Discussion on the sequence of subsequent operations after welding the heat exchange tubes to the tube sheet
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This post was last edited by Haishuitianbing on 2018-11-11 at 14:55. Discussion on the sequence of heat treatment, expansion jointing, and penetrant testing after welding the heat exchange tubes to the tube sheet in shell-and-tube heat exchangers – everyone please share their opinions
Due to their different views, everyone talked about the advantages of what they considered to be the correct procedure
1. Heat treatment, 2. Expansion joining, 3. Penetrant testing. Reason: 1. From a mechanical perspective—heat treatment is used to eliminate stresses or improve mechanical properties, while expansion joining is employed due to the significant difference in mechanical properties between the heat exchange tubes and the tube sheet; if heat treatment is carried out after expansion joining, it may lead to leaks. And the testing does not cause any changes in mechanical properties; it is merely a testing method ； In terms of the 2 processes, it is heat treatment – expansion fitting – leak testing – re-expansion fitting (in case of leakage) – re-leak testing. . . Expansion welding – heat treatment – leak testing – re-expansion welding (in case of leakage) – reheat treatment – re-leak testing is more reasonable. Testing is always the last step. 3. Heat treatment may also cause leaks, rather than being the cause of expansion joint issues; repeated rework might result from heat treatment. .