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Re: [MW:25452] Pre heat -Press. vessels

there is a huge misunderstanding regarding the non essential variable "Preheat Maintenance". What is meant by the Code is the keeping of the preheat temperature after the completion of the welding and until the performance of the PWHT.
Preheat maintenance according to the Code is not identical with continuous heating during welding

2016-09-23 20:38 GMT+03:00 Kumar <sk7920541@gmail.com>:
Dear Experts,

I would like to have a discussion regarding "pre- heating & its
mainatances" for aPressure vessel weldings ( ASME SEC. VIII DIV.1,
shell thickness -55mm & dish end -65mm, material SA 516 Gr.70, vessel
length -18mtr & ID-3mtr). WPS is calling for pre-heating of 100 deg.
C.(maintainace required for joints above 25 mm thickness)  project
location - GCC.

Welding processes - LS & CS - SAW. Nozzles- SMAW.. since due to the
high ambient temp. of around 35-40 deg. & due  to practical
difficulties, the welders could only maintain pre-heating while they
starting welding & not during the welding ( specially on the other
side of joints). the client insisting for continuous heating during
welding.

I want to request for the opinions from members how far pre-heat is
crucial in GCC environment especially in CS materials.

Thanks in advance,
Kumar

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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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The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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