The economical combination of strength and corrosion resistance of duplex stainless steels (DSS) has enabled their increasing use in the refining industry. DSS most commonly used today are classified under new grades and have led to improved welding practices.

API TR 938-C covers potential environmental-related failure mechanisms and preventative measures to avoid them; typical material and fabrication specification requirements used by refiners; and examples of applications of DSS within refineries. The report also lists the chemistries and UNS numbers of various common DSS, including some first generation DSS for comparison.