For the container modification shown in the diagram, is post-weld heat treatment required? Is the standard applicable?
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It is a container with a diameter of 2000 and a thickness of 38; it has been normalized and heat-treated. It is in use at the customer’s site, but its performance is very poor. We want to modify it by welding a support ring with a width of 50 inside it, and then installing our internal components to carry out the modification. Do we still need post-weld heat treatment for the container after this modification? Does the repair clause in 150 apply here? ? Personally, I think post-weld heat treatment is not required; the relevant clause applies. Is it correct?
Heat treatment is required as specified in 7.4.3 for composites. For containers other than 7.4.3, the requirements of Composite 7.4.4 allow for the omission of heat treatment. Well then. What is the material of your container and what are its operating conditions?
It depends on the reason for the heat treatment of the original equipment.
This post was last edited by Clever Xiaoming on 2017-1-6 at 13:10. The medium is explosive, but not of extremely high hazard; the material used is Q345R with a plate thickness of 34, which is why heat treatment is required. Personally, I think clause 7.4.4 is not sufficient either for welding the support rings internally; it doesn’t involve the issue of the depth of repair required! Therefore, is local heat treatment necessary?
For Q245R and Q345R materials, if it can be determined that post-weld heat treatment is required solely due to the plate thickness, then this additional support ring installed as part of the modification does not need to undergo post-weld heat treatment. However, preheating is required for welding this component, and surface magnetic particle testing after welding is still necessary.
In the situation described by the original poster, it is sufficient to weld a support ring; there is no need for heat treatment after welding at all.
I agree with you; as long as the preheating before welding is done properly, it’s fine.
If you already have heat treatment, heat treatment must be carried out again before welding.