Materials for delayed crack growth in pressure vessels
Thread Content
May I ask, for pressure vessels made of the stress-resistant material 20MnMoⅣ, is non-destructive testing performed 24 hours after welding? Does this material fall into the category of materials prone to delayed cracking? Seek an answer
In my opinion, this material does not exhibit a tendency to develop delayed cracks, and its strength is not high either. I recall that the steel plates used for our equipment frames were of Q370R grade; forgings are also made from this material, and they do not show any tendency to delayed cracking.
Then what is the purpose of non-destructive testing after 24 hours?
If there is no tendency for delayed cracking, there is no need for 24-hour testing； If a tendency for delayed cracking is suspected, testing is required 24 hours after welding; or if there is uncertainty regarding such a tendency, testing 24 hours after welding is done for safety reasons, as this makes it easier to ensure quality.