System for Extending the Life of Thin Walled Tubing and Austempered Weld Stress Relieved Thin Walled Tubing

Abstract

The present invention is directed to a method of extending the life of thin walled tubing by austempering the tubing in a controlled continuous run process involving heating, quenching, and cooling the tubing pursuant to predetermined process parameters. The invention is also directed to a process for austempering tubing having a welded seam and for relieving residual stress in the weld. The invention is further directed to the product of the above processes as well as an austempered weld stress relieved thin walled tubing and such tubing in combination with other apparatus with which it is suitable for use in the production of hydrocarbons.

1 . An apparatus for austempering a continuous run of thin walled tubing, comprising: 
 a. a heater adapted to heat a section of continuous run metallic tubing to a high temperature in excess of around 1300° F.;    a non-water based low temperature reservoir operatively in communication with the heater and adapted to accept a heated section of the metallic tubing from the heater and cool the received heated section of the metallic tubing to a first cooled temperature; and    a first cooler operatively in communication with the non-water based low temperature reservoir and adapted to accept the cooled section of metallic tubing from the non-water based low temperature reservoir and cool the section of metallic tubing to a second cooled temperature below 100° F.    
   
   
       2 . The apparatus of  claim 1 , wherein the heater is configured to accept a section of metallic tubing that has a wall thickness of less than 0.25 inches.  
   
   
       3 . The apparatus of  claim 1 , wherein the high temperature is in the range of around 1300 to around 1600° F.  
   
   
       4 . The apparatus of  claim 1 , wherein the heater comprises at least one of (i) an induction heater or (ii) a flame.  
   
   
       5 . The apparatus of  claim 1 , wherein the heater is located at least one of (i) proximate the low temperature reservoir, (ii) partially disposed within the low temperature reservoir, or (iii) totally disposed within the low temperature reservoir.  
   
   
       6 . The apparatus of  claim 1 , wherein the low temperature reservoir is a molten salt bath.  
   
   
       7 . The apparatus of  claim 1 , wherein the non-water based low temperature reservoir is adapted to reduce the temperature of the moving section of the metallic tubing as part of a continuous run process to a first low temperature in the range of 500-1000° F.  
   
   
       8 . The apparatus of  claim 1 , wherein non-water based low temperature reservoir is adapted to reduce the temperature in a time period of less than 3 seconds.  
   
   
       9 . The apparatus of  claim 1 , where the first cooler is a forced convection cooler.  
   
   
       10 . The apparatus of  claim 1 , further comprising a plurality of rollers disposed intermediate the heater, the non-water low temperature reservoir, and the first cooler.  
   
   
       11 . The apparatus of  claim 1 , further comprising a second cooler adapted to receive the moving section of the metallic tubing from the first cooler.  
   
   
       12 . The apparatus of  claim 1 , further comprising a take up reel adapted to take up a cooled moving section of the metallic tubing.