Skip to main content

RE: [MW:6278] Satbalising (Treatment of SA321H

By Materials & Welding

Hegde Sahib

 

i)What is the significance of stabilizing treatment at 950-980C  with soaking for 2 hrs and cool in air   even after solution annealing at 1050C followed by water quenching? Why Stabilizing treatment is necessary for H grade Ss and not in L grade SS ?

The ASM Handbook states that 'the stabilising anneal.. consists of holding at 845-900°C for up to 5h, depending on section thickness', but does not give methods of cooling or cooling rates. The Metals Handbook suggests a stabilising treatment of 2-4h at 870-900°C followed by rapid cooling to precipitate all possible carbon as Ti or Nb carbides and subsequently prevent Cr carbide precipitation. This is especially needed for H grades of stainless steels.

 

ii) Is there any  affect on properties  if we do not go for Stabilizing treatment

Yes, in effect with no stabilised treatment, you would expect that Cr carbides are formed (rather than Ti or Nb carbides) thereby reducing the corrosion resistance (primarily).

 

iii)What will be the microstructure of Stabilized 321H steel as against only Solution annealed

See above, you will have Cr carbides in the grain boundaries, leading to depletion of Cr in a narrow band around grain boundaries. Hence the requirement for IGC practice E.

 

Rgds

 
Sayee
 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of PB HEGDE
Sent: 03 August 2010 05:07
To: materials-welding@googlegroups.com
Subject: RE: [MW:6271] Satbalising (Treatment of SA321H

Dear Friends

My query was  particularly for H grade  321 i.e. 321 H

i)What is the significance of stabilizing treatment at 950-980C  with soaking for 2 hrs and cool in air   even after solution annealing at 1050C followed by water quenching? Why Stabilizing treatment is necessary for H grade Ss and not in L grade SS ?

ii) Is there any  affect on properties  if we do not go for Stabilizing treatment

iii)What will be the microstructure of Stabilized 321H steel as against only Solution annealed

 

 

Regards

 

Hegde p.B.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Shashank Vagal
Sent: Monday, August 02, 2010 11:46 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:6262] Satbalising (Treatment of SA321H

 

I am confused-
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.


--- On Mon, 2/8/10, PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> wrote:


From: PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com>
Subject: Re: [MW:6257] Satbalising (Treatment of SA321H
To: materials-welding@googlegroups.com
Date: Monday, 2 August, 2010, 9:20 PM

Sir

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.











--
>
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.
>


PREM S NAUTIYAL
CELL : 9820313278

--
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.

 

--
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.

--
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.

Comments

Post a Comment

Popular posts from this blog

Re: [MW:34105] SA266 GR4N 4 Cycle SPWHT

By Materials & Welding
Hi,  You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this.  Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime.  Again, these simulated no. Of cycles shall be specified in MTC.  The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case).  One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example.  In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...
Post a Comment
Read more

Materails FAQs

By Materials & Welding
Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...
21 comments
Read more

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

By Materials & Welding
Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change.   Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...
Post a Comment
Read more