We are going to replace a column in A516Gr 60 to be clad with TP 304L on top between tray 2 and 3 and from tray 11 to the bottom. The previous column was not clad and it was PWHT because it works in AMINE service. T he purpose of cladding this amine vessel is to prevent wet H2S cracking. During the stress relief of c.s A516Gr 60 plate’s clad with TP304L is there the possibility of carbide precipitation between the carbon steel and the stainless steel? Would it be prudent to PWHT only the A 516Gr 60 plates not clad or we shall PWHT the vessel as a whole, clad and unclad C.S. plates? An answer would be appreciated Regards Luis Marques

Mr Hendrix The carbon steel plates are 13mm Thick with a 3mm thick clad of TP304L .We are going to link by welding these plates to other carbon steel plates 13mm Thick without cladding. For that reason I am afraid that the temperature developed by PWHT on the seam welding between clad an non clad plates could disbound the TP 304L. Maybe the best option is to clad the entire column. The savings on heat treatment will permit that option Thank you for the empathy Receive my best regards Luis Marques