This standard applies to heat exchangers, condensers and similar heat exchanger and condenser erw carbon steel pipe with a minimum wall thickness. Usually provides steel pipe size outside diameter smaller than 3in (76.2mm), can also provide other dimensions of the tube, these tubes meets all other requirements of this standard. Mechanical performance requirements do not apply to the inner diameter of less than 3.2mm or the thickness is less than 0.015in (0.4mm) of the tube.
Tube hardness value shall not exceed 72HRB
The finished steel should not with oxide skin, slight oxide should not be seen as the oxide.
Carbon steel pipe with a resistance welding process
900 ℃ or higher temperature necessary after a steel pipe by welding heat treatment, followed by air cooling, or cooling in a controlled atmosphere furnace. Cold drawn tubes after a cold drawn by a final make heat treatment temperature of 650 ℃ or higher.