ASME SA-213/ ASTM A213 Gr. T11 Seamless Tubes

The ASME SA-213/ ASTM A213 Grade T11 seamless tubes, with the nominal composition of 1.25Cr-0.5Mo-Si, are widely used for the construction of boilers, superheaters, and heat exchangers. The tubing are usually furnished in sizes 1/8″ [3.2 mm] in inside diameter to 5″ [127 mm] in outside diameter and 0.015″ to 0.500″ [0.4 mm to 12.7 mm], inclusive, in minimum wall thickness or, if specified in the order, average wall thickness.

Chemical Composition Requirements

Mechanical Properties

Manufacture & Heat Treatment

The ASTM A213 T11 seamless tubes shall be made by the hot-rolling or cold-drawn seamless process. The tubes may be furnished in two heat treated conditions: full or isothermal annealed; or normalized and tempered (N+T). Especially, if N+T is adopted, the tempering temperature shall be no less than 650°C [1200°F].

Applicability in ASME Codes & Maximum Use Temperature

The ASME SA-213/ ASTM A213 Gr. T11 seamless tubes are permitted for use in a series of ASME Construction Codes covering Section I, Section III, and Section VIII. Tables 1A, 2A, and 5A of ASME BPVC Section II Part D have provided maximum allowable stress values, design stress intensity values, and maximum allowable stress values, respectively, for ASME SA-213/ ASTM A213 T11 for elevated metal temperatures in different Construction Codes. The maximum use temperatures are listed in the table below.

The ASTM A213 T11 seamless tubes are primarily used for the construction of boilers, superheaters, and heat exchangers. When working at elevated temperatures, steam decomposes at metal surfaces to hydrogen and oxygen and may cause steam oxidation of steel, which is somewhat more severe than air oxidation at the same temperature. Fluctuating steam temperatures tend to increase the rate of oxidation by causing scale to spall, which exposes fresh metal to further attack. As a rule of thumb, given the metal surface oxidation criteria, the maximum use temperature of Grade T11 tubes is 565°C [1050°F]; given the consideration; given the strength criteria of metal midsection, the maximum used temperature of Grade T11 tubes is 560°C [1040°F].