PWHT of 1.7380 (ASTM 217-WC9)

[DesertEagle01]

Hello,

I like to adress this post to all collegues who are involved with steels at elevated temperatures like boilers, coloums, etc.

I am working on a very special case where the chamber of a heat exchanger made of 1.7380 (apprx. ASTM 217-WC9) was found to have a crack.

The codes (EN as well as ASME) require this material to be preheated during welding and subject to a PWHT at around 600°C.

For my special case it is impossible to perform the PWHT in the field which would mean the whole HX needs to be disassembled and brought to the workshop.

Now there was some information that with special filler material one might get rid of the PWHT of this material. Is there anyone who has experinece in this area?

Any input is highly appreciated!

BR,
Daniel

 

[kclim]

With regards to special filler, within power generation repairs to Cr/Mo steels with austenitic filler materials (Inconel, 308) without PWHT are not uncommon. The thinking being that the austenitic weld structure affords more ductility and avoids cracking in the base material. I don't believe there is an official standard governing this, and the repairs are normally considered temporary.

Temper bead welding may alleviate the need to perform PWHT, and is recognised by ASME and NBIC. Unfortunately I can't refer you to the exact passages in ASME IX, so you will have to consult the code on the issue yourself.

 

[metengr]

Agree with kclim. Grade WC9 can be temper bead welded (no PWHT) based on Alternative Welding Method 5 in the NBIC. You have the option of using a ferritic filler metal or austenitic filler metal. The requirements for procedure qualification are in ASME Section IX, QW-290.

 

[DesertEagle01]

Thanks for your reply and useful input. Do you know if there are some studies available for toughness and strength of such repair welds?

BR,
Daniel

 

[metengr]

Yes. You will need to search for this information. I cannot post the data.

 

[metengr]

http://documents.mx/documents/smaw-temper-bead-weld-repair-without-grinding.html

 

[DesertEagle01]

Thanks a lot.

Dan

 

[DesertEagle01]

Thanks a lot.

Dan