Grade 321H is a modification of 321 with a higher carbon content, to provide improved high temperature strength.321H has higher hot strength, and is particularly suitable for high temperature applications i.e upto 800 degree C.
Solution Treatment (Annealing) which involves heating to 950-1120°C and cooling rapidly is for achieving maximum corrosion resistance.
Stabilising - heating to 870-900°C for 1 hour per 25mm of thickness and air cool.
Stabilisation is recommended for most severe service conditions (above 425°C) and particularly for material annealed at the upper side of the annealing temperature range.
Note that these grades cannot be hardened by thermal treatment.
Regards
Prem Nautiyal
On Mon, 02 Aug 2010 16:50:20 +0530 wrote
>
Dear Friends
Request you to share information
We have a material of SA321H
Specification calls for
The plate should be Solution annealed i.e. Heat to
1040C quench in water after adequate soaking time , and followed by stabilizing
treatment like heating to 900-950C with holding for 2 hrs and cool fast need
not be quenched in water
However This plate to be tested for IGC Practice
E
II want to know
i)
What is the significance of Stabalizing treatment once
it is solution annealed by Water quenching?
ii)
Why it is recommended to cool by Air ( need not be
water quenched)?
iii)
Why it is in H grade only?
Regards
Hegde P.B.
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PREM S NAUTIYAL
CELL : 9820313278
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