Hi
// 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.//
Generally the necessary heat treatments shall be applied after the specific fabrication process. Here the dish end heated to 920 deg C for ease of fabrication and as part of fabrication and could not be considered as heat treatment. The heat treatment if any shall be done separately followed by fabrication.
// Contractor has not performed Normalizing sepratley after Hot forming//
Normalising shall be done after forming as a separate process. After forming, the dish end shall be brought to at least 425 deg C and reheated to normalizing temperature. ref UCS-56d1.
// as per reports test coupon has also undergone only ONE Normalizing Cycle.//
The test coupon also shall undergo the same heat treatment cycle as required for the final vessel. (here the hot forming cannot be considered as heat treatment and can omit for test coupon.) Ref UCS-85(c)
// Please advise whther Normalizing can be avoided as the hot forming was done at Normalizing temperature. //
Hope the above clarifies the situation.
BR
M.Vijayan
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of asad azmi
Sent: Monday, February 06, 2012 9:59 AM
To: materials-welding@googlegroups.com
Subject: [MW:13615] NORMALIZING OF DIHED HEAD AFTER HOT FORMING
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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