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1 2 tube od brass flared tube inverted male elbow

author:MF manufacturerstime:2022-03-15 10:13:08

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first,Must know the necessary tools and materials for copper pipe welding。

①Phosphor copper electrode;

②Fuel is liquefied gas(gas、natural gas、Butane etc.);

③Oxygen;

④torch。


1 2 tube od brass flared tube inverted male elbow

(1 2 tube od brass flared tube inverted male elbow)

one、Selection of Solder to Use

The pipe fittings of refrigeration and air conditioning are mostly made of copper(purple)pipe,Commonly used solder types are copper phosphorus solder、silver copper solder、Copper zinc solder, etc.。When welding, according to the characteristics of the pipe material,Correct selection of solder and skilled operation,to ensure the quality of welding。

Welding of similar materials:

Brazing of copper to copper: Optional phosphor copper solder or copper phosphor solder with low silver content,This solder is cheaper,and good melt,Using a caulking and wetting process,No solder required。

Welding of steel to steel: Optional brass bar solder with appropriate flux,when welding,Heat the solder to a certain temperature and insert it in the flux,Let the flux melt and adhere to the solder,But after soldering, the residual flux near the solder joint must be brushed clean,to prevent corrosion。

Welding of different materials:

(1 2 tube od brass flared tube inverted male elbow)Welding of copper to steel or copper to aluminum: Optional silver copper solder and appropriate flux,After welding, the residual flux near the welding joint must be cleaned with hot water or steam.,prevent corrosion。When using flux, it is best to dilute it with alcohol to make a paste,Apply to the weld surface,During welding, alcohol evaporates quickly to form a smooth film that is not easy to run off,At the same time, it also avoids the danger of water immersion in the refrigeration system。

Welding of copper and iron: Optional phosphor bronze solder or brass bar solder,However, it is necessary to use the corresponding flux,such as borax、Boric acid or mixed flux of boric acid


1 2 tube od brass flared tube inverted male elbow


two、The specific operation of welding

Pair welding of different materials、The torch size and flame temperature required are different for different pipe diameters,The size of the flame during welding can be controlled and adjusted by two needle valves,The adjustment of the flame is based on the oxygen、The volume ratio of acetylene gas can be divided into carbonization flame、Neutral and oxidizing flames three。

The characteristic is that the volume ratio of oxygen to acetylene is less than1,slightly hypoxia,It is easy to bring carbon particles into the metal and affect the solder flow,black smoke,temperature is about2700℃about,Can be used for baking pipes, etc.。


1 2 tube od brass flared tube inverted male elbow


neutral flame: Its characteristic is that the size of the flame core depends on the composition of the combustion gas、consumption and flow rate,The diameter of the torch nozzle hole determines the diameter of the flame core,The flow rate of the mixture,determines the length of the flame core,flame fraction of neutral flame3Floor,)The flame core is tapered,white and bright,Internal flame is blue-white,The outer flame gradually changes from lavender to orange and blue from the inside out,temperature is about3000~3500℃about,The volume ratio of oxygen to acetylene gas is1:1.2。Neutral flame is often used in the welding of pipe fittings for refrigeration and air conditioning。


1 2 tube od brass flared tube inverted male elbow


Oxidizing flame: Its characteristic is that the flame core is conical,significantly shortened in length,outline is not clear,dull color,Outer flame is also shortened,flame is blue,Fire burning with noise,The noise depends on the oxygen pressure,The temperature of the oxidizing flame is higher than that of the neutral flame,Fitting welding for brass。The nature of the flame is based on being welded。


1 2 tube od brass flared tube inverted male elbow


three、flame regulation

Before igniting, open the valves of the oxygen cylinder and acetylene cylinder respectively according to the operating procedures.,cause the low pressure oxygen gauge to indicate at0.2~0.5MPaabout,The pressure gauge of acetylene gas indicates at0.05MPaabout。Then slightly open the oxygen valve of the welding torch。Then slightly open the acetylene gas valve on the welding torch,at the same time,Rapid ignition from the back of the tip。Never fire on the front of the tip,so as not to burn hands。Adjustable after ignition,The adjustment of the two valves is to adjust the ratio of oxygen and acetylene gas entering the mixed gas of the welding torch,to get different flames。

specific welding: when welding,Follow the steps strictly,otherwise,Will affect the quality of welding。Clean or flare the surface of the fittings to be welded,The expanded bell mouth should be smooth、Righteousness,No burrs and cracks,uniform thickness,Sand the part of the copper pipe joint to be welded clean with sandpaper,Finally wipe with a dry cloth。Otherwise it will affect the solder flow and soldering quality。


1 2 tube od brass flared tube inverted male elbow

1 2 tube od brass flared tube inverted male elbow


Insert the copper pipes to be welded overlapping each other,and center-aligned。when welding,Welded parts must be preheated。Weld the flame-baked copper pipe,When the copper tube is heated to purple,Welding with silver electrodes。Put the solder against the solder joint after removing the flame,Let the solder melt and flow into the soldered copper parts,The temperature after heating can reflect the temperature through the color。

(1 2 tube od brass flared tube inverted male elbow)Best for fast welding with a strong flame,Minimize welding time,to prevent the formation of excessive oxides in the pipeline。Oxides will cause fouling along the flow surface of the refrigerant,even seriously damage the compressor。

1 2 tube od brass flared tube inverted male elbow


when welding,When the solder is not fully solidified,Never shake or vibrate the copper pipe,Otherwise, cracks will occur in the welded part and lead to leakage。Allow the weldment to cool naturally after welding,Do not use water or cryogenic substances to rapidly cool weldments。

Refrigeration system charged with refrigerant,Do not solder without draining,It is not possible to carry out welding repairs when the refrigeration system is still leaking,To prevent the refrigerant from encountering an open flame to produce toxic phosgene,poison the human body,even explode!

Four、Welding quality inspection

(1 2 tube od brass flared tube inverted male elbow)Check whether the sealing of the weld is good。After adding refrigerant or nitrogen to stabilize for a certain period of time,Absolute leak-free welds have been tested with soapy water or other methods,after welding,Necessary inspections should be carried out。

When the air conditioner is running,No cracks in the weld due to vibration(sew)Phenomenon。The pipeline should not be blocked due to debris entering during welding,Also can not enter moisture due to improper operation。When refrigeration and air conditioning work,Welded surface should be clean、No oil pollution。


1 2 tube od brass flared tube inverted male elbow


In summary,During copper pipe welding,If the operation is improper, it is easy to cause false welding、Erosion and Dissolution、burn with

Defects such as burn-through,therefore,Strengthen process control during use,Master the process requirements。