1.1 This specification covers carbon steel pipe made by the centrifugal casting process intended for use in high-temperature, high-pressure service. Pipe ordered under this specification shall be suitable for fusion welding, bending, and other forming operations. 1.2 Several grades of carbon steels are covered. Their compositions are given in Table 1. 1.3 Supplementary requirements (S1 to S9) of an optional nature are provided. The supplementary requirements call for additional tests to be made, and when desired shall be so stated in the order, together with the number of such tests required. 1.4 The values stated in inch-pound units are to be regarded as the standard.