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Do you remember the correct way of welding?

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Copper pipe in our actual life is not rare, but our understanding of it may only stay in the use of copper pipe welding process method introduction rules know very little.


In some industries where nonferrous materials such as copper and aluminum are used,


The welding of pipes is a key part in the process of manufacture, installation and maintenance.


It not only affects the appearance, but also affects the normal operation of the system.


Today, xiaobian will explore the right way to open welding with you


I. Welding methods of similar materials


(1) Steel to steel welding


Copper and steel welding can be made of brass strip solder with appropriate flux


When welding, heat the solder to a certain temperature and insert it into the flux.


Melt flux and attach to solder.


However, it is important to note that after welding, the residual flux near the welding mouth must be cleaned to prevent corrosion


(2) Copper to copper welding


Copper to copper brazing should be done using phosphor copper solders or low silver content phosphor copper solders such as 2% or 5% silver-based solders.


This solder is not only cheap, but also good liquid;


The filler and wetting process is used and no flux is required


Ii. Welding methods of different materials


(1) Copper and steel or copper and aluminum welding


Copper and steel or copper and aluminum welding can be selected silver copper solder and appropriate flux


After welding, the residual flux near the welding mouth should be cleaned with hot water or water vapor to prevent corrosion


Note: in the use of flux, it is best to dilute the alcohol into a paste, coated on the surface of the welding;


During welding, alcohol evaporates rapidly to form a smooth film that is not easily lost, thus avoiding the risk of water immersion in the system.


(2) Welding of copper and iron


Copper and iron welding, the choice of phosphor copper solder or brass strip solder,


However, a suitable flux, such as borax, boric acid or a mixture of boric acid, should also be used


Welding gun size and flame temperature


All of them affect the welding effect


Should pay attention to the scientific choice of use.


1. Flame regulation


Before ignition, the valves of oxygen cylinders and acetylene cylinders should be opened respectively according to the operating rules, so that the low pressure oxygen meter indicates around 0.05mpa.Then slightly open the oxygen valve of the welding gun and, at the same time, quickly ignite from the back of the welding nozzle.(Note: it is not allowed to ignite in the front of the welding nozzle, so as to avoid the flame-thrower) After lighting the welding gun, the two valves can be adjusted. The proportion of oxygen and acetylene entering the welding gun mixture is different, so as to get different flames.


The preparatory work is done, this is the first step.


When welding, we must pay more attention to make every welding perfect.


1. Corresponding protection measures shall be taken for the parts that are changeable and damaged under high temperature.


2. During welding, when copper pipe is annealed after welding, the annealing temperature shall not be lower than 300℃


3. After welding, clean oxide and welding slag in the pipe with dry nitrogen after cooling.


4. During welding, preheat the welding parts must be carried out.


When the copper pipe is heated to purple, remove the flame and put the solder near the welding mouth, so that the solder melts and flows into the welded copper parts. The temperature after heating can be reflected by the color of the temperature.


5. During welding, the gas welding flame shall not directly heat the electrode


2. Flame types and Characteristics:


When welding, the size of the flame can be controlled through two needle valve adjustment, flame adjustment according to the oxygen, acetylene gas volume ratio can be divided into: carbonization flame, neutral flame and oxide flame.


(1) Carbonization flame characteristics


The volume ratio of oxygen and acetylene gas is less than 1, slightly hypoxia, easy to bring carbon particles into metal and affect solder flow, black smoke, the temperature is about 2700, can be used for pipeline baking, etc.


(2) Characteristics of neutral flame


The size of flame core depends on the composition, consumption and flow rate of combustion gas, and the diameter of nozzle hole determines the flame core.The mixture flow rate determines the length of the flame core.


(3) Characteristics of oxide flame


The flame core is conical, the length is obviously shortened, the outline is not clear, the color is dim, the outer flame is also shortened, the flame is blue, the flame burns with a sound.The temperature of the oxide flame is higher than that of the neutral flame, suitable for welding brass pipe fitting.


The properties of the flame are selected according to the type of metal being welded and its properties



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