Three welding techniques for stainless steel welded pipes

At present, the welding methods of stainless steel welded pipes used in the industry mainly include argon arc welding, high-frequency welding, plasma welding, and laser welding. Several welding methods have their characteristics. At present, the most used are argon arc welding and high-frequency welding.

1. Stainless steel welded pipe technology - argon arc welding

Stainless steel welded pipes require deep penetration, no oxide inclusions, and as small a heat-affected zone as possible. Tungsten inert gas shielded argon arc welding has good adaptability, high welding quality, and good penetration performance. Its products are widely used in the chemical industry. , nuclear industry and food industries are widely used. The disadvantage of argon arc welding is that the welding speed is not high. To improve the welding speed, argon arc welding with a three-electrode torch is generally used. Quality has also 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 then a high-frequency pulse welding power source can also increase the welding speed.

2. Stainless steel welded pipe technology - high-frequency welding

High-frequency welding has a higher power supply and can achieve a higher welding speed for steel pipes of different materials and outer diameters and wall thicknesses. Compared with argon arc welding, its welding speed is more than 10 times. Therefore, the production of general-purpose stainless steel pipes has high productivity. Because of the high speed of high-frequency welding, it is difficult to remove the burrs in the welded pipe. At present, high-frequency welded stainless steel pipes cannot be accepted by the chemical and nuclear industries, which is also the reason. From the perspective of welding materials, 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 steel grades such as ferritic stainless steel AISI409.

3. Stainless steel welded pipe process technology - combined welding technology

Combination welding methods include argon arc welding plus plasma welding, high-frequency welding plus plasma welding, high frequency preheating plus three-torch argon arc welding, and high frequency preheating plus plasma plus argon arc welding. Combination welding increases the welding speed very significantly. For the combination welded steel pipe using high frequency preheating, the weld quality is comparable 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 the existing high-frequency welding equipment. Low cost and benefit. Various welding methods of stainless steel welded pipes have their advantages and disadvantages. How to make use of strengths and avoid weaknesses, combine several welding methods to form a new welding process, and meet people's requirements for stainless steel welded pipe quality and production efficiency, is a new trend in the current development of stainless steel welded pipe technology.