This specification covers five grades of electric-fusion(arc)-welded straight-seam or helical steel pipe including pipe of NPS 4 and over. The required chemical composition, tensile requirements of the steel, and the tensile requirements of the production welds are presented. Heat analysis of each heat of steel was made to determine the percentage of the elements as per chemical requirements. Tests to be performed shall include one longitudinal tension test for the steel, one reduced-section production weld test for the pipe, and hydrostatic test for each length of the pipe.

1.1 This specification covers five grades of electric-fusion (arc)-welded straight-seam or helical-seam steel pipe. Pipe of NPS 4 (Note 1) and larger with nominal (average) wall thickness of 1.0 in. [25.4 mm] and less are covered. Listing of standardized dimensions are for reference (Note 2). The grades of steel are pipe mill grades having mechanical properties which differ from standard plate grades. The pipe is intended for conveying liquid, gas, or vapor.

Note 1: The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as “nominal diameter,” “size,” and “nominal size.”

Note 2: A comprehensive listing of standardized pipe dimensions is contained in ASME B36.10M.

Note 3: The suitability of pipe for various purposes is somewhat dependent on its dimensions, properties, and conditions of service. For example, for high-temperature service see applicable codes and Specification A691.

1.2 The values stated in either inch-pound units or in SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values in each system are not exact equivalents; therefore, each system is to be used independently of the other.