Method of producing a magnesium-alloy material

Abstract

The invention offers (a) a method of producing a magnesium-alloy material, the method being capable of obtaining a magnesium-alloy material having high strength, (b) a magnesium-alloy material having excellent strength, and (c) a magnesium-alloy wire having high strength. A molten magnesium alloy is supplied to a continuous casting apparatus provided with a movable casting mold to produce a cast material. The cast material is supplied to between at least one pair of rolls to perform an area-reducing operation (a rolling operation). The rolling operation is performed such that pressure is applied to the cast material using the rolls from at least three directions in the cross section of the cast material. A magnesium-alloy material obtained through the above-described production method has a fine crystal structure and is excellent in plastic processibility.

1 - 7 . (canceled) 
     
     
         8 . A magnesium-alloy material obtained through a production method comprising:
 a casting step for obtaining a cast material by supplying a molten magnesium alloy to a continuous casting apparatus provided with a movable casting mold; and   a rolling step for performing an area-reducing operation by supplying the cast material to one member selected from the group consisting of at least one roll group and at least two pairs of rolls, in the rolling step, pressure being applied to the cast material using the rolls from at least three directions in the cross section of the cast material, wherein:   the rolling step is performed immediately after the casting step as a continuous step, and   the method is performed such that structure of the magnesium-alloy material becomes any one of   a hot-rolled structure,   a mixed structure composed of a hot-rolled structure and a recrystallized structure, and   a recrystallized structure, and wherein:   in the rolling step, the rolling operation is performed by using a first pair of rolls having first rotation axes and a second pair of rolls having second rotation axes, and   the first rotation axes are perpendicular to the second rotation axes so that the first pair of rolls applies pressure to the cast material from first two directions and the second pair of rolls applies pressure to the cast material from second two directions perpendicular to the first two directions.   
     
     
         9 . A magnesium-alloy wire that is obtained through performing a drawing operation on the rolled magnesium-alloy material of  claim 8  obtained through the rolling step and that has a diameter of 5 mm or less. 
     
     
         10 . A magnesium-alloy material that:
 is produced through a method comprising:
 casting step for obtaining a cast material by supplying a molten magnesium alloy to a continuous casting apparatus provided with a movable casting mold; and 
 a rolling step for performing an area-reducing operation by supplying the cast material to one member selected from the group consisting of at least one roll group and at least two pairs of rolls, in the rolling step, pressure being applied to the cast material using the rolls from at least three directions in the cross section of the cast material, wherein: 
 the rolling step is performed immediately after the casting step as a continuous step, and 
 in the rolling step, the rolling operation is performed by using a first pair of rolls having first rotation axes and a second pair of rolls having second rotation axes, and 
 the first rotation axes are perpendicular to the second rotation axes so that the first pair of rolls applies pressure to the cast material from first two directions and the second pair of rolls applies pressure to the cast material from second two directions perpendicular to the first two directions; 
   has a crystal structure composed of any one of:
 a hot-rolled structure; 
 a hot-rolled structure and a recrystallized structure; and 
 a recrystallized structure; and 
   contains 0.002 to 5.0 wt. % Ca and the remainder being composed of any of:
 Mg and impurities; 
 0.1 to 12 wt. % Al, and Mg and impurities; 
 0.1 to 12 wt. % Al; at least one constituent selected from the group consisting of 0.1 to 2.0 wt. % Mn, 0.1 to 5.0 wt. % Zn, and 0.1 to 5.0 wt. % Si; and Mg and impurities; and 
 0.1 to 10 wt. % Zn, 0.1 to 2.0 wt. % Zr, and Mg and impurities. 
   
     
     
         11 . The magnesium-alloy material as defined by  claim 10 , the material having a tensile strength of 200 MPa or more. 
     
     
         12 . A magnesium-alloy material that:
 is produced through a method comprising:
 casting step for obtaining a cast material by supplying a molten magnesium alloy to a continuous casting apparatus provided with a movable casting mold; and 
 a rolling step for performing an area-reducing operation by supplying the cast material to one member selected from the group consisting of at least one roll group and at least two pairs of rolls, in the rolling step, pressure being applied to the cast material using the rolls from at least three directions in the cross section of the cast material, wherein: 
 the rolling step is performed immediately after the casting step as a continuous step, and 
 in the rolling step, the rolling operation is performed by using a first pair of rolls having first rotation axes and a second pair of rolls having second rotation axes, and 
 the first rotation axes are perpendicular to the second rotation axes so that the first pair of rolls applies pressure to the cast material from first two directions and the second pair of rolls applies pressure to the cast material from second two directions perpendicular to the first two directions; 
   has a crystal structure composed of any one of:
 a hot-rolled structure; 
 a hot-rolled structure and a recrystallized structure; and 
 a recrystallized structure; and 
   contains an added element other than Mg with a content of at least 5 wt. % and at most 15 wt. % and the remainder composed of Mg and impurities.   
     
     
         13 . The magnesium-alloy material as defined by  claim 12 , wherein the added element other than Mg is at least one element selected from the group consisting of Al, Mn, Zn, Si, Zr, and Y. 
     
     
         14 . The magnesium-alloy material as defined by  claim 12 , wherein the content of the added element other Mg is at least 9 wt. % and at most 15 wt. %. 
     
     
         15 . The magnesium-alloy material as defined by  claim 12 , wherein the magnesium alloy further contains 0.002 to 5.0 wt. % Ca. 
     
     
         16 . The magnesium-alloy material as defined by  claim 8 , wherein average crystal grain diameter of the magnesium-alloy material is 5 to 20 μm. 
     
     
         17 . The magnesium-alloy material as defined by  claim 8 , wherein a size of precipitated-out substance is at most 10 μm. 
     
     
         18 . The magnesium-alloy material as defined by  claim 10 , wherein average crystal grain diameter of the magnesium-alloy material is 5 to 20 μm. 
     
     
         19 . The magnesium-alloy material as defined by  claim 10 , wherein a size of precipitated-out substance is at most 10 μm. 
     
     
         20 . The magnesium-alloy material as defined by  claim 12 , wherein average crystal grain diameter of the magnesium-alloy material is 5 to 20 μm. 
     
     
         21 . The magnesium-alloy material as defined by  claim 12 , wherein a size of precipitated-out substance is at most 10 μm.