Different from raw copper, the welding method is not the same.
The methods of welding red copper (namely, the industrial pure copper generally called) include gas welding, manual carbon arc welding, manual electric arc welding and manual argon arc welding, etc., and automatic welding can also be used for large structures.
1.Gas welding of red copper
The butt joint is most commonly used for welding red copper, lap joint and T-joint are rarely used as far as possible.Gas welding can use two kinds of welding wire, one is containing deoxidized elements, such as wire 201, 202;The other is the general red copper wire and base material cutting strip, using gas agent 301 as flux.Neutral flame should be used in gas welding of red copper.
2.Manual arc welding of red copper
Red copper electrode copper 107 is used in manual arc welding, and the core is red copper (T2 and T3).The edge should be cleaned before welding.When the thickness of welding parts is more than 4 mm, it must be preheated before welding. The preheating temperature is generally around 400~500℃.Welding with copper 107 electrode, the power supply should be dc reverse connection.
Short arcs should be used in welding, and the electrode should not swing laterally.The forming of the weld can be improved by the reciprocating linear motion of the electrode.The long weld shall be backweld step by step.The welding speed should be as fast as possible.In multilayer welding, the slag between layers must be thoroughly removed.
Welding should be done in a well-ventilated place to prevent copper poisoning.After welding, the flat head hammer is used to strike the weld to eliminate the stress and improve the weld quality.
3.Manual argon arc welding of copper
In the manual argon arc welding of red copper, the welding wire used is wire 201(special red copper welding wire) and wire 202, also use red copper wire, such as T2.
Before welding should be the workpiece welding edge and welding wire surface oxidation film, oil and other dirty things must be cleaned, to avoid pores, slag and other defects.Cleaning methods include mechanical cleaning method and chemical cleaning method.
When the thickness of butt joint plate is less than 3mm, no groove shall be opened;When the thickness of the plate is 3 ~ 10 mm, the v-shaped groove is opened and the groove Angle is 60~70.When the thickness of the plate is more than 10 mm, the x-shaped groove is opened and the groove Angle is 60~70.In order to avoid incomplete welding, generally do not leave a blunt edge.According to the plate thickness and groove size, the assembly clearance of butt joint is selected within the range of 0.5 ~ 1.5 mm.
Manual argon arc welding of red copper usually uses dc positive connection, namely tungsten electrode is connected with negative electrode.In order to eliminate pores and ensure reliable fusion and penetration of weld root, welding speed must be increased, argon gas consumption reduced, and welding parts preheated.When the plate thickness is less than 3 mm, the preheating temperature is 150~300℃.When the plate thickness is more than 3 mm, the preheating temperature is 350~500℃.Preheating temperature should not be too high, otherwise the mechanical properties of welded joints will be reduced.
There is also carbon arc welding of red copper. Carbon arc welding uses carbon electrode and graphite electrode.The welding wire used in red copper carbon arc welding is the same as that in gas welding. The base material can also be cut and the flux of red copper can be used in gas welding, such as gas agent 301, etc.