Red copper pipe is a common type of non-ferrous metal pipe in our lives, and it is also called copper pipe. Copper pipe has the characteristics of light weight, good thermal conductivity, and high low temperature strength, so it is often used in welding. So what are the welding methods for copper pipes? Follow the editor to find out.

Common welding methods for red copper pipes include manual arc welding, gas welding and manual argon arc welding, and automatic welding can also be used for large structures.

1. Manual arc welding

1. Before manual arc welding, the edge of the weld should be cleaned, and the thickness of the weldment should be greater than 4 mm, and the preheating must be done before welding. The preheating temperature is generally about 400-500℃.

2. A short arc should be used when welding, and the welding rod should not swing laterally. When the welding rod makes a reciprocating linear motion, it can improve the shape of the weld.

3. Welding should be carried out in a well-ventilated place to prevent copper poisoning. And after welding, use a flat-head hammer to strike the weld to eliminate stress and improve the quality of the weld.

2. Gas welding

Butt joints are the most commonly used for welding copper pipes, and lap joints and T-joints are used as little as possible. In the gas welding, two kinds of welding wires can be used, one is the welding wire containing deoxidizing elements; the other is the general red copper wire and the cut strip of the base metal, and the neutral flame should be used for the gas welding of the red copper pipe.

Three, manual argon arc welding

1. Before manual argon arc welding of red copper pipes, the oxide film, oil and other dirt on the welding edge of the workpiece and the surface of the welding wire should be cleaned to avoid defects such as pores and slag inclusion. There are two cleaning methods: mechanical cleaning and chemical cleaning.

2. According to the plate thickness and groove size, the assembly gap of the butt joint of the copper pipe should be selected within the range of 0.5-1.5 mm.

3. This kind of welding method usually adopts DC positive connection, 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, it is necessary to increase the welding speed, reduce the argon consumption and preheat the weldment. When the plate thickness is less than 3 mm, the preheating temperature is 150-300°C; when the plate thickness is greater than 3 mm, the preheating temperature is 350-500°C. It should be noted that the preheating temperature should not be too high, otherwise the mechanical properties of the welded joint will be reduced.