First, why do the welding techniques for thin-walled stainless steel pipes require high skill?
Firstly, in terms of construction capabilities, welding is a highly specialized job. Generally, welded pipes cannot be disassembled, making replacement on-site very inconvenient. Because arc welding requires specialized equipment, and the thickness of thin-walled stainless steel pipes is very thin, only highly skilled welders can operate. However, on actual construction sites, the workforce is highly mobile. If personnel without welding operating certificates are allowed to weld, they will not be able to properly adjust the current, argon gas, etc. Furthermore, due to the limited space and human factors on the construction site, incomplete welds, leaks, and even weld-through of the pipes often occur. Although no leakage will occur during pressure testing, this poses a significant construction safety hazard. After a certain period of use, factors such as thermal expansion and contraction can lead to leaks in the stainless steel pipes.
Second, why are there details regarding heat treatment in the welding of thin-walled stainless steel pipes?
The second issue is heat treatment. While thin-walled stainless steel pipes and fittings can be welded to solution-treated areas during factory processing, on-site installation often presents limitations. When austenitic stainless steel slowly passes through temperatures between 450 and 800 degrees Celsius, carbon and chromium carbide precipitates at the grain boundaries, reducing the nearby chromium content and creating chromium-deficient zones, leading to a significant decrease in corrosion resistance. After prolonged use, the most concerning issue is weld corrosion. If the carbon content of the stainless steel is high, it will be evident in the weld, potentially causing failure of the stainless steel pipe. This problem will inevitably occur after a period of use and cannot be controlled through on-site inspection.
Third, what are the impacts of the stainless steel pipe installation environment?
The third point concerns the issue of thermal expansion and contraction. Research on stainless steel materials reveals that the destructive force caused by changes in temperature in the environment is significant. Therefore, thermal expansion and contraction are crucial for the management of stainless steel materials. The thermal expansion effect cannot be simply determined by the tensile force values during product manufacturing. For example, threaded connections used in many applications are easily affected by thermal expansion and contraction. Because stainless steel pipes and fittings cannot be stretched or shortened, fatigue cracks often occur, and the greater the temperature difference, the greater the destructive force.
Therefore, for the connection of thin-walled stainless steel pipes and fittings, if concealed installation is desired, the thermal expansion and contraction properties of the building materials must be fully considered. However, comparative studies show that socket-type fittings welded by argon arc welding are difficult to achieve consistency between the parent pipe/fitting and the weld, and cannot effectively eliminate different stresses. Especially in northern China, where pipeline installation mostly takes place in summer and autumn, the maximum negative temperature difference between the water pipe system and the installation temperature can reach approximately 35 degrees Celsius. Particularly when the temperature drops rapidly, without the installation of pipe expansion joints, axial tension on the pipe can cause tensile cracking of the pipe and fitting welds. If the information processing capability is poor, defects such as porosity and incomplete welds caused by thermal expansion and contraction will gradually become apparent over time.
The above is the content of the welding and forming technology of thin-walled stainless steel pipes. When welding thin-walled steel pipes, three factors need to be considered: the welding personnel’s skills, the heat treatment during welding, and the influence of the stainless steel pipe installation environment. In this way, the thin-walled stainless steel pipes will not deform during the welding process.
Post time: Jan-13-2026