Study on warm caliber rolling of magnesium alloy

The warm caliber rolling was experimented using the AZ31 magnesium alloy round bar of 20mm in diameter machined from cast ingot materials. In warm caliber rolling in final size of 10mm in diameter at 623K via 8passes, each width-spreading, the change of each microstructure, X-ray analysis of final texture and final mechanical properties were investigated. Microstructure, texture and mechanical properties of warm caliber rolled round bar at 473K via latter 4passes were compared with those at 623K consistently. Obtained results are as follows: (1) The width-spreading in caliber rolling of round bar is relatively large, compared with that in flat rolling of the flat bar. The largeness of width-spreading of round bar makes the shape control of cross section difficult, and causes the cracks around the free surface. (2) Finer microstructure and inclined c axis of hexagonal lattice of 10 degrees to vertical direction of the rolled surface are obtained in warm caliber rolling at 473K via latter 4 passes. (3) The process of warm caliber rolling at 473K via latter 4 passes is more useful for strengthening of rolled round bar than that at 623K consistently.