This specification covers manganese-silicon carbon steel plates for use in welded boilers and other pressure vessels. Plates under this specification are produced in two grades. The steel shall be killed and shall conform to the fine austenitic grain size requirement. Tension test shall be made to conform to the requirements specified.

1.1 This specification covers manganese-silicon carbon steel plates for use in welded boilers and other pressure vessels.

1.2 Plates under this specification are produced in two grades. The specified minimum the yield strength decreases on thicknesses over 1 in. [25 mm].

1.3 The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements; however, current practice normally limits the maximum thickness of plates furnished under this specification to 8 in. [200 mm].

1.4 For plates produced from coil, the additional requirements, including additional testing requirements and the reporting of additional test results, of Specification A 20/A 20M apply.

1.5 The values stated in either inch-pound units or SI units are to be regarded separately 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 the specification.