Welding of 12Cr2Mo1R nozzles
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The welding is preheated to 150°C as required by the process; skilled welders are available. Welding of straight pipes poses no problem, but when welding pipes at an angle, one crack appears after each weld, and the reason for this cannot be determined.
The post owner’s item probably cracked before welding was completed; the groove in the photos isn’t fully welded yet
You can try raising the preheating temperature a bit more
Well, what I mean is whether the temperature between layers is under control; it can’t be just preheated without maintaining that temperature – if it cools down right after welding, then there’s no difference from not preheating at all when welding the next layer
It was kept warm the whole time, and while welding, there was a loud crackling sound
It cracked before welding was completed; after welding, post-heating at 350°C for 3 hours was applied
The nozzles are more or less the same size; it’s fine to weld the one in the center no matter how, but for those inserted at an angle, one is welded and then another cracks
Does the parent material matter? We’ve encountered situations where the material specified in the drawings did not match the actual material used; after all, it’s a repair job, and we don’t know what happened to the original equipment. Manufacture or repair
For manufacturing, the base material has been re-inspected; those from Wugang are fine
The problem isn’t solved yet; don’t let the post sink :(