ASTM A520 Standard Specification, supplementary requirements for seamless and resistance welded carbon steel pipe products for high temperature service, conforms to the recommendations of boiler structure.


If the edge steel or non-killed steel is used in the manufacture of resistance welded pipe to meet the requirements of specification A520, the strip shall be welded with a single width and shall not be cut lengthwise except edge trimming.


The yield strength at the indicated elevated temperature should not be less than the given value. Yield strength should be determined, which corresponds to the permanent offset of 0.2% of the sample gauge length or the total extension of 0.5% of the gauge length under load.


For many 400 or less pipes, 2% of the total number of pipes or tubes per 50 pipes, tensile test, flight test or warping test should be carried out according to the manufacturer's choice. For batches larger than 400 pipes, one of every 100 pipes or part of them should be tested.


Splitting and warping tests are only applicable to pipes with an outer diameter of less than 6 inches (152.4 mm) and a wall thickness of less than 0.350 inches (8.89 mm).


Many are defined as a group of tubes with the same diameter and wall thickness of the same specification of metal and the same manufacturer.