Free-bending forming apparatus for tubular component made of difficult-to-deform material using differential temperatures and method thereof

Abstract

A free-bending forming apparatus for a tubular component using differential temperatures and a method thereof are disclosed. The apparatus includes an isothermal heating device and a heating device for the differential temperatures. The isothermal heating device is configured to preheat an inside and an outside of a bending section of the tubular component to a predetermined temperature to form a preheated bending section before bending and forming. The heating device for the differential temperatures is configured to heat the inside and the outside of the preheated bending section of the tubular component respectively to different temperatures, and the temperature at the outside is higher than that at the inside. The heating device for the differential temperatures is provided between a pressing device and a guiding mechanism, and the isothermal heating device is provided between the pressing device and the heating device for the differential temperatures.

What is claimed is: 
     
         1 . A free-bending forming apparatus for a tubular component using differential temperatures, the apparatus comprising:
 a spherical bearing;   a bending die;   a guiding mechanism;   at least one infrared thermometer;   a pressing device;   a feeding device;   an isothermal heating device;   a heating device for the differential temperatures;   wherein the heating device for the differential temperatures is disposed between the pressing device and the guiding mechanism; and   wherein the isothermal heating device is disposed between the pressing device and the heating device for the differential temperatures.   
     
     
         2 . The free-bending forming apparatus of  claim 1 , wherein the heating device for the differential temperatures further comprises an annular sleeve, whereby the annular sleeve is able to be sleeved outside the tubular component to transfer heat from at least one heating resistor to the tubular component, and wherein the at least one heating resistor is disposed within the annular sleeve in a predetermined arrangement, thereby allowing the at least one heating resistor to control a respective temperature. 
     
     
         3 . The free-bending forming apparatus of  claim 2 , wherein a second forming temperature at an inside of a bending section comprises a range of 200° C. to 700° C., and a first forming temperature at an outside of the bending section comprises a range of 250° C. to 700° C., whereby each of the infrared thermometers is disposed in a predetermined arraignment at a corresponding heating resistor, thereby measuring in real-time a temperature of at least a portion of the tubular component corresponding to the at least one heating resistor. 
     
     
         4 . The free-bending forming apparatus of  claim 3 , further comprising a temperature control system, the temperature control system being configured to collect at least one feeding speed of the tubular component in real-time, whereby the temperature control system comprises at least one heating rate according to the at least one feeding speed of the tubular component collected, thereby guaranteeing that the temperature measured by each of the infrared thermometer is consistent with the first forming temperature or the second forming temperature. 
     
     
         5 . The free-bending forming apparatus of  claim 1 , wherein the bending die and the pressing device are made of materials selected from the group consisting of materials comprising oxidation resistance, strength at a predetermined temperature, corrosion resistance at a predetermined temperature, and a combination of thereof, and wherein a ceramic liner is configured to be embedded in the bending die and in direct contact with the tubular component, whereby the ceramic liner is made of a ceramic material. 
     
     
         6 . The free-bending forming apparatus of  claim 5 , wherein the ceramic liner comprises zirconium oxide. 
     
     
         7 . A method for free-bending a tubular component using differential temperatures, the method comprising:
 preheating, via a at least one heating device of a free-bending forming apparatus, the tubular component to enable an inside and an outside of a preheated bending section of the tubular component to have a same initial temperature; and   heating, via the at least one heating device of the free-bending forming apparatus, the inside and the outside, respectively, of the preheated bending section of the tubular component to at least one different forming temperature according to a deflection direction and a bending angle of the bending die, wherein a first forming temperature of the different forming temperatures which is at the outside of the bending section is higher than a second forming temperature of the different forming temperatures which is at the inside of the bending section.   
     
     
         8 . The method of  claim 7 , wherein the at least one heating device for the differential temperatures comprises an annular sleeve, the annular sleeve being able to be sleeved outside the tubular component to transfer heat from a plurality of heating resistors to the tubular component, and wherein at least one heating resistor is disposed within the annular sleeve in a predetermined arraignment, whereby the at least one heating resistor is able to control a respective temperature independently. 
     
     
         9 . The method of  claim 7 , wherein the second forming temperature at the inside of the bending section is in a range of 200° C. to 700° C., and the first forming temperature at the outside of the bending section is in a range of 250° C. to 700° C. 
     
     
         10 . The method of  claim 9 , wherein at least one infrared thermometer is disposed about the at least one heating resistor in an arrangement corresponding the predetermined arraignment of the at least one heating resistor, whereby a temperature of a portion of the tubular component which is corresponding to the corresponding one of the heating resistors is measured in real time. 
     
     
         11 . The method of  claim 10 , wherein the free-bending forming apparatus further comprises a temperature control system, the temperature control system being configured to collect at least one feeding speed of the tubular component in real time, and to have at least one different heating rate according to the at least one feeding speed of the tubular component, thereby guaranteeing that the temperature measured by each of the infrared thermometer is consistent with the first forming temperature or the second forming temperature. 
     
     
         12 . The method of  claim 11 , wherein the free-bending forming apparatus further comprises at least one bending die and at least one pressing device, whereby the at least one bending die and the at least one pressing device comprise materials selected from the group consisting of materials which have oxidation resistance, strength resistance at a predetermined temperature, corrosion resistance at a predetermined temperature, and a combination of thereof. 
     
     
         13 . The method of  claim 12 . Wherein the free-bending forming apparatus further comprises a ceramic liner, the ceramic liner being embedded in the bending die and in direct contact with the tubular component, is made of a ceramic material. 
     
     
         14 . The method of  claim 13 , wherein the ceramic liner is made of zirconium oxide. 
     
     
         15 . The method of  claim 7 , wherein the free-bending forming apparatus further comprises at least one infrared thermometer disposed about the at least one heating resistor in an arrangement corresponding the predetermined arraignment of the at least one heating resistor, whereby a temperature of a portion of the tubular component which is corresponding to the corresponding one of the heating resistors is measured in real time. 
     
     
         16 . The method of  claim 7 , wherein the free-bending forming apparatus further comprises a temperature control system configured to collect at least one feeding speed of the tubular component in real time, and to have at least one different heating rate according to the feeding speed of the tubular component, thereby guaranteeing that the temperature measured by each of the infrared thermometers is consistent with the first forming temperature or the second forming temperature. 
     
     
         17 . The method of  claim 7 , further comprising the steps of:
 inputting parameters of a forming process of the tubular component and the forming temperatures required by the bending section of the tubular component to a free-bending control system for three-dimensional free-bending;   feeding the tubular component into a heating zone by at least one feeding device, holding the tubular component, via at least one pressing device of the free-bending forming apparatus, and ensuring the stability of the tubular component in an X direction, a Y direction, and a Z direction so as to ensure that the tubular component is free of displacement and rotation during heating of the tubular component;   injecting at least one lubricant into an oil groove disposed within at least one guiding mechanism for the free-bending forming apparatus, wherein the guiding mechanism comprises at least one oil injection hole;   preheating the tubular component by at least one isothermal heating device to enable the inside and the outside of the tubular component to have the same initial temperature lower than the forming temperatures;   starting the bending die;   heating each of different zones of the bending section of the tubular component to a corresponding one of the forming temperatures by the at least one heating device for the differential temperatures according to the deflection direction and the bending angle of the bending die, thereby enabling the inside and the outside of the bending section of the tubular component have respective different temperatures; and   transferring heat to the tubular component by contacting the at least one bending die to the tubular component, utilizing the differential temperatures.