The main techniques for welding copper and aluminum tubes include the following aspects :
Welding Processes and tools :
Use an industrial water-fuel hydrogen-oxygen machine for welding, with a special torch for hydrogen-oxygen flame 1.
Choose an air combustion torch with uniform heating, with air flow control valve and rotating device, the flame rotates out through the nozzle to ensure uniform flame 1.
Joint design and surface treatment :
The joint unilateral clearance should be controlled at 0.08 ~ 0.2mm, and the weld length is generally not more than 30mm12.
Use lye or metal cleaning solution to clean the oil and dirt at the joint welding place, and then use a scraper, coarse sandpaper, copper brush or wire brush to remove the insulation layer, but pay attention to not polished, because the solder is welded by capillary action, polishing is not good for welding.
Flame control and heating methods :
The flame should be gentle and completely covering the welding area, moving the flame up and down and left and right, centered on the connection area, to ensure even heating 1.
At the same time of heating, contact the workpiece in the connection area with the wire, and feed the wire immediately when the wire melts until the solder fills the weld 1.
Cooling method :
Remove the torch after welding and allow it to cool naturally. Avoid the flame aligning to a point for a long time and the welding temperature should not exceed 630℃ to prevent the base metal from burning out
Post-welding treatment :
After cooling, no further treatment is required, and the residue of the flux is non-corrosive and firmly attached. If necessary, physical removal can be performed, such as removal with a metal brush after immersion 1.
Advantages and disadvantages of copper and aluminum pipe welding and application scenarios :
Advantages : Better brazing process molding, tensile and shear properties and good conductivity and corrosion resistance, suitable for the connection of a variety of metal materials 3.
Disadvantages : The traditional tin hanging and melting method is not good and low strength, not suitable for high temperature working environment; Other welding methods, such as fusion welding and friction welding, are brittle and prone to cracks and pores 3.
Application scenario : Suitable for low-temperature working environments requiring good electrical conductivity and corrosion resistance 3.
Through the above techniques and methods, the welding of copper pipe and aluminum pipe can be effectively realized to ensure the welding quality and effect.