ASTM A250 Standard for ERW Ferritic Alloy-Steel Boiler Tubes

ASTM A250 Standard Specification for Electric Resistance Welded ERW Ferritic Alloy-Steel Boiler Tubes and Superheater Tubes. 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-molybdenum alloy-steel, boiler and superheater tubes. Product analysis shall be done wherein the material shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, molybdenum, and chromium.

The material shall conform to the required mechanical properties, include tensile strength, yield strength, and elongation. The computed minimum elongation values for steel with decreasing wall thickness shall be given. The tubes shall have a hardness not exceeding the specified values for Brinell hardness and Rockwell hardness numbers. When the final heat treatment is in a continuous furnace, the number of tubes of the same size and from the same heat in a lot shall be determined from the given size of the tubes. Required mechanical tests such as tensile test, flattening test, flange test, reverse flattening test, hardness test, and hydrostatic or nondestructive electric tests, shall be performed on the steel specimen.

This specification covers several grades, designated T1, T1a, T1b, T2, T11, T12 and T22, of minimum-wall-thickness, electric resistance welded ERW, carbon-molybdenum and chromium-molybdenum alloy-steel, boiler and superheater tubes.

The tubing sizes and thicknesses usually furnished to this specification are ½ to 5 in. [12.7 to 127 mm] in outside diameter and 0.035 to 0.320 in. [0.9 to 8.1 mm], inclusive, in minimum wall thickness. Tubing having other dimensions may be furnished, provided such tubes comply with all other requirements of this specification.

Mechanical properties requirements do not apply to tubing smaller than 1/8 in. [3.2 mm] in inside diameter or 0.015 in. [0.4 mm] in thickness.

An optional supplementary requirement is provided for non-destructive examination for certain ASME applications.

The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

Within the text, the SI units are shown in brackets.

The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

ASTM Standards

Key Words

boiler tube; resistance welded steel tube; steel tube, alloy; superheater tube; welded steel tube; Boiler/superheater tubes--specifications; Carbon-molybdenum alloy steel--specifications; Carbon steel tube--specifications; Chromium alloy steel--specifications; Chromium-molybdenum steel--specifications; Class codes (for metals/alloys); Electric-resistance-welded (ERW) steel tube --specifications; Ferritic steel tube--specifications; Resistance-welded steel tube; Superheater tubes--specifications; Welded steel tube--specifications;