Effect of cold rolling on microstructure and material properties of 5052 alloy sheet produced by continuous casting

The microstructure and material properties of continuous cast 5052 alloy sheet in as-received condition (as-received sheet) and laboratory cold rolled condition (lab-processed sheet) were investigated after annealing treatment. Microstructural examinations show that the cold rolling process increases the extent of centerline segregation of second-phase particles. The increase in rolling reduction results in a decrease of grain size and a more random distribution of crystallite orientations. Tensile test results indicate that all the sheets exhibit two-stage strain-hardening behavior. Cold rolling increases the total elongation and n(2)-value in the transverse direction of the lab-processed sheet with a thickness of 1.6 mm. However, further increase in the rolling reduction leads to an increase of UTS with a decrease of elongation and n(2)-value. Furthermore, from the determined forming limit curves (FLCs), it is found that the 1.6 mm thick lab-processed sheet has better stretchability than the as-received sheet, whereas further cold rolling reduces the level of FLC. The effects of cold rolling on the mechanical property and formability are discussed in terms of the microstructural changes. (c) 2006 Published by Elsevier B.V.