【国外标准】 Standard Specification for Alloy Steel Structural Shapes for Use in Building Framing (Withdrawn 2007)

1.1 This specification covers Grades 50 [345] and 65 [450] alloy steel "W" shapes (rolled wide flange shapes) intended for use in building framing. This steel is a low carbon, copper-containing, alloy steel with a bainitic microstructure that is developed through the control of chemical composition and the use of thermo-mechanical rolling followed by air cooling. The copper is present to enhance precipitation strengthening.1.2 When the steel is to be welded, a welding procedure suitable for the grade of steel and intended use or service is to be utilized. See Appendix X3 of Specification A 6/A 6M for information on weldability.1.3 The shapes are not intended to be galvanized or to be post-weld heat treated at temperatures exceeding 750 °F [400 °C].1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI values are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system is to be used independently of the other, without combining values in any way.1.5 The text of this specification contains notes or footnotes, or both, that provide explanatory material; such notes and footnotes, excluding those in tables and figures, do not contain any mandatory requirements.