welding methods of red copper
1. Common welding methods
The methods of welding red copper include gas welding, manual carbon arc welding, manual arc welding and manual argon arc welding. Automatic welding can also be used for large structures.
(1) Gas welding of red copper
The most commonly used copper is butt joints, and lap joints and T-joints are used as little as possible. Two kinds of welding wires can be used for gas welding, one is the welding wire containing deoxidizing elements, such as wires 201 and 202; the other is the cut strip of common red copper wire and base metal, using gas agent 301 as the flux, and should be used for gas welding of red copper Neutral flame.
(2) Manual arc welding of red copper.
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℃. Welding with copper 107 electrode, the power supply should adopt DC reverse connection. When welding, a short arc should be used, and the electrode should not be oscillated laterally. The reciprocating linear motion of the electrode can improve the formation of the weld seam. The long weld seam should adopt the gradual back welding method, and the welding speed should be as fast as possible.
When multi-layer welding, the slag between the layers must be completely removed. Welding should be carried out in a well-ventilated place to prevent copper poisoning. After welding, use a flat-head hammer to strike the weld to eliminate stress and improve the quality of the weld.
(3) Manual argon arc welding of red copper
In the manual argon arc welding of red copper, the welding wire used includes wire 201 (special red copper welding wire) and wire 202, and red copper wire, such as T2, is also used.
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 defects such as porosity and slag inclusion. There are mechanical cleaning methods and chemical cleaning methods. When the thickness of the butt joint is less than 3mm, the groove shall not be opened;
When the plate thickness is 3～10mm, open the V-shaped groove, and the groove angle is 60°～70°; when the plate thickness is greater than 10mm, open the X-shaped groove, and the groove angle is 60°～70°; to avoid unwelded Transparent, generally do not leave blunt edges. According to the plate thickness and groove size, the assembly gap of the butt joint is selected in the range of 0.5 to 1.5 mm.
For manual argon arc welding of red copper, DC positive connection is usually adopted, that is, the tungsten electrode is connected to the negative electrode. In order to eliminate pores and ensure reliable fusion and penetration at the root of the weld, the welding speed must be increased, the argon consumption must be reduced, and the weldment must be preheated. When the plate thickness is less than 3mm, the preheating temperature is 150～300℃; when the plate thickness is greater than 3mm, 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.
(4) Carbon arc welding of red copper
The electrodes used in carbon arc welding are carbon electrodes and graphite electrodes. The welding wire used for carbon arc welding of red copper is the same as that of gas welding, and the base material can also be cut, and the flux for gas welding of red copper can be used, such as gas 301.
