PREHEAT TEMPERATURE

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Manoj Mumbai

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May 21, 2021, 11:49:36 PM5/21/21
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Dear Experts,

The preheat temperature shall not be less than 55 deg. C as per QW-406.1 but  not specified a maximum how much it can be from the temperature noted in PQR as preheat temperature is minimum temperature and interpass temperature is the maximum temperature.
My question , Is there any limitation to increase preheat temperature than mentioned in PQR. suppose PQR temperature is Ambient, say 38 deg. C, can we increase preheat temperature to 204 deg. C.  I have a qualified procedure of P6 material at ambient temperature 38 deg.C now I have to include preheat temperature.

Thanks in advance for your expert opinion.
Manoj.

Kannayeram Gnanapandithan

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May 22, 2021, 1:17:16 AM5/22/21
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Yes based on thickness

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Gerry Lourens

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May 22, 2021, 5:40:45 AM5/22/21
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There are no limits to the Preheat temperature provided that there are no toughness requirements.
If toughness (impacts) are required :
the maximum inter-pass temperature qualified equals the maximum preheat temperature.

Best Regards,

 

Gerry Lourens

Welding Engineer

New Age Engineering Solutions

 

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Kannayeram Gnanapandithan

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May 22, 2021, 7:26:04 AM5/22/21
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Could you give code ref for control of preheat on maximum side

Manoj Mumbai

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May 22, 2021, 11:44:42 PM5/22/21
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Ganesh Muthurajan

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May 23, 2021, 12:21:32 AM5/23/21
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Mr. Manoj, 

Preheat requirements for P6 materials ( martensite stainless Steel). 
As per ASME 31.3 Table  330.1.1
State  the minimum requirement are 200. Deg. C. For all thickness. There is no additional  requirement. We should follow min 200 deg C minimum temperature.  

Ans the inter pass temperature is min 315 deg  C, 

Even your PQR is in ambient temperature.  











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Prem Nautiyal

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May 23, 2021, 4:07:50 AM5/23/21
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Min and Max preheat temperatures are mentioned in ASME Sec II C also for certain consumables.

Regards

Prem Nautiyal 


Kannayeram Gnanapandithan

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May 23, 2021, 10:40:26 AM5/23/21
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Preheat temp maximum restricted only in AWS D1.1 only

ramesh kumar

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Jun 23, 2021, 10:16:07 PM6/23/21
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Dear Manoj,
               Please also refer as mentioned in ASME SEC IX for your query.............
QW-406.3 PREHEAT An increase of more than 55Deg C in the maximum interpass temperature recorded on the PQR. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austentic or P No. 10H material is solution annealed after welding.

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Kannayeram Gnanapandithan

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Jun 24, 2021, 1:44:21 AM6/24/21
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No where mention the restriction on maximum preheat temp as per mention code ASME B31.3, ref 330 and 330.2,,,  and API RP 582, 8 preheat and interpass temp.  Restriction on Max interpass tem only to avoid coarse grain that too for Impact requirements

THANKS & BEST REGARDS,
KG.PANDITHAN, BE, IWE,  CSWIP 3.1,
ISO 9712 Level 2 in VT,
ASNT-Level II in PT,MT,RT & UT,
LA ISO 9001-2015,
International Welding Engineer. 
CONSULTANT-WELDING & QUALITY
Mobile no: +919940739349


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