Effect of annealing time on bending performance and microstructure of C19400 alloy strip

Abstract The effect of annealing time on the bending properties and microstructure of cold-rolled C19400 alloy was studied by transmission electron microscopy, scanning electron microscopy, and optical microscopy. With the increase in annealing time, the bending properties of the alloy first increased and then decreased, and the elongation increased from 8.33% in cold-rolled state to 11.58% after annealing for 60 min, which increased by 39.02%, and then decreased to 10.0% after annealing for 90 min. Within the experimental range, the bending performance is the best when the annealing time is 60 min. When the relative bending radius is 0.4, the outer surface of the bending part of the alloy changes from a large number of microfine cracks before annealing to the disappearance of cracks after annealing. The analysis shows that the decrease in the dislocation density, the ordering of the dislocation structure, and the refinement of the precipitated phase are the keys to improving the bending performance of the strip after annealing.