Repair welding of heat exchanger

There may be many reasons for the leakage of the heat exchanger tube sheet. It may be poor welding quality, or it may be defects in the tube sheet itself causing leakage points. When a welder performs repair welding, if the operation is improper or the welding technique is not up to standard, it may aggravate the original leakage problem or create new leakage points. The reasons for the increase in leakage points after welders repair welds may include the following points:: 1. Poor welding quality during repair welding: When welders perform repair welding, unreasonable selection of welding process parameters, improper weld design, mismatched welding materials and other factors may cause poor welding quality, resulting in new leaks. 2. Stress concentration caused by repair welding: During the repair welding process, the temperature change caused by the welding heat will cause stress concentration on the tube sheet. If the stress concentration near the weld is large, the original tube sheet defects may expand, resulting in new leaks. 3. Improper selection of repair welding materials: If the welding materials used during repair welding are incompatible with the original materials, especially if there are differences in corrosion resistance and mechanical properties, it may cause corrosion or cracks between the repair welding part and the original tube sheet, thereby causing new leaks. In this case, it is recommended to re-evaluate the condition of the tube sheet before repair welding to determine whether the tube sheet is suitable for repair welding. At the same time, to find the root cause of the increase in leakage points caused by repair welding, it may be necessary to re-select a suitable welder or optimize the welding process. If the leakage is severe, you may need to consider replacing the tube sheet with a new one to solve the problem. It is best to ask professional technicians to conduct on-site inspection and analysis in order to give more accurate suggestions and solutions. .

First of all, we need to check whether it is a leak in the repair welding or a new leak. If it is a leak in the repair welding, it is a repair welding problem. If it is a new addition, it depends on whether the pipes are unevenly distributed around the repair welding area. ； If it is around the original leaking pipe, it is necessary to consider whether there is a structural problem with the heat exchanger or whether the original leaking pipe has washed away the surrounding pipes. If the design structure problem is difficult to solve, if it is washed out, the surrounding areas that are not leaking when the pipe is blocked must also be blocked. If the newly added leaky pipes are unevenly distributed, it is a material selection or manufacturing problem that cannot be solved.

What are the materials of heat exchange tubes and tube plates?

This post was last edited by wanlirn on 2023-9-6 11:30. It’s normal for more leaks to occur. Please patch it. Our company has not accepted it for nearly 20 years. How much does it cost to repair heat exchanger tubes? How much does it cost to make a sticky package?

Did it leak after the patch was applied and then pressed? Generally speaking, even if the repaired area is not good, it will not be extended to other places.

Caused by the entrance and exit effect. Doesn’t T2T have an expanded tube?

This post was last edited by Zibo Wanhua on 2023-9-8 09:24. Continue to follow

The occurrence of leaks means there is a problem. Solving the leaks does not mean solving the problem, and then new leaks will occur.

First find out the cause of the leakage, whether it is the wrong material, or the tube is too long, and the thermal expansion coefficient is not taken into account. Simply plugging the pipe is not the right choice. Generally, tube-sheet weld joint leakage is caused by two reasons. 1. The current is too high during welding, which destroys the prestress of the original plate. 2. There is no expansion joint on the shell side, and the tubes frequently alternate between hot and cold. The thermal expansion coefficient causes the welding joint to break.

It seems that the welding energy is too high, resulting in excessive welding deformation and affecting the adjacent pipe heads. It may also be that the pipe head itself is almost corroded, and the welding stress causes it to desolder.