ASTM A 250

This guide covers standard specification for several grades,designated T1, T1a, T1b, T2, T11, T12, and T22, of minimum-wall-thickness,electric-resistance-welded, carbon-molybdenum and chromium-molybdenumalloy-steel, boiler and superheater tubes. Product analysis shall be donewherein the material shall conform to the required chemical composition forcarbon, manganese, phosphorus, sulfur, silicon, molybdenum, and chromium. Thematerial shall conform to the required tensile properties, namely: tensile strength,yield strength, and elongation. The computed minimum elongation values forsteel with decreasing wall thickness shall be given. The tubes shall have ahardness not exceeding the specified values for Brinell hardness and Rockwellhardness numbers. When the final heat treatment is in a continuous furnace, thenumber of tubes of the same size and from the same heat in a lot shall bedetermined from the given size of the tubes. Required mechanical tests such astensile test, flattening test, flange test, reverse flattening test, hardnesstest, and hydrostatic or nondestructive electric tests, shall be performed onthe steel specimen.