Effect of Rolling Method and Speed on Microstructure and Mechanical Properties of Hot Rolled ZK60 Magnesium Alloy Plate

ZK60 magnesium alloy plates in the homogenized annealed state were hot rolled for 4 passes at different rolling speeds of 512, 768, 1 024 mm·s^-1 , and the rolling methods included unidirectional rolling (4 passes with the same direction) and cross rolling (direction of the first and the third passes perpendicular to the second and the forth passes). The effects of rolling method and speed on the microstructure and mechanical properties of magnesium alloy plate were studied. The results show that compared with those by unidirectional rolling, the microstructure uniformity and comprehensive mechanical properties of cross-rolled magnesium alloy plates were relatively good. With the increase of rolling speed, the dynamic recrystallized grain size decreased first and then increased, the tensile strength increased and then decreased, and the percentage elongation after fracture increased. ZK60 magnesium alloy plates with good microstructure and mechanical properties could be obtained by cross rolling and rolling speed of 768 mm·s^-1; at this time, the complete recrystallization of the magnesium alloy plate basically occurred, and the grains were fine and uniform; the tensile strength was 322.4 MPa, and the percentage elongation after fracture was 15.7%.