1.1 This specification covers seamless carbon steel pipe for high-temperature service (Note 1) in NPS 1/8 to NPS 48 [DN 6 to DN 1200] (Note 2) inclusive, with nominal (average) wall thickness as given i This specification covers carbon steel pipe for high-temperature service. These pipes are suitable for welding, bending, flanging, and similar forming operations. Mechanical testing of the specimens shall include tensile, bending, flattening, hydrostat