Methods for quenching metal tubes

Abstract

Improved methods for quenching a metal tube are disclosed. A method of manufacturing a metal tube generally comprises solution heat treating a metal tube at an elevated temperature, rapidly cooling the metal tube from the elevated temperature, raising the open end of the metal tube to an elevated position, and lowering the open end of the metal tube to a downward facing position, wherein the metal tube comprises an open end and an opposing closed end, wherein the immersing step comprises at least partially filling the metal tube with the cooling liquid, and developing an evolved gas inside the metal tube, wherein the raising comprises releasing at least some of the evolved gas from the metal tube via the open end, and wherein the lowering comprises draining cooling liquid from the metal tube via the open end.

What is claimed is: 
     
         1 . A method of manufacturing a metal tube comprising:
 (a) heat treating a metal tube at an elevated temperature, wherein the metal tube comprises an open end and an opposing closed end; and   (b) after the heat treating step, rapidly cooling the metal tube from the elevated temperature, wherein the rapidly cooling step comprises:
 (i) immersing the metal tube in a cooling liquid, wherein the immersing step comprises:
 (A) at least partially filling the metal tube with the cooling liquid; and 
 (B) developing an evolved gas inside the metal tube; 
 
 (ii) raising the open end of the metal tube to an elevated position, wherein the raising comprises releasing at least some of the evolved gas from the metal tube via the open end; and 
 (iii) lowering the open end of the metal tube to a downward facing position, wherein the lowering comprises draining cooling liquid from the metal tube via the open end. 
   
     
     
         2 . The method of  claim 1 , wherein the metal tube is an extruded metal tube. 
     
     
         3 . The method of  claim 1 , wherein the metal tube is a machined metal tube, a casted metal tube, a hogged metal tube, or a metal tube fabricated from multiple parts. 
     
     
         4 . The method of  claim 1 , wherein the metal tube comprises a nickel alloy, a cobalt alloy, a steel alloy, an aluminum alloy or a titanium alloy. 
     
     
         5 . The method of  claim 1 , wherein the rapidly cooling step comprises quenching. 
     
     
         6 . The method of  claim 1 , wherein the cooling liquid is a quenching liquid. 
     
     
         7 . The method of  claim 6 , wherein the quenching liquid is an aqueous liquid or an organic liquid. 
     
     
         8 . The method of  claim 7 , wherein the aqueous liquid is water, water plus carbon dioxide, or water plus a polymer. 
     
     
         9 . The method of  claim 7 , wherein the organic liquid comprises an oil or an organic aqueous polymer. 
     
     
         10 . The method of  claim 1 , wherein the elevated temperature is sufficient to place soluble constituents of the metal into a solid solution and/or to affect or prevent a phase change in the metal. 
     
     
         11 . The method of  claim 1 , wherein the raising step (b)(ii) further comprises removing the metal tube fully from the cooling liquid. 
     
     
         12 . The method of  claim 1 , wherein the immersing step (b)(i) comprises:
 (A) submerging the metal tube in the cooling liquid; and   (B) developing an evolved gas inside the metal tube.   
     
     
         13 . The method of  claim 11 , wherein the raising step (b)(ii) further comprises removing the metal tube fully from the cooling liquid. 
     
     
         14 . The method of  claim 1 , wherein the raising step comprises tilting the metal tube such that the open end of the metal tube faces upward by an angle of from 1 to 45 degrees above the horizontal axis, and wherein lowering step comprises tilting the metal tube such that the open end of the metal tube faces downward by an angle of from 1 to 45 degrees below the horizontal axis. 
     
     
         15 . The method of  claim 1 , wherein the immersing step (b)(i) comprises:
 (A) positioning the metal tube in a substantially horizontal position;   (B) at least partially filling the metal tube with the cooling liquid; and   (C) developing an evolved gas inside the metal tube.   
     
     
         16 . The method of  claim 14 , wherein the positioning step (A) comprises: positioning the metal tube in a substantially horizontal position on a tiltable device. 
     
     
         17 . The method of  claim 16 , wherein the tiltable device is a quenching table. 
     
     
         18 . The method of  claim 1 , wherein the immersing step (b)(i) comprises:
 (A) positioning the metal tube in a substantially horizontal position;   (B) submerging the metal tube in the cooling liquid; and   (C) developing an evolved gas inside the metal tube.   
     
     
         19 . The method of  claim 18 , wherein the raising step (b)(ii) further comprises removing the metal tube fully from the cooling liquid. 
     
     
         20 . A method of manufacturing a metal tube comprising:
 (a) heat treating an extruded metal tube at an elevated temperature, wherein the metal tube comprises an open end and an opposing closed end; and   (b) after the heat treating step, quenching the metal tube, wherein the quenching comprises:
 (i) positioning the metal tube on a tiltable device; 
 (ii) immersing the metal tube in a quenching liquid, wherein the immersing step comprises:
 (A) at least partially filling the metal tube with the quenching liquid; and 
 (B) developing an evolved gas inside the metal tube; 
 
 (ii) raising, with the tiltable device, the open end of the metal tube to an elevated position, wherein the raising comprises releasing at least some of the evolved gas from the metal tube via the open end; 
 (iii) removing the metal tube and the tiltable device from the quenching fluid; and 
 (iv) lowering, with the tiltable device, the open end of the metal tube to a downward facing position, wherein the lowering comprises draining cooling liquid from the metal tube via the open end.