1.1 This specification covers centrifugally cast alloy steel pipe intended for use in high-temperature, high-pressure service. 1.2 Several grades of ferritic steels are covered. Their compositions are given in Table 1. 1.3 Supplementary Requirements S1 through S12 are provided. The supplementary requirements provide for additional tests of an optional nature and when desired shall be so stated in the order (Section 4). 1.4