How to repair pipe crack for material 20Cr32Ni. 2

[johnlabuu]

Dear All,

Can someone advise me on how to repair the pipe tee with OD760 and 39mm thickness?

What is the best welding method to complete this repair activity and it is required for any PWHT after completing the repair activity?

Appreciate any advice given.

Thank You.

 

[DekDee]

I always cringe when I see posts like this.
A 39 mm exotic material pipe that has cracked and you ask an internet forum as to what to do ?
First thing you should do is hire a Welding Engineer to advise you.
You take information from an internet forum (no matter how well intentioned), conduct your repair, it goes back into service.
Hypothetically, repair fails and people die.
You stand in front of a judge and tell him "well the good folks at eng-tips.com forum told me it was all good"

 

[EdStainless]

You need to find out the root cause of the crack before you do anything.
Hire an expert.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[johnlabuu]

Noted & Thanks for Advise.

Very Appreciated.

 

[XL83NL]

John, you’ve been given the best possible advice on your query. An LPS would be in place, even though the advice may sound like simple. You’re asking really difficult/tricky questions here.

Huub
- You never get what you expect, you only get what you inspect.

 

[Tmoose]

I have no clue if this is your material and situation, but this sounds pretty scary.

https://era.library.ualberta.ca/ite...-6ccfe2b18dc2/Dewar_Matthew_Spring-202013.pdf

20Cr-32Ni-1Nb stainless steel alloys are commonly used in hydrogen reformer manifolds for
transporting hot hydrogen by-products at 750-950C. After long periods of exposure, embrittling
secondary carbides and intermetallic phases can precipitate at the grain boundaries
which can drastically reduce the ductility, and the repair weldability of the alloy. The intermetallic
silicide, G-phase, is commonly observed in 20Cr-32Ni-1Nb stainless steels, and is
prone to liquation cracking during welding operations. G-phase is deleterious to the material,
where a high degree of G-phase coarsening will render the material unweldable.

 

[XL83NL]

Looking back into your post history, you seem to be asking quite some specific questions every now and then on specific (reformer
Like) alloys. Do you ask these out of curiosity and to gain insight? Does the company you work for not have a dedicated metallurgical or welding engineer in place to help and mentor you?
PS: 20Cr32Ni seems to be a (very close) match or equivalent designation of UNS N08811, or alloy 800HT. At such dimensions, that’s something very special

Huub
- You never get what you expect, you only get what you inspect.