This specification covers chromium-molybdenum alloy steel plates for welded boilers and pressure vessels designed for elevated temperature service. Materials considered under this specification are available in grades 2, 12, 11, 22, 22L, 21, 21L, 5, 9 and 91. The steel materials shall be killed and shall be thermally treated. The steel specimens shall undergo heat analysis and product analysis and shall conform to the chemical requirements for carbon, manganese, phosphorus, sulfur, silicon, chromium, molybdenum, nickel, vanadium, columbium, boron, nitrogen, aluminum, titanium, and zirconium. The steel specimens shall also undergo tension tests and shall conform to the required values of tensile strength, yield strength, and elongation.

 

 

This specification covers molybdenum alloy steel plates, intended particularly for welded boilers and other pressure vessels. Plates under this specification are available in three grades having different strength levels: Grade A; Grade B; and Grade C. The steel shall be killed. The steel shall conform to the chemical requirements specified. Tension tests on plates shall conform to the requirements specified.                                                                                      

Plates under this specification are available in three grades having different strength levels as follows:

 

Grade	Tensile Strength, ksi [MPa]
A	65–85 [450–585]
B	70–90 [485–620]
C	75–95 [515–655]