AASHTO - M 270M/M 270
Standard Specification for Carbon and High-Strength Low-Alloy Structural Steel Shapes, Plates, and Bars and Quenched and Tempered Alloy Stuctural Steel Plates for Bridges
|Publication Date:||1 January 2000|
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.
Grades 250 , 345 , 345W [50W], and 690 and 690W [100 and 100W] are also included in ASTM A 36/A 36M, A 572M/A 572, A 588M/A 588, and A 514M/A 514, respectively. When the supplementary requirements of this specification are specified, they exceed the requirements of A 36/A 36M, A 572M/A 572, A 588M/A 588, and A 514M/A 514.
Grades 345W [50W], HPS 485W [HPS 70W], and 690W [100W] have enhanced atmospheric corrosion resistance.
Grade HPS 485W [HPS 70W] has enhanced toughness when supplementary requirements S83 or S84 are specified.
Grades HPS 485W [HPS 70W], 690 , or 690W [100W] shall not be substituted for Grades 250 , 345 , or 345W [50W]. Grade 345W [50W] shall not be substituted for Grades 250  or 345  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.
Supplementary requirements are provided where improved internal quality and notch toughness is important. These shall apply only when specified by the purchaser in the order except that Supplementary Requirement S83 or S84 is mandatory for material designated on the contract drawings as main loadcarrying member components subject to tensile stress.
The values stated in either SI units or inch-pound units are to be regarded 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 must be used independently of the other. Combining values from the two systems may result in nonconformance with this specification.