ESSC & DUPLEX 2019

The design of an exhaust system has become complicated due to exhaust gas regulation and fuel economy improvement. Therefore ferritic stainless steels for automotive exhaust system should have higher formabilities such as deep drawability and pipe bendability in order to avoid crack during manufacturing automotive parts. Recently, a high formable ferritic stainless steel has been developed for automotive market trends. R-value (Lankford's coefficient) of high formable ferritic stainless steel has been improved by advanced texture-control engineering compared to typical ferritic stainless steel. In this study, initial texture and stored energy of differently processed hot-rolled coils partly related to high formable ferritic stainless steel in laboratory scale were quantified by Electron backscattered diffraction (EBSD) & Kernal average misorientation (KAM) methods. Recrystallized gamma-fiber texture development, closely related to high R-value, in cold rolled and annealed sheets with differently processed HR coils was observed and correlation between stored energy and deformation texture during hot & cold rolling and gamma-fiber development after annealing was discussed. Moreover developed high formable ferritic stainless steels have been applied in exhaust pipes and mufflers and the applicable other industrial parts such as boiler were discussed.