This specification covers the specific chromium-molybdenum-vanadium alloy steel plates intended primarily for the fabrication of welded pressure vessels. The steel shall be killed and shall conform to the fine grain size requirement. All plates shall undergo normalization and tempering. Heat and product analyses shall be conducted and the steel shall conform to the prescribed chemical composition in carbon, manganese, phosphorus, sulfur, silicon, chromium, molybdenum, vanadium, titanium, boron, and copper. Tension and notch toughness testing shall be performed on the material and shall meet the required mechanical properties such as tensile strength, yield strength, and elongation.

1.1 This specification covers chromium-molybdenum-vanadium alloy steel plates intended primarily for the fabrication of welded pressure vessels.

1.2 The plates furnished under this specification are required to be normalized-and-tempered. Specification A 542/A 542M includes coverage of the material in the quenched-and-tempered condition.

1.3 The maximum thickness of plates furnished to this specification is limited only by the capacity of the composition to meet the specified property requirements. However, the maximum thickness of plates normally furnished under this specification is 6 in. [150 mm].

1.4 The material is intended to be suitable for fusion welding. Welding technique is of fundamental importance and it is presupposed that welding procedures will be in accordance with approved methods.

1.5 This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable "M" specification designation (SI units), the material shall be furnished to inch-pound units.

1.6 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 must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.