ASTM A213 T5 Seamless Low Alloy Steel Tubing

Performance, Size & Wall Thickness

ASTM A213 Gr. T5 seamless boiler tubes, O.D.=38.1 mm, min. wall thickness=2.77 mm, length=6096 mm, supplied to Romania

ASTM A213 T5 seamless tubes refer to boiler, superheater and heat exchanger tubing that are made from the 5Cr-0.5Mo ferritic steel, a typical member of the heat-resistant chromium-molybdenum steel family. The chromium provides improved oxidation and corrosion resistance, and the molybdenum increases strength at elevated temperatures. Compared to grade T11 (1.25Cr-0.5Mo-Si) of ASTM A213, the higher chromium addition of grade T5 of ASTM A213 provides better oxidation resistance but slightly lower stress rupture and creep strength at elevated temperatures. The tubing is usually specified by outside diameter (which is no greater than 5″ [127mm]) and minimum wall thickness (which is 0.015″ to 0.500″ [0.4mm to 12.7mm]). When specified by the purchaser, average wall thicknesses and other diameters may be furnished, provided such tubes comply with all other requirements of ASTM A213 T5. Permissible variations from the specified minimum wall thickness shall be in accordance with ASTM A1016/A1016M; Permissible variations from the specified average wall thickness shall be ±10% of the specified average wall thickness for cold-drawn tubes.

Applications, ASME Codes & Max. Temperature Limits

Due to the improved creep strength and enhanced corrosion resistance, ASTM A213 T5 tubes are widely used in oil refineries, chemical industries, and power generation plants for the construction of heat exchangers, boilers, superheater, etc. Specifically, the tubing used in power plant not only provides improved resistance to oxidation upon exposure to elevated temperature service but also increases resistance to steam erosion. The ASTM A213 T5 tubing also finds extended use in delayed coking facility in petrochemical industries, in which creep strength and resistance to sulphuric corrosion at elevated temperatures are both emphasized.

The UNS designation of ASTM A213 T5 is K41545 with the P number of 5B. Its applicability and maximum temperature limits in ASME Boiler & Pressure Vessel Codes are listed in the table A-1. When used in ASME BPVC, the tubing grade ASME SA-213 T5 shall apply. Besides, ASTM A213 T5 tubing can also be used in ASME B31.1 Power Piping with the maximum temperature limit of 1200°F.

Equivalent & Modified Grades

There are many equivalent steel grades to ASTM A213 T5 including ASTM A234 WP5, ASTM A335 P5, ASTM A369 FP5, ASTM A182 F5, ASTM A387 Gr. 5, ASTM A691 Gr. 5CR, ASTM A336 F5. Its Chinese equivalent is 1Cr5Mo. There are two modified grades available in ASTM A213: Grade T5b, which has increased silicon content that is a ferrite strengthening element and is also effective in increasing the hardness of the tubing; Grade T5c, with reduced carbon content that improves weldability and ductility of the tubing.

Chemical Composition Requirements

Mechanical Properties

Manufacture & Heat Treatment

The piercing process during the fabrication of ASTM A213 T5 seamless tubing. The photo was taken in a pipe mill in Jiangsu Province, China.

The ASTM A213 T5 seamless low alloy tubing shall be made by the seamless process and shall be either hot finished (hot rolled) or cold finished (cold drawn). The tubes shall be fully annealed or normalized and tempered upon client’s requirement. When normalizing + tempering heat treatment is adopted, the tempering temperature shall be no less than 1250°F [675°C]. Tubes, when inserted in a boiler or tube sheet, shall stand expanding and beading without showing cracks or flaws. Superheater tubes when properly manipulated shall stand all forging, welding and bending operations necessary for application without developing defects.

Inspection & Tests

The continuous-roller heat treatment furnace for Cr-Mo low alloy steel tubes.

For ASTM A213 T5 seamless tubes, one tension test shall be made on a specimen from one tube for lots of not more than 50 tubes. Tension tests shall be made on specimens from two tubes for each heat of more than 50 tubes. Brinell, Vickers, or Rockwell hardness tests shall be made on specimens from two tubes for each heat lot. One flattening test shall be made on specimens from each end of one finished tube for each heat lot. One flaring test shall be made on specimens from each end of one finished tube for each heat lot. Each tubing made from ASTM A213 grade T5 shall be subjected to the nondestructive test (eddy current inspection) or the hydrostatic test at the option of the manufacturer.