Method for producing magnesium alloy plate and magnesium alloy plate

Abstract

The present invention provides a method for producing a magnesium alloy sheet capable of producing a magnesium alloy sheet having excellent plastic workability such as press workability. The method of the present invention includes rolling a magnesium alloy blank with a reduction roll. The rolling includes controlled rolling performed under the following conditions (1) and (2) wherein M (% by mass) is the Al content in a magnesium alloy constituting the blank: (1) the surface temperature Tb (° C.) of the magnesium alloy blank immediately before insertion into the reduction roll satisfies the following expression: 8.33× M +135≦ Tb ≦8.33× M +165 wherein 1.0≦M≦10.0; and (2) the surface temperature Tr of the reduction roll is 150° C. to 180° C.

1 - 10 . (canceled) 
     
     
         11 . A magnesium alloy sheet produced by a method comprising a step of:
 rolling a magnesium alloy blank with a reduction roll;   wherein the rolling includes controlled rolling in which the surface temperature Tb (° C.) of the blank immediately before insertion into the reduction roll satisfies the following expression:
   33 M+ 135≦ Tb≦ 8.33× M+ 165
 
   wherein 1.0≦M≦10.0   M and M (% by mass) is the Al content in a magnesium alloy constituting the blank; and   the surface temperature Tr of the reduction roll is 150° C. to 180° C.   
     
     
         12 . The magnesium alloy sheet according to  claim 11 , wherein an amount of segregation present at a centerline in a thickness direction of the magnesium alloy sheet is 20 μM in the thickness direction. 
     
     
         13 . The magnesium alloy sheet according to  claim 11  or  12 , wherein the magnesium alloy has an Al content M of 8.5 to 10.0% by mass and further contains 0.5 to 1.5% by mass of zinc, and the magnesium alloy sheet has a tensile strength of 360 MPa or more, a yield strength of 270 MPa or more, and an elongation at breakage of 15% or more at room temperature. 
     
     
         14 . The magnesium alloy sheet according to  claim 11 , wherein a yield ratio is 75% or more. 
     
     
         15 . The magnesium alloy sheet according to  claim 11  or  12 , wherein the magnesium alloy has an Al content M of 8.5 to 10.0% by mass and further contains 0.5 to 1.5% by mass of zinc, and
 the magnesium alloy sheet has a tensile strength of 120 MPa or more and an elongation at breakage of 80% or more at 200° C., and a tensile strength of 90 MPa or more and an elongation at breakage of 100% or more at 250° C. 
 
     
     
         16 . The magnesium alloy sheet according to  claim 11  or  12 , wherein the magnesium alloy has an Al content M of 8.5 to 10.0% by mass and further contains 0.5 to 1.5% by mass of zinc, and
 the magnesium alloy sheet produces neither crack nor flaw in a surface in a bending work under the conditions of 200° C. or more and a bending characteristic value (bending radius R/thickness t) of 1.0 or less. 
 
     
     
         17 . The magnesium alloy sheet according to  claim 11  or  12 , wherein the magnesium alloy has an Al content M of 8.5 to 10.0% by mass and further contains 0.5 to 1.5% by mass of zinc, and
 the magnesium alloy sheet produces neither crack nor flaw in a surface in a press work under the conditions of 200° C. or more and a bending characteristic value (bending radius R/thickness t) of 1.0 or less.