ASTM A249 TP321 Welded Boiler Tubes

ASTM A249 TP321 Welded Austenitic Steel Tubes intended for such use as boiler, superheater, heat exchanger, or condenser tubes.

Description

ASTM A249 TP321 Welded Boiler Tubes
ASTM A249 TP321 Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
Standard:ASTM A249/A249M
Standard Specification for
Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
ASTM A249 TP321 Welded Boiler Tubes covers nominal-wall-thickness welded tubes and heavily cold worked welded tubes made from the austenitic steels, ASTM A249 TP321 Welded Austenitic Steel  Tubes intended for such use as boiler, superheater, heat exchanger, or condenser tubes.
ASTM A249 TP321 Welded Boiler Tubes sizes and thicknesses usually furnished to this specification are 1 ⁄ 8 in. [3.2 mm] in inside diameter to 12 in. [304.8 mm] in outside diameter and 0.015 to 0.320 in. [0.4 to 8.1 mm], inclusive, in wall thickness.
Manufacture
The welded (WLD) tubes are made from flat-rolled steel by an automatic welding process
Subsequent to welding and prior to final heat treatment, the tubes shall be cold worked either in both weld and base metal or in weld metal only.
Heavily cold worked (HCW) tubes are made by applying cold working
Heat Treatment of ASTM A249 TP321
Grade UNS Number Solutioning Temperature, min or range Quenching Method
TP321 S32100 1900 °F [1040 °C] C Quenched in water or rapidly cooled by other methods.
A solution annealing temperature above 1950 °F [1065°C] may impair the resistance to intergranular corrosion after subsequent exposure to sensitizing conditions inTP321.
Chemical Composition of ASTM A249 TP321
Grade
UNS
Designation
 Composition, %
Carbon Manganese Phosphorous Sulfur Silicon Chromium Nickel Nitrogen Other
TP321 S32100 0.08 2.00 0.045 0.030 1.00 17.0-19.0 9.0–12.0 0.10
Ti 5(C+N)-
0.70

Mechanical Properties of ASTM A249 TP321

Grade
UNS
Designation
Tensile Strength,
min, ksi [MPa]
Yield Strength,
min, ksi [MPa]
Elongation in 2 in. or
50 mm,min, %
Rockwell Hardness
Number,max
TP321 S32100 75 [515] 30 [205] 35 B90
Mechanical property 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.
Mechanical Tests and Grain Size Determinations 
Grain Size
Tension Test—One tension test be made on tubes.
Flattening Test—One flattening test shall be made on specimens from each end of one finished tube
Flange Test—One flange test shall be made on specimens from each end of one finished tube
Reverse-Bend Test—One reverse-bend test shall be made on a specimen from each 1500 ft [450 m] of finished tubing.
Hardness Test—Brinell or Rockwell hardness tests shall be made on specimens from two tubes from each lot .
Hydrostatic or Nondestructive Electric Test—Each tube shall be subjected to either the hydrostatic or the nondestructive electric test.
Heavily cold worked tubes (HCW) are capable of passing the weld decay test listed
Permissible Variations in Dimensions

Standard

 Allowable Outside Diameter Variation in mm Allowable Wall Thickness Variation Exact Length Tolerance in mm
Nominal Diameter Over Under %Over %Under Over Under

ASTM-A249

 Under 25.4 .1016 .1016 +10 -10 3.175 0
25.4-38.1 incl .1524 .1524 +10 -10 3.175 0
38.1-50.8 Excl .2032 .2032 +10 -10 3.175 0
50.0-63.5 excl .254 .254 +10 -10 4.762 0
63.5-76.2 excl .3848 .3848 +10 -10 4.762 0
76.2-101.6 incl .381 .381 +10 -10 4.762 0
Minimum Wall tubes +18% 0 available On request
Surface Condition
The tubes, after final heat treatment, shall be chemically descaled or pickled free of scale. When bright annealing is used, pickling or chemical descaling is not necessary.