Magnesium-based alloy wire and method of its manufacture

Abstract

Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

1 . A method of manufacturing magnesium-based alloy wire, characterized in being provided with: 
 a step of preparing, as a raw-material parent metal, a magnesium-based alloy composed of any of the chemical components in (A) through (E) below:    (A) magnesium-based alloy parent metals containing, in mass %: 0.1 to 12.0% Al, and 0.1 to 1.0% Mn;    (B) magnesium-based alloy parent metals containing, in mass %: 0.1 to 12.0% Al, and 0.1 to 1.0% Mn; and furthermore containing one or more elements selected from 0.5 to 2.0% Zn, and 0.3 to 2.0% Si;    (C) magnesium-based alloy parent metals containing, in mass %: 1.0 to 10.0% Zn, and 0.4 to 2.0% Zr;    (D) magnesium-based alloy parent metals containing, in mass %: 1.0 to 10.0% Zn, and 0.4 to 2.0% Zr; and furthermore containing 0.5 to 2.0% Mn; and    (E) magnesium-based alloy parent metals containing, in mass %: 1.0 to 10.0% Zn, and 1.0 to 3.0% rare-earth element(s); and    a processing step of drawing the raw-material parent metal to work it into wire form.    
     
     
         2 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that the working temperature in the drawing process is 50° C. or more and 200° C. or less.  
     
     
         3 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that cross-sectional reduction rate in one cycle of the drawing process is 10% or more.  
     
     
         4 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that total cross-sectional reduction rate in the drawing process is 15% or more.  
     
     
         5 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that wire speed in the drawing process is 1 m/min or more.  
     
     
         6 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that speed of temperature elevation to the drawing process temperature is 1° C./sec to 100° C./sec.  
     
     
         7 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that the drawing process is carried out with a wire die or roller dies.  
     
     
         8 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that the drawing process is carried out in multiple stages utilizing a plurality of wire dies or roller dies.  
     
     
         9 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that after the drawing process has been performed, the obtained wire-form article is heated at a temperature of 100° C. or more and 300° C. or less.  
     
     
         10 . A magnesium-based-alloy wire manufacturing method as set forth in  claim 1 , characterized in that the drawing process is carried out at less than 50° C.