Edge crack forming mechanism and the countermeasures in as‐sintered 2024 aluminium alloy during cold rolling

Abstract

In order to solve the problem of edge cracking of the as-sintered 2024 aluminium alloy during cold rolling, the initiation mechanisms of edge cracking were studied. The results indicate that the "herringbone" crack parallel to the rolling direction and the "zigzag" crack perpendicular to the rolling direction easily formed during cold rolling. The former mainly occurred during the early stage of cold rolling and was related to the poor plasticity of the as-sintered alloy and the stress state at the end of the rolled plate, whereas the latter appeared in a sample with a rolling reduction of more than 60%, mainly because the grains at the edge of the sample were subjected to threedirection shear stress, which results in cracking along the grain boundaries. However, both herringbone and zigzag cracks propagated along the grain boundary. Finally, the crack-free products were obtained by optimizing the cold rolling process.