content of seamless and electric fusion-welded construction covered by the latest revisions in ASME B16.9, ASME B16.11, MSS-SP-75, MSS-SP-79 This specification covers heat-treated wrought carbon steel piping fittings with lowered carbon content of seamless and electric fusion-welded construction for low-temperature and corrosive service applications. These fittings are for use in pressure c