1. Scope

1.1 This specification covers seamless, welded ferritic, and martensitic stainless steel pipe intended for high-temperature and general corrosive service.

1.2 Most of the grades are commonly known as the straight chromium type and are characterized as being ferromagnetic.

1.3 High-chromium, ferritic alloys are highly sensitive to notch brittleness on slow cooling to ordinary temperatures. This feature should be recognized in the use of this material in the as-welded condition in sections thicker than 0.250 in. [6.3. mm].

1.4 Optional supplementary requirements are provided for pipe where a greater degree of testing is desired. These supplementary requirements call for additional tests to be made and, when desired, one or more of these may be specified in the order.

1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the "M" designation of this specification is specified in the order.

NOTE 1--The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as "nornina diameter," "size," and "nominal size."