ASTM A 376
This specification covers seamless austenitic steel pipe intended for high-temperature central-station service. The grades covered are five H grades and two nitrogen grades. Pipe may be either hot finished or cold finished, with a suitable finishing treatment. All pipes shall be furnished in the heat-treated condition unless the order specifically states that no final heat treatment shall be applied. Tensile tests, hydrostatic test, nondestructive electric tests, ultrasonic tests, eddy-current tests, tension tests, and flattening tests shall be made to conform to the requirements specified.