Method for producing a heat exchange tube

Abstract

A method for producing a heat exchange tube having an inner turbulence insert for a heat exchanger may include providing an austenitic heat exchange tube and the turbulence insert. The method may also include inserting the turbulence insert into the austenitic heat exchange tube, brazing the turbulence insert and the austenitic heat exchange tube via induction brazing, and pressing the austenitic heat exchange tube onto the turbulence insert at least one of during the brazing and after the brazing.

1 . A method for producing a heat exchange tube having an inner turbulence insert for a heat exchanger, comprising:
 providing an austenitic heat exchange tube and the turbulence insert;   inserting the turbulence insert into the austenitic heat exchange tube;   brazing the turbulence insert and the austenitic heat exchange tube via induction brazing; and   pressing the austenitic heat exchange tube onto the turbulence insert at least one of during the brazing and after the brazing.   
     
     
         2 . The method according to  claim 1 , further comprising applying a brazing alloy as at least one of a brazing foil and a brazing paste onto at least one of an inner side of the austenitic heat exchange tube and the turbulence insert. 
     
     
         3 . The method according to  claim 1 , wherein the pressing of the austenitic heat exchange tube onto the turbulence insert is via at least one roller pair. 
     
     
         4 . The method according to  claim 1 , wherein at least one of:
 the austenitic heat exchange tube is composed of an austenitic stainless steel; and   the turbulence insert is composed of at least one of a ferritic stainless steel and an austenitic stainless steel.   
     
     
         5 . The method according to  claim 1 , wherein the brazing takes place subject to a protection-gas atmosphere. 
     
     
         6 . A heat exchanger comprising at least one heat exchange tube affixed in an associated tube sheet via a laser-weld connection, the at least one heat exchange tube being produced by:
 providing an austenitic heat exchange tube and a turbulence insert;   inserting the turbulence insert into the austenitic heat exchange tube;   brazing the turbulence insert and the austenitic heat exchange tube via induction brazing; and   pressing the austenitic heat exchange tube onto the turbulence insert at least one of during the brazing and after the brazing.   
     
     
         7 . The heat exchanger according to  claim 6 , wherein a wall thickness of the at least one heat exchange tube is smaller than 0.5 mm. 
     
     
         8 . The heat exchanger according to  claim 6 , wherein the at least one heat exchange tube is a shaped and laser-welded steel strip. 
     
     
         9 . The heat exchanger according to  claim 6 , wherein the at least one heat exchange tube includes at least one of at least one longitudinal bead and at least one transverse bead. 
     
     
         10 . The heat exchanger according to  claim 6 , wherein at least one of:
 a longitudinal-end region of the at least one heat exchange tube laser-welded to the associated tube sheet is free of a brazing alloy; and   the heat exchanger is designed as an exhaust-gas heat exchanger.   
     
     
         11 . The heat exchanger according to  claim 6 , wherein a longitudinal-end region of the at least one heat exchange tube laser-welded to the associated tube sheet is free of a brazing alloy. 
     
     
         12 . The heat exchanger according to  claim 7 , wherein the at least one heat exchange tube includes at least one of at least one longitudinal bead and at least one transverse bead. 
     
     
         13 . The method according to  claim 1 , wherein the at least one of during the brazing and after the brazing includes both during the brazing and after the brazing. 
     
     
         14 . The method according to  claim 1 , wherein the austenitic heat exchange tube is composed of an austenitic stainless steel. 
     
     
         15 . The method according to  claim 1 , wherein the turbulence insert is composed of a ferritic stainless steel. 
     
     
         16 . The method according to  claim 1 , wherein the turbulence insert is composed of an austenitic stainless steel. 
     
     
         17 . A method for producing a heat exchange tube having an inner turbulence insert for a heat exchanger, comprising:
 providing an austenitic heat exchange tube and the turbulence insert;   inserting the turbulence insert into the austenitic heat exchange tube;   brazing the turbulence insert and the austenitic heat exchange tube subject to a protection-gas atmosphere via induction brazing;   pressing the austenitic heat exchange tube onto the turbulence insert via at least one roller pair at least one of during the brazing and after the brazing.   
     
     
         18 . The method according to  claim 17 , further comprising applying a brazing alloy onto at least one of an inner side of the austenitic heat exchange tube and the turbulence insert. 
     
     
         19 . The method according to  claim 18 , wherein the brazing alloy is a brazing foil. 
     
     
         20 . The method according to  claim 18 , wherein the brazing alloy is a brazing paste.