For joining difficult to weld high carbon steels and dissimilar metal combination when no exact specification of the base metal exists
Ferritic/Martensitic stainless have chromium levels of 12% - 18% as the main alloying element and have carbon levels to
enable air hardening to a predominantly martensitic structure. Accordingly, detailed attention must be paid to both pre-heat
and PWHT during and after welding.
Standard austenitics are those in the ASTM 3XX series and should, in the main, be welded with matching electrodes and for
all fabricational purposes should be considered non-hardenable, non-heat treatable and thus show no PWHT requirement.