Three welding techniques for stainless steel welded pipes

• Stainless steel welded pipe technology--Argon arc welding

Stainless steel welded pipe requires deep weld penetration, does not contain oxide inclusions, the heat affected zone is as small as possible, tungsten inert gas shielded argon arc welding has a better adaptability, high weld quality, weld penetration performance is good, and its products in the chemical industry, the nuclear industry, and food and other industries are widely used.
Welding speed is not high is the shortcomings of argon arc welding, in order to improve the welding speed, generally using three electrode torch argon arc welding, welding steel pipe wall thickness S ≥ 2mm, welding speed than a single torch to improve 3-4 times, welding quality can also be improved. Argon arc welding and plasma welding can be combined to weld a larger wall thickness of the steel pipe, in addition, in the argon gas 5-10% of hydrogen, and then use high-frequency pulsed welding power supply, can also improve the welding speed.

• Stainless steel welded pipe process technology - high frequency welding

Frequency welding has a higher power source power, for different materials, OD wall thickness of the steel pipe can achieve a high welding speed. Compared with argon arc welding, is more than 10 times its maximum welding speed. Therefore, the production of general-purpose stainless steel pipe has a high productivity.
Because of the high frequency welding speed, the removal of burrs in the welded pipe brings difficulties. At present, high-frequency welded stainless steel pipe is not yet acceptable for the chemical and nuclear industries, which is one of the reasons. From the welding material, high-frequency welding can weld various types of austenitic stainless steel pipe. At the same time, the development of new steel grades and advances in molding and welding methods have also successfully welded ferritic stainless steel AISI409 and other steel grades.

• Stainless steel welded pipe technology - combination welding technology

Combination of welding methods are: argon arc welding plus plasma welding, high-frequency welding plus plasma welding, high-frequency preheating plus three torch argon arc welding, high-frequency preheating plus plasma plus argon arc welding. Combined welding to improve welding speed is very significant. For the use of high-frequency preheating of the combination of welded steel pipe weld quality and conventional argon arc welding, plasma welding is comparable to the welding operation is simple, the entire welding system is easy to realize automation, this combination is easy to interface with the existing high-frequency welding equipment, low investment costs, good benefits.