Its all depends ;
- Experience of person / company responsible (carrying out) PWHT in modular furnace
- Construction of modular furnace (proper and enough insulation to prevent heat loss
- how accurately one can build furnace without any openings / leakage (except opening with damper to control the air flow / exhaust)
- Nos of burner and burner location
- Circulation of hot air (again no of burner and location and blower capacity/position is important)
- Placement and Nos of thermocouple (thin / thick parts will have variation of 20 -80 deg C difference
If all the care taken for the above points then you can considered modular furnace as good as permanent and go ahead without any hesitation.
- Thickness of part vessel to be heat treated (as the curnace efficiency will not be same as permanent furnace, time to penetrate thickness may take more time (1-1/2 hrs for 30 -50 mm thick material
In my opinion, internal firing would be better option with better controls if not much internals (which may hamper the uniform heating).
Regards.
--
C. K. Purohit
Eng-Tech Weld1
Sr Welding Inspector
-- - Experience of person / company responsible (carrying out) PWHT in modular furnace
- Construction of modular furnace (proper and enough insulation to prevent heat loss
- how accurately one can build furnace without any openings / leakage (except opening with damper to control the air flow / exhaust)
- Nos of burner and burner location
- Circulation of hot air (again no of burner and location and blower capacity/position is important)
- Placement and Nos of thermocouple (thin / thick parts will have variation of 20 -80 deg C difference
If all the care taken for the above points then you can considered modular furnace as good as permanent and go ahead without any hesitation.
- Thickness of part vessel to be heat treated (as the curnace efficiency will not be same as permanent furnace, time to penetrate thickness may take more time (1-1/2 hrs for 30 -50 mm thick material
In my opinion, internal firing would be better option with better controls if not much internals (which may hamper the uniform heating).
Regards.
On 30 July 2010 15:48, suresh venkat <atozsuresh@gmail.com> wrote:
Dear all,we have several equipments of diameter 5mts & above & length 30 mtrs & above. Our specs calls for PWHT in an enclosed furnace.some of our fabricators expressed inability due to furnace size restrictions& informed us that use of Temporary Modular furnaces will pose risk to Quality of final product.I need your advice on the following1. Is doing PWHT in modular furnaces will create any problems to the equipment (in terms of quality)2. can the temperature be properly controlled3. Pwht can be performed properly without overheating or Under heating.thanksSuresh--
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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.
--
C. K. Purohit
Eng-Tech Weld1
Sr Welding Inspector
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
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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