PWHT a API650 modified tank 1

[littlefish2003]

hi, we are building a caustic 50% storage tank. client asked us to do a PWHT on the whole tank. how do we analyze when tank is heated to 1150 deg F, the plate property change? tank floor is 3/8" THK, shell is 1/4" THK, roof is 3/8" THK, we will be using G40.21 38WT plate. thanks in advance

 

[SnTMan]

littlefish2003, I'd expect no meaningful property changes in carbon steel, but I'd be concerned about distortion of the tank, depending on dimensions.

You might be better off in this forum: forum1452

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Dhurjati Sen]

Dear littlefish2003,

PWHT of the whole tank means PWHT of all the weld joints of the tank. If you think distortion could be an issue, you may go for localized PWHT. Of course, it has to be economical too, as it would take more time for sure.

Tanks fabricated at site are locally PWHTed only.

Choice is yours.

Regards.

DHURJATI SEN
Kolkata, India

 

[mk3223]

Consider to have a PWHT of the whole tank in the furnace, if fitted, for a better temperature control through the heat treatment process, and avoid the potential thermal stress caused by the local PWHT process.

 

[weldstan]

How large is this tank?

 

[0707]

the requirement for PWHT is to avoid caustic embritlement. I suppose it is a small tank. If possible the tank shall PWHT as an all in a fournace. Care shall be taken with provisory reinforcements to avoid distortions.

luis