Relationship between heat treatment and flaw detection
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For pipes that require heat treatment, should flaw detection be carried out first, or heat treatment? Let’s discuss the advantages and disadvantages of each
Heat treatment is carried out first, followed by flaw detection. Flaw detection is used to determine whether the material is of acceptable quality, while heat treatment is a processing step involved in the production of materials that meet the required standards.
This issue has been discussed several times. Heat treatment should be carried out 8 hours after welding in accordance with the specifications; there is clearly no time for flaw detection before heat treatment. Generally, flaw detection is done first, and heat treatment is postponed. There is an advantage to this approach: if testing shows that the product is not up to standard, it can be repaired until it meets the requirements, after which only one heat treatment is needed. On the other hand, if heat treatment is carried out first and testing still reveals that the product is not up to standard, heat treatment will have to be repeated after the repairs are made. However, flaw detection is carried out first followed by heat treatment, and to prevent the occurrence of delayed cracks, ultrasonic flaw detection is performed as well in the end.
If the flaw detection after heat treatment is unsatisfactory, heat treatment must be carried out again after rework
First conduct flaw detection; only after passing the inspection should heat treatment be carried out – this sequence is quite reasonable