This specification covers carbon and high-strength low-alloy steel structural shapes@ plates@ and bars and quenched and tempered alloy steel for structural plates intended for use in bridges. Nine grades are available in four yield strength levels. Grades 250 [36]@ 345 [50]@ 345S [50S]@ and 345W [50W] are also included in ASTM A 36/A 36M@ A 572/A 572M@ A 992/A 992M@ A 588/A 588M@ and A 514/A 514M@ respectively. When the supplementary requirements of this specification are specified@ they exceed the requirements of A 36/A 36M@ A 572/A 572M@ A 992/A 992M@ A 588/A 588M@ and A 514/A 514M. Grades 345W [50W]@ HPS 345W [HPS 50W]@ HPS 485W [HPS 70W] and HPS 690W [HPS 100W] have enhanced atmospheric corrosion resistance (Section 13.1.2). Grade HPS 485W [HPS 70W] or HPS 690W [HPS 100W] shall not be substituted for Grade 250 [36]@ 345 [50]@ 345S [50S]@ 345W [50W]@ or HPS 345W [HPS 50W]. Grade 345W [50W] or HPS 345W [HPS 50W] shall not be substituted for Grade 250 [36]@ 345 [50]@ or 345S [50S] without agreement between the purchaser and supplier. When the steel is to be welded@ it is presupposed that a welding procedure suitable for the grade of steel and intended use or service will be utilized. See Appendix X3 of ASTM A 6/A 6M for information on weldability. For structural products to be used as tension components requiring notch toughness testing@ standardized requirements are provided in this standard@ and they are based upon American Association of State Highway and Transportation Officials (AASHTO) requirements for both fracture-critical and non-fracture-critical members. Supplementary requirements are available but shall apply only if specified in the purchase order. The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text@ the inch-pound units 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. For structural products cut from coiled product and furnished without heat-treatment or with stress relieving only@ the additional requirements of ASTM A 6/A 6M@ including additional testing requirements and the reporting of additional tests@ apply.