Red Copper Welding Technology

Red copper welding technology

welding red copper (commonly known as industrial pure copper) methods include gas welding, manual carbon arc welding, manual arc welding and manual argon arc welding and other methods. Automatic welding can also be used for large structures.

1. gas welding of copper

Butt joints are most commonly used for welding copper. Lap joints and T-joints are seldom used. Gas welding can use two kinds of wire, one is containing deoxidized elements, such as wire 201, 202; the other is a general copper wire and base metal cutting strip, using gas flux 301 as flux. Neutral flame should be used for gas welding of copper.

2. manual arc welding of copper

In manual arc welding, the copper electrode is 107, and the welding core is copper (T2, T3). The edge of the weld should be cleaned before welding. When the thickness is more than 4 mm, it must be preheated before welding, and the preheating temperature is generally about 400~500 C. When welding with copper 107 electrode, DC reverse connection shall be adopted.

Short arc should be used when welding, and the electrode should not be swinging horizontally. The linear movement of the welding rod can improve the forming of the weld. The long weld seam should adopt the method of step back welding. When multilayer welding, the slag between layers must be completely removed.

Welding should be carried out in a well ventilated place to prevent copper poisoning. After welding, use flat head hammer to strike weld seam, eliminate stress and improve weld quality.

3. Manual argon arc welding of copper

In manual argon arc welding of copper, the welding wires used are wire 201 (special copper wire) and wire 202, and copper wire, such as T2.

Before welding, the welding edge of the workpiece and the oxide film and oil on the surface of the welding wire must be cleaned up to avoid such defects as porosity and slag inclusion. The cleaning methods include mechanical cleaning and chemical cleaning.

When the thickness of butt joint is less than 3 mm, no groove is opened; when the thickness of plate is 3-10 mm, V-groove is opened, the angle of groove is 60-70 degrees; when the thickness is more than 10 mm, X-groove is opened, the angle of groove is 60-70 degrees. In order to avoid incomplete penetration, no blunt edges are usually left. According to plate thickness and groove size, the gap of butt joint is selected from 0.5 to 1.5 mm.

The manual argon arc welding of copper is usually made by direct current connection, that is, tungsten electrode is connected to the negative electrode. In order to eliminate porosity and ensure reliable fusion and penetration at the root of weld, it is necessary to increase welding speed, reduce argon consumption and preheat the weldment. When the thickness of the plate is less than 3 mm, the preheating temperature is 150 ~ 300 C; when the thickness is more than 3 mm, the preheating temperature is 350 ~ 500 C. The preheating temperature should not be too high, otherwise the mechanical properties of the welded joint will be reduced.

4. Carbon arc welding of copper.

Carbon arc welding electrodes have carbon electrodes and graphite electrodes. Welding wire for purple copper carbon arc welding is same as gas welding. It can also use base metal cutting, and flux, such as gas agent 301.