This specification covers the standard for heat-treated carbon manganese-silicon steel plates intended for fusion welded pressure vessels and structures. The steel shall be killed and undergo normalization, quenching and tempering. Heat and product analyses shall be performed on the materials and results shall conform to the required values in chemical composition in carbon, manganese, phosphorus, sulfur, silicon, copper, nickel, chromium and molybdenum. Mechanical testing like tension test shall be done on the plates and shall conform to the required tensile strength, yield strength, and elongation.

1.1 This specification2 covers heat-treated carbon-manganese-silicon steel plates intended for fusion welded pressure vessels and structures.

1.2 Plates furnished under this specification are available in the following three classes:

 Class

 Heat
Treatment

 Thickness

Yield
Strength,
min, ksi
[MPa]

Tensile
Strength,
min, ksi
[MPa]

1

Normalized

2¹/₂ in. and under [65 mm and under]

50
[345]

70
[485]

Over 2¹/₂ to 4 in.
[Over 65 to 100 mm]

45
[310]

65
[450]

2

Quenched and tempered

2¹/₂ in. and under [65 mm and under]

60
[415]

80
[550]

Over 2¹/₂ to 4 in.
[Over 65 to 100 mm]

55
[380]

75
[515]

Over 4 to 6 in.
[Over 100 to 150 mm]

46
[315]

70
[485]

3

Quenched and tempered

2¹/₂ in. and under [65 mm and under]

55
[380]

80
[550]

Over 2¹/₂ to 4 in.
[Over 65 to 100 mm]

50
[345]

75
[515]

Over 4 to 6 in.
[Over 100 to 150 mm]

40
[275]

70
[485]

1.3 The maximum thickness of plates furnished under this specification is 4 in. [100 mm] for Class 1 and 6 in. [150 mm] for Class 2 and Class 3.

1.4 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 is to be used independently of the other without combining values in any way.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.