Large diameter tungsten-lanthana rod

Abstract

A large-diameter tungsten-lanthana rod having an elongated grain structure substantially parallel to the longitudinal axis of the rod is described. The large diameter rod is produced by rolling at a temperature greater than 1400° C. and less than 1700° C. to achieve at least about a 40% reduction in cross-sectional area. The high strength of the longitudinally elongated grain structure is desirable for applications such as rocket nozzles.

1 - 7 . (canceled).  
     
     
         8 . A method of making a large-diameter tungsten-lanthana rod comprising rolling a tungsten-lanthana rod at a temperature greater than 1400° C. and less than 1700° C. until at least about a 40% reduction in the cross-sectional area of the rod is achieved.  
     
     
         9 . The method of  claim 8  wherein the rolling is performed by multiple passes.  
     
     
         10 . The method of  claim 8  wherein at least about a 70% reduction in cross-sectional area is achieved.  
     
     
         11 . The method of  claim 8  wherein the rod after rolling has a UTS of from about 70 to about 85 ksi, a YS of from about 60 to about 80 ksi and a hardness of from about 40 to about 43 Rockwell C.  
     
     
         12 . The method of  claim 11  wherein the tungsten-lanthana rod contains from 0.3 to 2.5 weight percent lanthana.  
     
     
         13 . The method of  claim 8  wherein the rod is stress relieved at a point between 25 and 45% reduction in cross-sectional area.  
     
     
         14 . The method of  claim 8  wherein the rod is stress relieved after rolling.