Welding technology of thick copper plate to thick copper plate

1. What kind of welding machine is suitable?

2. If you use the most simple water welding, can it be achieved?

3. How to do it specifically:

There are various welding methods of copper, and different welding methods of copper products are also different.Generally used methods are gas welding, manual carbon arc welding, manual arc welding and manual argon arc welding and other four methods, large structures can also be used automatic welding.

(1) Gas welding

(A) Gas welding of copper

Welding copper (commonly known as industrial pure copper) is most commonly used butt joint.Welding wire can be used for gas welding, one is a wire containing deoxy elements, such as wire 201, 202;The other is a general copper wire and base metal cutting, using gas agent 301 as a flux.

(B) Gas welding of brass

Because of the low temperature of the gas welding flame, the evaporation of zinc in brass is less than that of electric welding, so in brass welding, gas welding is the most commonly used method.The welding wires used for brass gas welding are: wire 221, wire 222 and wire 224, etc. These welding wires contain silicon, tin, iron and other elements, which can prevent and reduce the evaporation and burning loss of zinc in the molten pool, which is conducive to ensuring the performance of the weld and preventing the generation of pores.The fluxes commonly used in gas welding brass are solid powder and gas flux. The gas flux is composed of methyl borate and methanol.Flux such as gas agent 301.

(2) carbon arc welding

(A) carbon arc welding of red copper, the electrodes used for carbon arc welding are carbon electrode and graphite electrode.The welding wire used for copper carbon arc welding is the same as that used for gas welding. It can also be used for base metal shear bar and for gas welding of copper flux, such as gas agent 301, etc.

(B) brass carbon arc welding, brass carbon arc welding, according to the composition of the base metal, wire 221, wire 222, wire 224 and other welding wire, can also be used for self-made brass welding wire.Welding can use gas agent 301 as flux.Welding shall be performed with a short arc to reduce evaporation and burn loss of zinc. 

(3) manual arc welding

(A) manual arc welding of copper

Copper electrode copper 107, the core for copper (T2, T3).The power supply should adopt DC reverse connection.When welding, short arc should be used, and the electrode should not swing laterally.Reciprocating linear motion of the electrode can improve the shape of the weld.The long weld shall adopt the step back welding method.The welding speed should be as fast as possible.In multi-layer welding, slag between layers must be thoroughly removed.

Welding should be carried out in a well-ventilated place to prevent copper poisoning.After welding, flat hammer should be used to strike weld seam to eliminate stress and improve weld quality.When the thickness of the weldment is greater than 4 mm, it must be preheated before welding, and the preheating temperature is generally about 400~500℃. 

(B) Manual arc welding of brass

In addition to copper 227 and copper 237, self-made electrode can also be used for welding brass.Direct current power supply is used to connect the electrode to the negative electrode.The surface of weldment should be cleaned carefully before welding.Grooved Angle should not be less than 60~70 ° in general. In order to improve the weld forming, welding parts should be preheated 150~250 ° C.The operation should be short arc welding, not transverse and back and forth swing, only for linear movement, welding speed should be high.Brass welds in contact with corrosive media such as sea water and ammonia must be annealed after welding to eliminate welding stress.

(4) manual argon arc welding

(A) Manual argon arc welding of copper

The used wire is wire 201(special copper wire) and wire 202, but also the use of copper wire, such as T2.

Usually, direct current connection is used, that is, tungsten electrode is connected to the negative electrode.In order to eliminate the porosity and ensure the reliable fusion and penetration of the weld root, it is necessary to increase the welding speed, reduce the consumption of argon gas, and preheat the welds.When the thickness of the plate is less than 3 mm, the preheating temperature is 150~300℃.When the thickness of the plate is greater than 3 mm, the preheating temperature is 350~500℃.The preheating temperature should not be too high, otherwise the mechanical properties of the welded joint will be reduced.Before welding, the oxide film, oil and other dirt on the welding edge of the workpiece and the surface of the welding wire must be cleaned up to avoid pores, slag inclusion and other defects.Cleaning methods are mechanical cleaning and chemical cleaning.When the thickness of butt joint plate is less than 3mm, no groove is opened;When the thickness of the plate is 3 ~ 10mm, V-shaped groove is opened, and the groove Angle is 60 ~70 °.When the plate thickness is greater than 10mm, open X groove, groove Angle is 60 ° ~70 °;In order to avoid penetration, generally do not leave blunt edge.According to the thickness of the plate and the size of the groove, the assembly clearance of the butt joint is selected within the range of 0.5 ~ 1.5mm.Manual argon arc welding of copper, is usually the use of direct current connection, that is, tungsten electrode is connected to the negative electrode.In order to eliminate the porosity and ensure the reliable fusion and penetration of the weld root, it is necessary to increase the welding speed, reduce the consumption of argon gas, and preheat the welds.

(B) Manual argon arc welding of brass

Standard brass wire: wire 221, wire 222 and wire 224, can also use the same composition as the base material as the filling material.Welding can be either direct current or alternating current.When AC welding is used, the evaporation of zinc is lighter than when direct current welding is used.Usually do not preheat before welding, only when the thickness of the plate is relatively large.Welding speed should be as fast as possible.The welding parts should be heated at 300~400℃ for annealing treatment after welding to eliminate welding stress to prevent cracks in the welding parts during use.