Microstructure evolution and texture formation of 16 % chromium ferritic stainless steel following simulated batch annealing treatments in mass production

Abstract

Batch annealing technique is mainly used in industry for improving productivity as a few steel coils were stacked and heated in a bell-type furnace. The microstructure evolution, texture formation and mechanical properties of 16 % chromium ferritic stainless steel under different simulated batch annealing and subsequent cold-rolled annealing conditions were investigated in this work. Results showed that batch annealing process applied in mass production could not produce fully recrystallized and homogenously equiaxed grains even at very high temperatures up to 900 °C for 30 hours. With increased batch annealing temperature, a large number of chromium carbides precipitated in ferrite, while some unstable Fe-carbide precipitates were gradually dissolved. Relatively lower cold-rolled annealing temperature (830 °C) led to finer grains and superior mechanical properties of 16 % chromium ferritic stainless steel. Increased batch annealing temperature improved the intensity of {111}//normal direction γ-fiber textures at the expense of other orientations including {hkl} < 110 > α-fiber, {334} < 4 � 83 > , thus improving the formability of ferritic stainless steel.