After welding, all tubes shall be heat treated at a temperature of 1650℃F [900℃] or higher and followed by cooling in air or in the cooling chamber of a controlled atmosphere furnace. Cold drawn tubes shall be heat treated after the final cold-draw pass at a temperature of 1200℃F [650℃] or higher.
| 0.18 | |
| 0.27 to 0.63 | |
| 0.035 | |
| 0.035 |
-One flattening test shall be made on specimens from each of two tubes from each lot (Note 1) or fraction thereof.
-One flange test shall be made on specimens from each of two tubes from each lot (Note 1) or fraction thereof.
-One reverse flattening testshall be made on a specimen from each 1500 ft [450 m] of finished tubing.
-Brinell or 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 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.
-Each tube shall be subjected to either the hydrostatic or the nonde-structive electric test. The purchaser may specify which test is to be used.
