RE: [Pressure Vessel] MDMT
Bathula Raghuram (Mumbai - PIPING)
Mr. Masood
Please refer UG20 (in case you are designing as per ASME Sec VIII div1)
Shall be determined based on the mean metal temperature expected under operating conditions (generally given by client/process licenser) for the part considered, If necessary the metal temperature shall be determined by computation or by measurement from equipment in service under equivalent operating conditions.
MDMT will be lowest of operating temperature or atmospheric temperature (lowest possible temperature during entire year where the vessel being installed for operation) and/or any other source of cooling.
A rated MDMT can be found using the rules of UCS 66 to determine the coldest possible MDMT without requiring impact testing (Fig UCS66.2), but this need not be put on the name plate, name plate MDMT shall be a client’s/Design MDMT as described above.
Regards
Raghuram Bathula
From: Pressur...@yahoogroups.com [mailto:Pressur...@yahoogroups.com] On Behalf Of Bayat, Masood
Sent: Sunday, August 05, 2007 3:38
PM
To: Pressur...@yahoogroups.com
Subject: [Pressure Vessel] MDMT
Dear All
Can you help me about MDMT (min metal design temp)? can you help me how I can calculate it for known material and pressure?
Thanks
Masood
__._,_.___
Gireesh Hegde
This is going good. Also the MDMT of the equipment depends on upset / blowout conditions which are short term activities (apart from the lowest temperature of the year in which equip is installed). Members may throw some more light on this since I am much interested to know more.
Now I have one more problem with me –
My client requirement for the fabrication of vessels (as per ASME coded) is “qualify the welding procedure with impact testing at – 45 degree centigrade”. Does it mean that, I should consider the impact testing as supplementary variable in order to restrict the welding parameters like welding position and so on. Or just do impact testing as part of procedure qualification along with the regular relevant mechanical testing and forget about restriction on welding position and other parameters.
Gireesh Hegde
Quality Engineer
Petrofac Engineering & Construction
Petrofac House, Al Soor Street, P O Box 23467, Sharjah, UAE
Email: gireesh.hegde@petrofac.ae
Tel: +971 6 574 0999
+971 6 517 3921 (direct)
Fax: +971 6 574 0099
Web: www.petrofac.com
Gireesh Hegde
Members,
Whether heating rate makes any difference in case of normalizing heat treatment of carbon steel?. Though the cooling rate makes difference on the properties, however I assume there is no restriction on the cooling rate (as long as it is in still or agitated air). I need your opinion.
Also in my opinion, what is important here is to maintain the soaking temperature essentially above the AC3 without any temperature drop below AC3. This should satisfy the normalizing treatment.
Please provide the feedback.
pjo...@technip.com
the type of steel. for normal carbon steel, the changes may not be
significant. But please note that the most important reason to restrict the
heating rate is to avoid big differential temperature between surface and
centre of the item to be normalized. And the heating/cooling rates as well
as soaking temperature/time are normally established by the steel
manufacturers, based on their normal practices. Please try to follow these.
Or else, follow the one in PQR that is already qualified.
Best regards,
Prasad Joshi
Technip AUH - RGX6 Task-force,
"Gireesh Hegde"
<gireesh.hegde@pe
trofac.ae> To
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materials-welding >,
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cc
13/08/07 07:39 PM Subject
[MW:92] Normalizing heat treatment
of Carbon Steel
Please respond to
materials-welding
@googlegroups.com
Members,
Whether heating rate makes any difference in case of normalizing heat
treatment of carbon steel?. Though the cooling rate makes difference on the
properties, however I assume there is no restriction on the cooling rate
(as long as it is in still or agitated air). I need your opinion.
Also in my opinion, what is important here is to maintain the soaking
temperature essentially above the AC3 without any temperature drop below
AC3. This should satisfy the normalizing treatment.
Please provide the feedback.
Gireesh Hegde
Quality Engineer
Petrofac Engineering & Construction
Petrofac House, Al Soor Street, P O Box 23467, Sharjah, UAE
Email: girees...@petrofac.ae
Tel: +971 6 574 0999
+971 6 517 3921 (direct)
Fax: +971 6 574 0099
Web: www.petrofac.com
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