A
268 / SA 268
Standard
Specification for Seamless and Welded Ferritic and
Martensitic Stainless Steel Tubing for General Service
Overview
1.1 This specification covers a
number of grades of nominal-wall-thickness, stainless
steel tubing for general corrosion-resisting and
high-temperature service. Most of these grades are
commonly known as the "straight-chromium"
types and are characterized by being ferromagnetic.
Two of these grades, TP410 and UNS S 41500 in the
specification (Table 1), are amenable to hardening
by heat treatment, and the high-chromium, ferritic
alloys are sensitive to notch-brittleness on slow
cooling to ordinary temperatures. These features
should be recognized in the use of these materials.
Grade TP439 is used primarily for hot-water tank
service and does not require post-weld heat treatment
to prevent attack of the heat affected zone.
1.2 An optional supplementary requirement
is provided, and when desired, shall be so stated
in the order.
1.3
The values stated in either inch-pound units or
SI units are to be regarded separately as standard.
(A combination of 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.
Technical Information
Specifications 
