Discuss the reasons for leakage at the weld between the lower head and the nozzle-----------------
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This post was last edited by kareale88 on 2018-10-19 at 11:06. Let’s discuss the reasons for leaks at the welds between the end caps and the pipes after one year of use----------------- Diameter: 400; material: 304 stainless steel; wall thickness of both the pipes and the shell: 3 mm. I hope everyone can share their thoughts on all possible causes of these leaks. 1. Inadequate welding. 2. Excessive grinding. 3. Excess chlorine ions in the water. 4. Problems with the material itself. 5. Use under excessive pressure. After ruling out these possibilities, there may be other causes; I hope everyone can share their opinions. Pictures cannot be uploaded here, so they have been sent to the second floor below
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The wall thickness is 3 mm – I’m not sure whether this refers to the actual measured value or the nominal thickness of the plate. What are the pressure and temperature inside the equipment? Although the diameter isn’t large, the wall thickness really can’t be considered thick. With such a thin thickness, it’s not easy to ensure welding quality.
Other reasons: 1. Load at the pipe connection point; 2. Whether the liquid level height is taken into account; 3. Whether there is vibration in the pipeline at the connection point (causing fatigue)
Since there is a leak, it means there are penetrating cracks. It is actually the cause of the cracks. Argon arc welding is unlikely to cause cracks; has the original poster ruled out stress corrosion cracking due to CL ions? Even if the chloride content in the water has been measured, the possibility of chloride accumulation at the cracks cannot be ruled out. Furthermore, since it is a lower pipe, will there be alternating loads?
3. It is very likely that the chloride ion level in the water is too high.