Tunsten wire, cathode heater, and filament for vibration service lamp

Abstract

A tungsten wire containing 1 to 10% by mass of rhenium has a point which indicates a 2% elongation within a quadrangle formed by joining points with straight lines, where the values of x and y are point ( 20, 75 ), point ( 20, 87 ), point ( 90, 75 ), and point ( 90, 58 ), in this order, wherein the wire diameter of the aforementioned tungsten wire is represented by x μm, and the elongation of the tungsten wire is 2% after electrically heating with an electrical current which is a ratio of y % to the fusion current (FC) at the wire diameter x μm, and wherein a semi-logarithmic system of coordinates is expressed by a horizontal axis using a logarithmic scale of the aforementioned wire diameter x and a vertical axis using a normal scale of ratio y to the fusion current. According to the above-described configuration, a tungsten wire having a great elongation even under conditions of high temperature can be provided, and the tungsten wire can exhibit an excellent durability when used as component material for constituting cathode heaters and so forth, and the tungsten wire can be manufactured efficiently.

1 . A tungsten wire containing 1 to 10% by mass of rhenium; said tungsten wire having a point which indicates a 2% elongation within a quadrangle formed by joining points with straight lines, where the values of x and y are point ( 20 ,  75 ), point ( 20 ,  87 ), point ( 90 ,  75 ), and point ( 90 ,  58 ), in this order, wherein the wire diameter of said tungsten wire is represented by x μm, and the elongation of the tungsten wire is 2% after electrically heating with an electrical current which is a ratio of y % to the fusion current (FC) at said wire diameter x μm, and wherein a semi-logarithmic system of coordinates is expressed by means of a horizontal axis using a logarithmic scale of said wire diameter x and a vertical axis using a normal scale of ratio y to said fusion current.  
     
     
         2 . A tungsten wire containing 1 to 10% by mass of rhenium; said tungsten wire having a point which indicates a 5% elongation within a quadrangle formed by joining points with straight lines, where the values of x and y are point ( 20 ,  73 ), point ( 20 ,  83 ), point ( 90 ,  72 ), and point ( 90 ,  56 ), in this order, wherein the wire diameter of said tungsten wire is represented by x μm, and the elongation of the tungsten wire is 5% after electrically heating with an electrical current which is a ratio of y % to the fusion current (FC) at said wire diameter x μm, and wherein a semi-logarithmic system of coordinates is expressed by means of a horizontal axis using a logarithmic scale of said wire diameter x and a vertical axis using a normal scale of ratio y to said fusion current.  
     
     
         3 . A tungsten wire containing more than 10% by mass but 30% by mass or less of rhenium; said tungsten wire having a point which indicates a 2% elongation within a quadrangle formed by joining points with straight lines, where the values of x and y are point ( 20 ,  55 ), point ( 20 ,  63 ), point ( 90 ,  51 ), and point ( 90 ,  39 ), in this order, wherein the wire diameter of said tungsten wire is represented by x μm, and the elongation of the tungsten wire is 2% after electrically heating with an electrical current which is a ratio of y % to the fusion current (FC) in said wire diameter x μm, and wherein a semi-logarithmic system of coordinates is expressed by means of a horizontal axis using a logarithmic scale of said wire diameter x and a vertical axis using a normal scale of ratio y to said fusion current.  
     
     
         4 . A tungsten wire containing more than 10% by mass but 30% by mass or less of rhenium; said tungsten wire having a point which indicates a 5% elongation within a quadrangle formed by joining points with straight lines, where the values of x and y are point ( 20 ,  53 ), point ( 20 ,  60 ), point ( 90 ,  48 ), and point ( 90 ,  37 ), in that order, wherein the wire diameter of said tungsten wire is represented by x μm, and the elongation of the tungsten wire is 5% after electrically heating with an electrical current which is a ratio of y % to the fusion current (FC) at said wire diameter x μm, and wherein a semi-logarithmic system of coordinates is expressed by means of a horizontal axis using a logarithmic scale of said wire diameter x and a vertical axis using a normal scale of ratio y to said fusion current.  
     
     
         5 . A tungsten wire according to  claim 1 , wherein said tungsten wire is formed from a tungsten alloy containing 40 to 100 ppm of potassium (K).  
     
     
         6 . A cathode heater configured of said tungsten wire according to  claim 1 .  
     
     
         7 . A vibration service lamp filament configured of said tungsten wire according to  claim 1 .  
     
     
         8 . A manufacturing method of tungsten wire comprising: a process of heating and rolling a tungsten sintered body containing 1 to 30% by mass of rhenium; a process of heating and swaging the rolled sintered body after a recrystallization heating treatment; and a process of heating and wire drawing the swaged sintered body; wherein said rolling process establishes the process rate of performing a rolling operation for one heating as 40 to 75%.  
     
     
         9 . A manufacturing method of tungsten wire according to  claim 8 , said method further comprising a process of performing a heating treatment to said tungsten wire at a temperature of 2300° C. or less at a time when the diameter of the tungsten wire formed by said swaging process or wire drawing process becomes 100 μm or less.