Dear All,
Greetings.
A Vessel has to be fabricated as per ASME SEC VIII DIV 1. Vessel requires SPWHT as per Client requirment.
A Dished head of material SA 387 GR 12 CL2, Normalized and Tempered - 80 mm Thickness, has been HOT Formed at temperature 920 deg. Celsius.
As per Hot Forming Procedure after reaching soaking temperature of 920 deg celsius and holding for 1 hour, Hot forming operation was performed outside the furnace and immediately after hot forming dished head was put back in the furnace and temperature was again increased upto 920 dec celsisus before transferring dished head in Shop Floor for cooling.
As per ARAMCO Standard Noramilizing and tempering shall be perforemd as seprate operation after Hot forming as per below clause.
13.2.14.1 Heat-treatment, as a separate operation, shall be performed after a forming operation (hot or cold) for any of the conditions listed below. The heat treatment shall be annealing, normalizing, normalizing and tempering, or quench and tempering, as required.
Please be informed that as per hot forming procedure Noramalizing after forming has to be performed at 920 Deg Celsius.
Contractor has not performed Normalizing sepratley after Hot forming. as per reports test coupon has also undergone only ONE Normalizing Cycle.
Please advise whther Normalizing can be avoided as the hot forming was done at Normalizing temperature.
As per ARAMCO requirement Heat treatment cycle for Dished head & Test coupon should be Hot forming + Normalizing + tempering + SPWHT.
Please suggest.
Thanks in advance.
Regards
Asad Azmi
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