1.1 This specification covers quenched-and-tempered carbon steel and high-strength low-alloy steel plates of structural quality for welded, riveted, or bolted construction.

1.2 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 used.

1.3 Material under this specification is available in four grades as follows:

Grade	YieldStrength,min, ksi[MPa]	Tensile Strength,ksi [MPa]	Maximum Thickness, in. [mm]
A	50 [345]	70-90 [485-620]	11/2 [40]
B	60 [415]	80-100 [550-690]	21/2 [65]
C	A	A	2 [50]
D	75 [515]	90-110 [620-760]	3 [75]

^AVaries with thickness. See Table 1.

1.4 The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the SI 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.