Group II Alloys. To overcome some of the
difficulties and to improve weldability, several
of the standard Group I ferritics have been mod-
ified. These Group II ferritic stainless steels
contain lower levels of carbon and chromium,
along with additions of ferrite stabilizers (see
Table 2). Applications of these alloys involve
exposure to high temperatures, such as for
quenching tanks and annealing boxes, and also tanks for agriculture sprays, transformer cases, and automotive applications.
The prototype of the Group II alloys is type
409 (UNS S40900), which typically contains
0.04% C, 11% Cr, and 0.5% Ti. Largely
because of its consumption in the automotive
industry, the current production of type 409 in