PWHT on air cooler

[kangar20]

in the air cooler heat exchanger we have to doing PWHT on header but i have to weld tube to tube sheet (strength or seal weld)and as you know we shan't done any welding after pwht. Please guide me ho to solve this problem.

 

[metengr]

No enough information on exactly what you are trying to accomplish. What is the sequence regarding fabrication welding? What is the code of construction? What are the materials?

 

[kangar20]

thank you.
the material of plate is carbon steel sa 516 70 (thk 34 )
the material of tubes are sa-179
and per API 661 we shall be doing PWHT on headers .

 

[metengr]

Why can't you perform PWHT at the end of fabrication, e.g., after tube to tubesheet welding?

 

[sharmass]

For the materials and configuration, PWHT is not required for Tube to Tube Sheet joint.
Headers can be PWHT separately and then assembled with tubes.
API 661 requires PWHT of headers and not tube to tube sheet welds

 

[kangar20]

very thank you
but in the shell and tube heat exchanger that we require pwht and tube to tube sheet joint is "seal or strength" weld , i don't know what am i doing. please guide me for this problem.

best regards

 

[metengr]

Find someone locally to help you, this is not the place to learn ASME Boiler and Pressure Vessel code.

 

[sharmass]

Heat treatment is based on weld thickness and not base metal thickness. whether it is seal or strength weld, PWHT is not a requirement.