Can the plates of a plate heat exchanger made of 304L steel be welded?
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I have a plate heat exchanger whose 304L plates have several small holes in them; they’re about the size of large needle pricks. What methods can be used to repair them? Can TIG welding be used? This post was last edited by Lan Meng on 2009-2-5 15:03.]
Heat exchange plates are generally formed by single-strike stamping. This welding will affect the heat exchange performance. This situation usually indicates pitting corrosion. It is recommended to replace the plate.
If the welding process is up to standard, welding can be carried out. But it is necessary to ensure that improper repair methods do not cause further damage to the equipment.
If your TIG welding skills are up to par, you can use welding to repair the leaks. If that doesn’t work, the plate will need to be replaced.
Welding is not recommended; the presence of pitting indicates that there may be some more subtle perforations in the plate. There are no convenient inspection methods on site either. (Fluorescence detection is generally required.) It is recommended to replace the plate.
Be careful not to cause welding through; it’s best to take it back to the manufacturer for repair
Corrosion in plate heat exchangers is usually pitting or stress corrosion, manifesting as large pinholes or tiny cracks. If there are only a few such defects, they can be welded using TIG welding; however, if there are many, welding is not an option – the plates simply need to be replaced. It should be added that the formation of pitting is related to the heat exchange medium, the material of the plates, and the operating conditions of the equipment. Once pitting occurs on a large scale, welding becomes impossible. The cause of stress corrosion is mainly related to the stresses generated during the pressing process of the plate; the resulting micro-cracks are only localized, and such plates can still be welded. This post was last edited by wfw960209 on 2009-2-6 07:56.]
The best approach is to take it back to the manufacturer for repair or to have a new plate installed. If attempting repairs oneself, the equipment and techniques available in most factories are not sufficient; moreover, the material of the welding rods must be identical to that of the heat exchange plates.
If it’s not repaired, leaks will occur. Temporary patches can be used to stop the leaks for now. There are several cracks already, and over time more cracks will appear; this heat exchanger won’t last long.
Check whether your plate heat exchanger is pressure-rated; if it isn’t, it can be welded. Additionally, you are now noticing several dew points, which may be caused by corrosion. What you see now is only the surface phenomenon; there might be more issues internally that just can’t be detected at the moment. It is recommended to replace it……
Sure, our company uses TIG welding for this purpose. It is required that the welders have skilled techniques; it’s better not to use industrial welding machines – those small welding machines used for welding stair handrails would work fine. The panels can be used for another half year before they need to be replaced. Last edited by eddy-8280103 on 2009-2-10 15:46