are extensively
used for elevated-temperature applications
in the power and petroleum refinery industries.
The chromium content of these steels
varies from 0.5 to 9%, and the molybdenum
content from 0.5 to 1.0% (Table 3). They are
usually supplied in the normalized-and-tempered
or the quenched-and-tempered condition.
Because these materials have reasonable
hardenability, adequate precautions must be
taken to avoid weld-related hydrogen-induced
cracking (Ref 5). The service application frequently
imposes additional requirements on the
welding of these steels. For example, in the
power industry, these materials are required for
their creep resistance, and the weld metal and
HAZ must provide adequate creep properties.
The corrosion environment in refineries requires
that the maximum HAZ hardness be limited
to avoid corrosion cracking.