At present, the welding methods of stainless steel industrial welded pipes mainly include argon arc welding, high frequency welding, plasma welding and laser welding. Different welding methods have different characteristics. Among them, argon arc welding and high frequency welding are used relatively frequently. Below, we will give you a detailed introduction to the three commonly used welding technology.

Argon arc welding

Stainless steel welded pipe requires deep penetration, no oxide inclusions, and the heat affected zone is as small as possible. Tungsten inert gas shielded argon arc welding has good adaptability, high welding quality and good penetration performance. Its products are used in the chemical industry. , Nuclear industry and food industry are widely used.

The low welding speed is the shortcoming of argon arc welding. In order to increase the welding speed, argon arc welding with a three-electrode torch is generally used. The welded steel pipe wall thickness S≥2mm, and the welding speed is 3-4 times higher than that of a single torch. The quality has also been improved. The combination of argon arc welding and plasma welding can weld steel pipes with larger wall thickness. In addition, 5-10% hydrogen in argon gas, and high-frequency pulse welding power supply can also increase the welding speed.

High frequency welding

Frequency welding has higher power supply power, and can achieve higher welding speed for steel pipes of different materials and outer diameter and wall thickness. Compared with argon arc welding, it is more than 10 times the maximum welding speed. Therefore, the production of general-purpose stainless steel pipes has a higher productivity.

Because the high frequency welding speed is high, it is difficult to remove the burrs in the welded pipe. At present, high-frequency welding stainless steel pipes are not yet accepted by the chemical and nuclear industries, which is one of the reasons. In terms of welding material, high-frequency welding can weld various types of austenitic stainless steel pipes. At the same time, the development of new steel grades and the advancement of forming welding methods have also successfully welded ferritic stainless steel AISI409 and other steel grades.

Combination welding technology

Combination welding methods include: argon arc welding and plasma welding, high frequency welding and plasma welding, high frequency preheating and three torch argon arc welding, high frequency preheating and plasma plus argon arc welding. Combination welding increases the welding speed very significantly. The weld quality of the combined welded steel pipe using high frequency preheating is equivalent to that of conventional argon arc welding and plasma welding. The welding operation is simple, and the entire welding system is easy to realize automation. This combination is easy to connect with existing high frequency welding equipment and investment Low cost and good benefit.

Various welding methods of stainless steel welded pipe have their own advantages and disadvantages. How to maximize the strengths and avoid weaknesses and combine several welding methods to form a new welding process to meet people’s requirements for the quality and production efficiency of stainless steel welded pipe is a new trend in the current development of stainless steel welded pipe technology.