Krish Internal lining - Resco with SS 410 hexmesh - may develop local voids / disbonding during PWHT after repairs due to external heat given to the P 11 cyclone shell. Though not related to this particular problem, industry users who have internal refractory lined vessel or piping have experience of voids or surface crack develop in refractory due to external heat. Industry users have experienced this problem when external heat is supplied due to PWHT or fire from gas leakage through voids or cavities or surface cracks in refractory lined primary reformer inter-transfer piping or in secondary reformer vessels or piping. If hot spots do not develop at the particular weld repaired areas then you can assume that no voids or surface cracks had not developed due to localized PWHT of P 11 barrel cyclones. If hot spots develop during operation, then external steam or air quench is resorted by users in such a situation to avoid external P 11 transfer piping does not have a run away temperature excesses other than designed (insulated due to Resco) temperature limit conditions. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Dec 21, 2007 E-mail: nishi@vsnl.com >We have carried out weld repair in the FCCU Reactor primary >cyclone barrerl made up of P11 material (12.5 mm thick) >which has been provided with Resco AA22S abrasion resistant >lining on SS410 hexmesh.After weld repair we are planning to >carry out SR without removing internal lining. Is there any >possibilility of hexmesh debonding during/after SR if >lining is not removed?I request our forum member to share >their experience and their suggestions. > >with advant thanks,