Heat treatment method and apparatus

Abstract

The invention is a method of and apparatus for in-situ heat treatment for re-solutionizing β-phase in sensitized aluminum-magnesium alloy structures and, in particular, a method of and apparatus for in-situ heat treatment for re-solutionizing β-phase in sensitized aluminum-magnesium alloy structures comprising naval vessels. The invention also relates to a method for maximizing the absorption of radiant energy on a substrate. The invention also relates to an apparatus for securing a heat treatment device to a substrate having an irregular surface.

1 . A method of in-situ heat treatment for de-sensitizing all or predetermined portions of a sensitized 5XXX aluminum-magnesium alloy structure comprising the steps of:
 defining a treatment area within said sensitized structure;   determining a goal temperature for said treatment area;   determining a goal heat maintenance time for said treatment area;   temporarily attaching a portable heat treatment device to said treatment area;   turning said heat treatment device on and applying heat to said treatment area to achieve said goal temperature within said treatment area;   maintaining said goal temperature for said predetermined heat maintenance time;   turning said treatment device off so that it is no longer applying heat to said treatment area; and,   allowing said treatment area of said structure to air-cool back to ambient temperature.   
     
     
         2 . The method of  claim 1  wherein said defined treatment area is only a portion of the total area of said 5XXX aluminum-magnesium alloy structure and wherein boundary areas surround said defined treatment area, and further wherein said boundary areas are cooled during the heat treatment process to regulate the temperature of said boundary areas. 
     
     
         3 . The method of  claim 1  wherein said goal temperature is between 100° C. and 350° C. 
     
     
         4 . The method of  claim 1  wherein said goal heat maintenance time is 4 minutes or less. 
     
     
         5 . A method of in-situ heat treatment for de-sensitizing all or predetermined portions of a sensitized 5XXX aluminum-magnesium alloy structure comprising the steps of:
 defining a treatment area within said sensitized structure;   determining a de-sensitization degree of sensitization [DoS] target value for said treatment area;   determining a goal temperature for said treatment area;   temporarily attaching a portable heat treatment device to said treatment area, with said heat treatment device comprising a heat source and at least the sensor portion of a degree of sensitization [DoS] sensor being mounted inside the heat treatment device with said temporarily attaching step further comprising placing said DoS sensor in contact with said treatment area;   determining the starting DoS of said treatment area;   turning said heat treatment device on and applying heat to said treatment area to achieve said goal temperature within said treatment area;   monitoring the DoS of said treatment area on a predetermined schedule during said heat applying step;   turning said heat treatment device off so that it is no longer applying heat to said treatment area when the monitored DoS of said treatment area reaches the predetermined de-sensitization DoS value for said treatment area; and,   allowing said treatment area to air-cool back to ambient temperature.   
     
     
         6 . The method of  claim 5  wherein said heat treatment device further comprises a feedback control means which means controls said DoS monitoring and which feedback control means further comprises a means to turn said heat treatment device on or off in accord with the value of said DoS monitoring. 
     
     
         7 . A device for in-situ heat treatment to de-sensitize a sensitized 5XXX aluminum-magnesium alloy structure comprising:
 a heat source;   a prism-shaped, shroud containing said heat source with said shroud having an open bottom and a closed top;   a thermal dam mounted to and surrounding said open bottom of said shroud.   
     
     
         8 . The device of  claim 7  wherein at least one handle is mounted to said thermal dam. 
     
     
         9 . The device of  claim 7  wherein said thermal dam is water-cooled. 
     
     
         10 . The device of  claim 9  further comprising water inlet and outlet means on said thermal dam. 
     
     
         11 . The device of  claim 7  wherein said thermal dam is made of aluminum. 
     
     
         12 . The device of  claim 7  wherein said thermal dam is provided with at least one vortex tube air cooler with said vortex tube air cooler further comprising a compressed air inlet, a cold air outlet and a hot air exhaust. 
     
     
         13 . The device of  claim 12  wherein said hot air exhaust of said at least one vortex tube air cooler is channeled inside the shroud to aid in heating said structure. 
     
     
         14 . The device of  claim 7  wherein said heat source comprises at least one radiant wire heating coil. 
     
     
         15 . The device of  claim 7  wherein said heat source comprises at least one radiant heater. 
     
     
         16 . The device of  claim 7  further comprising at least two, independently adjustable mounting means secured to said thermal dam which means will secure said in-situ heat treatment device to a substrate of indefinite size. 
     
     
         17 . The device of  claim 16  wherein each of said at least two independently adjustable mounting means further comprises a base mount secured to said thermal dam and an adjustment screw mount removably mounted to said base mount. 
     
     
         18 . The device of  claim 17  wherein each of said at least two independently adjustable mounting means further comprises a longitudinal, threaded adjustment screw movably mounted in said adjustment screw mount. 
     
     
         19 . The device of  claim 18  wherein each of said at least two independently adjustable mounting means further comprises an adjustment nut threaded onto said adjustment screw and retained within said adjustment screw mount such that turning said adjustment nut in one direction moves said adjustment screw in one longitudinal direction and turning said adjustment nut in the other direction moves said adjustment screw in the opposite longitudinal direction. 
     
     
         20 . The apparatus of  claim 18  wherein each said adjustment screw mount has a proximal side and a distal side with each said adjustment screw being loosely received in a through-bore in said distal side of said adjustment screw mount, with said through-bore being interrupted by a transverse slot;
 a threaded adjustment nut rotatably mounted in said transverse slot in such a manner that it can be manually rotated by an operator; and, 
 each said adjustment screw being threaded through the adjustment nut mounted in said transverse slot wherein rotation of said adjustment nut in one direction causes each said adjustment screw to move up through said through-bore and wherein rotation of said adjustment screw in the other direction causes each said adjustment screw to move downwardly through said through-bore. 
 
     
     
         21 . The device of  claim 16  wherein said at least two, independently adjustable mounting means further comprise at least one leg base mount secured to said thermal dam with each leg base mount having a proximal side and a distal side;
 an attachment arm mounted generally perpendicular to the distal side of each leg base mount; 
 means permitting said attachment arm to be moved along said leg base mount in a first direction perpendicular to said attachment arm; 
 said means also permitting said attachment arm to be moved in a second direction perpendicular to said attachment arm and in opposition to said first direction; 
 a leg mounted generally perpendicular to each said attachment arm, with said leg comprising first and second segments; and, 
 joining means joining said first and second leg segments, said joining means further comprising a locking universal joint to permit the angle between said first and said second leg segments to be widely varied, and to lock said segments in position when said angle has been set. 
 
     
     
         22 . The device of  claim 21  wherein said second leg segment carries a suction cup means at the end of said leg segment remote from said joining means. 
     
     
         23 . The device of  claim 22  wherein said suction cup further comprises a bellows-type pneumatic suction cup. 
     
     
         24 . A method of in-situ heat treatment for de-sensitizing a predetermined portion of a 5XXX aluminum-magnesium alloy structure which predetermined portion is sensitized and which predetermined portion has at least one non-sensitized boundary area(s) bordering upon said sensitized predetermined portion, without adversely affecting said at least one non-sensitized boundary area(s) surrounding said predetermined portion, and without using any external cooling device to cool said non-sensitized boundary areas, comprising the steps of:
 determining a de-sensitization degree of sensitization [DoS] target value for said predetermined portion;   determining a goal temperature for said predetermined portion;   determining a maximum allowable temperature for said at least one non-sensitized boundary area(s);   providing a portable, point source heat treatment device, with said portable, point source heat treatment device comprising a heat source which can be operated intermittently and providing an associated control means to operate said heat source in an intermittent manner;   temporarily attaching said portable, point source heat treatment device to said structure such that said point source heat treatment device is placed over said predetermined portion and can apply heat to the part of said predetermined portion which is immediately under said point source heat treatment device;   providing a degree of sensitization [DoS] sensor comprising a sensor probe and an electronics and control package;   temporarily attaching at least the sensor probe of said DoS sensor to said predetermined portion;   using said DoS sensor to determine the starting DoS of said predetermined portion;   turning said point source heat treatment device on and applying heat to said part of said predetermined portion immediately under said point source heat treatment device to achieve and maintain said predetermined goal temperature within said part of said predetermined portion immediately below said point source heat treatment device;   monitoring the DoS of said predetermined portion on a predetermined schedule during said heat applying step;   turning said point source heat treatment device off so that it is no longer applying heat to said predetermined portion when the monitored DoS of said predetermined portion reaches the predetermined de-sensitization DoS value for said predetermined portion; and,   allowing said predetermined portion to air-cool back to ambient temperature.   
     
     
         25 . A method of in-situ heat treatment for de-sensitizing a predetermined portion of a 5XXX aluminum-magnesium alloy structure which predetermined portion is sensitized and which predetermined portion has at least one non-sensitized boundary area(s) bordering upon said sensitized predetermined portion, without adversely affecting said at least one non-sensitized boundary area(s) surrounding said predetermined portion, and without using any external cooling device to cool said non-sensitized boundary areas, comprising the steps of:
 determining a goal temperature for said predetermined portion;   determining a goal heat maintenance time for said predetermined area;   providing a portable, point source heat treatment device, with said portable, point source heat treatment device comprising a heat source which can be operated intermittently and providing an associated control means to operate said heat source in an intermittent manner;   temporarily attaching said portable, point source heat treatment device to said structure such that said point source heat treatment device is placed over said predetermined portion and can apply heat to the part of said predetermined portion which is immediately under said point source heat treatment device;   turning said point source heat treatment device on and applying heat to said part of said predetermined portion immediately under said point source heat treatment device to achieve said goal temperature;   maintaining said predetermined goal temperature within said part of said predetermined portion immediately below said point source heat treatment device for the predetermined goal heat maintenance time;   turning said point source heat treatment device off so that it is no longer applying heat to said predetermined portion; and,   allowing said predetermined portion to air-cool back to ambient temperature.   
     
     
         26 . A method of heat treating a substrate comprising;
 providing a substrate to be heat treated having a known reflectance-radiation wavelength spectral profile with a pre-determined minimum reflectance wavelength range;   providing a radiant energy emitter which can emit radiant energy over a wide range of wavelengths and, in particular, can provide radiant energy in the pre-determined minimum reflectance wavelength range of the substrate;   directing radiant energy onto a surface of the substrate by causing the radiant energy emitter to emit radiant energy in the pre-determined minimum reflectance wavelength range of the substrate; and,   thus, maximizing the heat transfer between the radiant energy emitter and the substrate.   
     
     
         27 . A method of heat treating a substrate comprising;
 providing a substrate to be heat treated;   providing a radiant energy emitter which can emit radiant energy over a pre-determined range of wavelengths;   coating the substrate with a coating which will increase the radiant energy absorption of the substrate in the pre-determined range of wavelengths emitted by the radiant energy emitter,   directing radiant energy onto a surface of the substrate by causing the radiant energy emitter to emit radiant energy in the pre-determined range of wavelengths; and, thus, maximizing the heat transfer between the radiant energy emitter and the substrate.   
     
     
         28 . A method of heat treating a substrate comprising:
 providing a substrate to be heat treated with said substrate having a pre-determined treatment surface;   providing a radiant energy emitter which can emit radiant energy over a pre-determined range of wavelengths;   treating the treatment surface of said substrate in such a way so as to increase the radiant energy absorption of the treatment surface of said substrate in the pre-determined range of wavelengths emitted by the radiant energy emitter;   directing radiant energy onto said treatment surface of said substrate by causing said radiant energy emitter to emit radiant energy in the pre-determined range of wavelengths; and,   thus, maximizing the heat transfer between the radiant energy emitter and the substrate.   
     
     
         29 . The method of  claim 28  wherein said treating step further comprises sanding said pre-determined treatment surface of said substrate. 
     
     
         30 . The method of  claim 28  wherein said treating step further comprises polishing said pre-determined treatment surface of said substrate. 
     
     
         31 . The method of  claim 28  wherein said treating step further comprises coating said pre-determined treatment surface of said substrate with a coating which coating has a high radiant energy absorption in the pre-determined wavelength range of wavelengths emitted by the radiant energy emitter.