PWHT needed on Insert Plates? STORAGE Tank Repair under API 653

[PINTAIUS]

Good day to all, fellows

We are repairing an old Storage tank, in which we are going to include two new courses from the bottom, desmantelating the two upper ones.

The material of the shell is A 283 Gr. C, very difficult to find at the moment, so I am going to use S275 Jr (thickness of the lower course is 23 mm). No problem up to this point, but I have a doubt.

I must close all the connections in the first course, and I am going to use insert plates (not *****es). The S275 Jr. is a Group IV, and requires PWHT to all the connections with reinforcement plate but, can we consider an insert plate as reinforcement plate?

In my opinion, it is unnecessary to make PWHT because the plate will be welded instead other plates (different materials, but according to ASME, it is a non essential variable because all of them are P1).

Is the first time on several tanks that I have made myself this question.

Any Help?

Thanks in advance

[adamjin]

Which standard are you referring to for the tank repair? Nowhere in API 653 is it mentioned regarding heat treatment during repair unless welding over 1 1/2" plates to 200 F preheat

I suggest you refer to API 653 section 9. If you want to use an insert plate to cover the hole than it must confirm to minimum size of 12" or 12t. Also bear in mind, minimum weld space requirements.

Alternatively a ***** plate can be used after removal of nozzle and its reinforcement plate. Also the required provisions of API 653 need to be followed.