ASTM A204 / A204M Grade A/Grade B/ Grade C Standard Specification for Pressure Vessel Plates, Alloy Steel, Molybdenum.
ASTM A204 standard 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.
ASTM A204 Grade A/Grade B/ Grade C steel have different strength levels as follows:
Grade A ---tensile strength ksi(mpa) ---65-85 [450-585]
Grade B ---tensile strength ksi(mpa) ---70-90 [485-620]
Grade C ---tensile strength ksi(mpa) ---75-95 [515-655]
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 as follows:
Grade A ---max thickness in.(mm)---6 [150]
Grade B---max thickness in.(mm)---6 [150]
Grade C---max thickness in.(mm)---4 [100]
