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Copper Tube Information

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annealing brass you tube

author:MF manufacturerstime:2022-03-11 02:22:36

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1、 General

Refrigeration system in refrigeration and air conditioning,Non-ferrous metal materials such as copper and aluminum are generally used,in manufacturing、During installation and maintenance,Welding of pipes is a key part,It not only affects the beauty,More importantly, it affects whether the system can work normally or not.,must be given great attention。

annealing brass you tube


2、 Solder selection

(annealing brass you tube)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。

(annealing brass you tube)annealing brass you tube(annealing brass you tube)


2.1 Welding of similar materials

(annealing brass you tube)

2.1.1Brazing of copper to copper

Optional phosphor bronze solder or phosphor bronze solder with low silver content,Such as2%or5%silver based solder。This solder is cheaper,and a good solution,caulking and wetting process,No flux required。

annealing brass you tube


(annealing brass you tube)

2.1.2Welding of copper and steel

annealing brass you tube


Optional brass bar solder with appropriate flux。when welding。Heat the solder to a certain temperature and insert it in the flux,After the flux is melted, it adheres to the solder,However, 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。

2.2.2Welding 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。

3、welding operation

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 flame is adjusted according to the oxygen、Acetylene gas volume ratio can be divided into carbonization flame、Neutral flame and oxidizing flame。

(annealing brass you tube)3.1 Types and characteristics of flames

annealing brass you tube


3.1.1carbonization flame

Its 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 about2700about,Can be used for baking pipes, etc.。

3.1.2neutral flame

(annealing brass you tube)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。

3.1.3Oxidizing 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 selected according to the type of metal to be welded and its properties,Care should be taken to choose and use scientifically。

(annealing brass you tube)3.2 flame regulation

annealing brass you tube(annealing brass you tube)


(annealing brass you tube)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 ocular indicator 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,colleague,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 immersed in the mixed gas of the welding torch,to get different flames。

3.3 welding

annealing brass you tube


(annealing brass you tube)Strictly follow the steps when welding,otherwise,Will affect the quality of welding。

3.3.1Preparation and piping

3.3.1.1 Check that the oxygen and acetylene cylinders are full。

3.3.1.2 Check drawing requirements,Guarantee the completeness of all parts,fully functional。

3.3.1.4 Ensure that the light path of the pipeline is horizontal and vertical,Pay attention to the directionality of each valve。

annealing brass you tube


3.3.1.5 Dimensions and pipe diameters according to drawings,Measure the corresponding length with a tape measure,And use the line marker to touch the position a few times。

3.3.1.6 Thicker copper pipes should be fixed after,Remove with a knife,Make sure the cut is level,not deformed。

3.3.1.7 File the cut burrs with a file,and wipe clean with a rag。

3.3.1.8 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,Will affect solder flow and solder quality。

3.3.1.9 Except for copper and copper welding,All fittings should be cleaned with gauze or stainless steel wire brush before welding,Expose shiny metal surfaces。(Internal surface to be cleaned,Metal shavings and grit should be removed)

3.3.1.10 Insert the copper pipes to be welded overlapping each other(Pay attention to size)and center-aligned。

3.3.1.11 The insertion depth and clearance of copper pipe joints and copper pipes are shown in the table。(Insertion depth approximately equal to pipe diameter)

3.3.2Protect

annealing brass you tube


The picture above shows no nitrogen protection

annealing brass you tube


The picture above shows nitrogen gas protection

3.3.2.1 During welding, low-speed nitrogen gas should be passed through the welded pipe.,prevent oxidation。

3.3.2.2 Acetylene gas should pass through a non-oxidizing welding generator,Prevent oxidation of the outer surface of the welded object。

3.3.3welding

(annealing brass you tube)annealing brass you tube


3.3.3.1 when welding,Welded parts must be preheated。Weld the flame-baked copper pipe,When the copper tube is heated to purple,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,dark red:600Celsius;dark red:700Celsius;Orange:1000Celsius。

3.3.3.2 when welding,Gas welding flame shall not directly heat the electrode。

(annealing brass you tube)3.3.3.3 Easy to deform at high temperature,Damaged parts should be protected accordingly。such as angle valve、Evaporator,The condenser, etc. should be wrapped with wet gauze before welding,For solenoid valves、膨胀阀、Expansion valve、四通阀,Liquid mirror,不能拆的同样采取以上措施。

3.3.3.4 Four-way valve,在焊完后将铜管进行退火时,It must be removed to be removed300摄氏度。

3.3.3.5 Do not take the same measures,冷却,Welding。

(annealing brass you tube)3.3.4补焊

annealing brass you tube


(annealing brass you tube)3.3.4.1 The annealing temperature is not less than,补焊时要将系统试压的氮气放掉,Degrees Celsius。

3.3.4.2 补焊前腰将表面的氧化层,After the welding is completed。补焊后,cool down,在水中淬火后,Dry nitrogen gas cleaning tube oxide and welding slag,不得有水滴存在。

3.3.4.3 Solder,要用氮气将系统吹净。

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