The influence of production process factors of SSAW steel pipe on the quality of single side welding and double side forming weld mainly includes welding current, welding speed, number of welding layers, type of electrode and diameter of electrode.
 
1. Welding current. Correct selection of welding current directly affects the final welding quality. Excessive welding current can increase productivity and penetration depth, but it is prone to defects such as occlusion and welding, and increase the trend of porosity. Especially when the vertical welding operation is difficult to control the molten pool, the occurrence of welding defects, the increase of arc length, the too small welding current and the decrease of penetration depth are prone to defects such as incomplete penetration, poor fusion, slag inclusions and disconnection. During the training period, it is a difficult problem for those students who have just come into contact with welding. In the process of one-sided welding of plate and plate, the primary welding current is very large, which leads to many different sizes of welding on the back of our plate. The bottom welding is too small, resulting in unmelted defects in welding. This defect directly leads to a significant reduction in welding quality, which is one of the important defects in industrial production.


2. Welding speed. Welding speed is the main parameter to express the production efficiency of welding. Reasonable selection of welding express delivery is particularly important to ensure welding quality. The welding speed is too fast, so the temperature of the molten pool is not enough, which may lead to defects such as incomplete penetration, incomplete fusion, poor welding formation and so on. Welding speed is too slow, high temperature for a long time, the width of heat affected zone increases, the grain size of welded joint becomes coarser, mechanical properties decrease, welding deformation increases, at the same time, the welding speed is too low, the thickness of each layer increases, resulting in slag reflux, slag inclusion and other defects. Cover welding speed.


3. improper selection of welding layer. The quantity of weld layer formed by one-sided welding and two-sided welding also has certain influence on the quality of weld. The plasticity of weld metal is harmful if the thickness of each layer is too large. During the welding process, the welding slag is easy to flow backward, leading to defects such as slag rather than fusion, but the thickness of each layer should not be too small, so as to avoid bad fusion on both sides of the weld.


4. The shape and diameter of the electrode. The properties of welded metals are mainly determined by the melting of electrodes and welded metals. Therefore, the selection of wire type is an important factor affecting the welding quality. In addition to the effect of electrode diameter on acoustic field rate, it also has a certain effect on welding quality. The diameter of the electrode is too large and the underlying layer is underground. The weld pool is difficult to control and is prone to welding defects. What kind of base metal, choose the welding material with the same quality as base metal. The choice of welding diameter is too big. It is very difficult for us to weld a good weld on the back of the test board.