ASTM -A179/A179M Standard Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
Tubes shall be made by the seamless process and shall be cold drawn.
Tubes shall be heat treated after the final cold draw pass at a temperature of 1200°F [650°C] or higher.
Surface Condition Finished tubes shall be free of scale. A slight amount of oxidation will not be considered as scale.
The steel shall conform to the following requirements as to chemical composition:
|Phosphorus, max, %||0.035|
|Sulfur, max, %||0.035|
The tubes shall have a hardness number not exceeding 72 HRB.
Mechanical Tests Required
Flattening Test—One flattening test shall be made on specimens from each of two tubes from each lot or fraction thereof.
Flaring Test—One flaring test shall be made on specimens from each of two tubes from each lot or fraction thereof.
Flange Test—When specified as a substitute for the flaring test, for tubes having a wall thickness (actual mean wall) less than 10 % of the outside diameter, one test shall be made on specimens from each of two tubes from each lot.
Hardness Test—Rockwell hardness tests shall be made on specimens from two tubes from each lot. The term lot applies to all tubes, prior to cutting, of the same nominal diameter and wall thickness which are produced from the same heat of steel. When final heat treatment is in a batch-type furnace, a lot shall include only those tubes of the same size and the same heat which are heat treated in the same furnace charge. When the final heat treatment is in a continuous furnace, a lot shall include all tubes of the same size and heat,heat treated in the same furnace at the same temperature, time at heat, and furnace speed.
Hydrostatic Test—Each tube shall be subjected to the hydrostatic test, or, instead of this test, a nondestructive electric test may be used when specified by the purchaser.