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Re: [MW:25229] Reg. post heating for low alloy steels

By Materials & Welding
correct it is not the same, but the only way to handle post heating in the frame of the ASME Code is to handle it as preheat maintenance. Remember that it is a supplementary essential variable

2016-08-07 15:08 GMT+03:00 Kannayeram Gnanapandithan <kgpandithan@gmail.com>:

Preheat maintenance is slightly different from post heating( dehydration, hydrogen bake out). Preheat maintenance is a non essential variable. Post heating is generally good for lowalloy/Cr-Mo steel to avoid HICC.


On 07-Aug-2016 3:40 pm, "George Dilintas" <dilintas@gmail.com> wrote:
In the BPVC ASME Section IX there is a variable "Preheat Maintenance". This is the variable which applies in your case. It is up to you do define the value. The issue is that this variable is a supplementary essential one, i.e when impact test is required, then the PQR has to be qualified with this variable. If the value of temperature is reduced then a new PQR is necessary.
PWHT is possible after welding if you dont remove insulation and you raise the temperature as per B31.3 requirements 331.1.4

2016-08-07 5:33 GMT+03:00 Prasu Cutie <pracuty@gmail.com>:

Dear experts,
We are going to start pqr for low alloy steels i.e. A335 Gr P11, P22, P5, P91 etc, it suppose to be post weld heat treated immediately  after welding. As per literature if pwht is not possible immediately  after welding, intermediate PWHT recommende .i.e pos heating.
Now the question is is there any code reference for the same? What is the heating time n temp???
The codes we r following  here are shell dep's n asme b 31.3
Project: refinery

Awaiting for your reply

Thanks n regards
Prasad
0096594122634

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Dr. Georgios Dilintas,
Dipl. Ing. In Aeronautic and Space Engineering
Ph.D in Mechanics of Solids - Computational Mechanics
A.I.S, A.N.I, IRCA Lead Auditor
Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

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Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

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