Timing of non-destructive testing for high-strength steel and chromium-molybdenum steel after welding and immediate heat treatment

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This post was last edited by Zhan Yao Chu Mo on 2019-1-28 at 10:21. Recently, there have been several devices that are not large in size and are made of high-strength steel or chromium-molybdenum steel; the drawings specify that non-destructive testing should be carried out at least 24 hours after welding is completed. Now, engineers at the manufacturing plant propose continuous operation with tightly linked processes: as soon as welding is completed, the parts are transferred to the heat treatment furnace, allowing hydrogen to dissipate and thus preventing the formation of delayed cracks. The manufacturing requirement specifies that non-destructive testing shall be carried out 24 hours after welding is completed on the drawings. Because they calculated that welding and heat treatment can be completed during the day, and then at night the testing facility can use film to conduct radiographic testing. If it’s 24 hours later, it will be during the day the following day, and non-destructive testing cannot be carried out during the day; it has to wait until night, which results in a full day’s delay. It is not conducive to manufacturers meeting tight deadlines. The manufacturer is confident about the quality; heat treatment was carried out immediately after welding, which allowed hydrogen to dissipate and prevented the formation of delayed cracks, so there is no need to wait another 24 hours. What do everyone think about this issue?