Leakage issue in the air heater tubes
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Compressed air, pressure 0.25 MPa, temperature around 50 degrees; superheated steam, pressure 0.2 MPa, temperature around 260 degrees; material: 304； Leakages frequently occur at the weld joints of the tubes in the heater tube sheet; there are minor leaks around these welds inside the tubes. Moreover, ductile cracks tend to form during repair welding, making it impossible to seal the leaks. I’m not sure where the problem lies; I would be very grateful for any advice you can provide
It would be better if the manufacturer got involved to analyze and handle it. Hehe, they all say it’s 304, but who the hell knows for sure.
It seems the main issue is doubt regarding the material; it should be tested to determine its quality, right? After all, the welding process itself cannot be verified
How long has the heater been in use? Is the heat exchange tube properly expanded? In addition to the material being tested, factors such as whether fatigue will occur and whether the steam contains Cl need to be considered.
It has only been in use for two to three months, and the heat exchange tubes have not been expanded. The question is: is it required to expand the tubes when manufacturing a 304 stainless steel tube heat exchanger? There are no specific requirements regarding this in the GB standards
Could the cracking of the air cooler be caused by phase change: L
The temperature difference for heat exchange is too large; consider the material issue
Material? Let’s use carbon steel instead; it rusts easily. 304 won’t work, so what would be a good choice? It’s not a corrosion issue; it’s a phase transition issue. How to choose the material?
Excessive temperature difference leads to weld cracking caused by thermal stress.