scope:

These specifications are intended as a general guide for the purchase of alloy-steel pipe and to serve as a basis for agreement between the manufacturer and the purchaser as to details not specifically covered.

These specifications cover nominal (average) wall seamless alloy-steel pipe intended for high-temperature service. Twelve grades are covered, including nine ferritic steels and three austenitic steels, designated P 3a, P 15,etc. (Note1). The maximum temperature at which the pipe will be operated in service shall be stated in the order. Selection will depend upon design, service conditions, mechanical properties, and the high-temperature characteristics.