Solution annealing and quenching

[purode333]

Dear experts,
As we Know that, quenching is process of rapid cooling.
Annealing is the process of heating to particular temperature and allowed to cooled in furnace.

My query is for stainless steel, normally done solution annealing, In stainless steel also we do the Rapid cooling then why we say its solution annealing?
why not say only a quenching?

Or solution annealing is only the term for the stainless steel?

Can we say that solution annealing is same as a quenching?

 

[metengr]

Your probably getting confused because the term annealing is used in addition to solution, actually solution annealing is also referred to as solution treatment. This is used for heat treatment of certain metals to remove past forming strains and to dissolve certain elements into solid solution. As part of solution annealing treatment you want to rapidly cool to retain elements in solid solution to improve corrosion resistance or to set the stage for further hardening by aging treatment.

Quenching on the other hand has been around since steel was introduced and is a heat treatment term used to rapidly cool for purposes of hardening the steel.

 

Annealing can have different meanings for different alloy systems. Quenching has only one meaning.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

There are other anneal processes for some stainless grades.
For most austenitic stainless alloys when you say anneal you are implying solution anneal. These should only have one phase present.
Grades that are stabilized (321, 347, 439 and so on) should be annealed carefully. If you go too hot and dissolve the stabilization phase then you have damaged the alloy. This can be repaired by giving the a stabilization treatment, the temp depends on the alloy.
The ferritic alloys are very sensitive to grain growth, but these also should be single phase when you are done.
The duplex alloys are fairly sensitive to anneal temperature as it will change the balance between the austenite and ferrite phases, and change their composition.
We don't bother calling the cooling quenching because expect for a few cases (superferritic and superduplex alloys) the cooling rate required to prevent the formation of detrimental secondary phases is not all that fast. Normally a forced gas cooling is adequate.
None of these grades can be 'stress relieved', if you need to remove the effects of cold work then you are going back to the standard annealing temperature.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[arunmrao]

@ purode 333,

On a lighter note Metallurgists have an uncanny knack to complicate simple facts and then make a life time living out of it. ( pun intended).

You might also refer to an interesting discussion about Metallurgist in this forum. This might also jog the memories of all the long time members.


"Definition of a Metallurgist "

http://www.eng-tips.com/viewthread.cfm?qid=247233

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

"Definition of a Metallurgist"

You say it like it's a bad thing!

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[pradipgoswami]

Prode333,
Please refer the following links which I hope will clear your doubts to certain extents:
1.

https://www.azom.com/article.aspx?ArticleID=1141

2.

https://www.asminternational.org/documents/10192/23555666/ASM+Subject+Guide_HeatTreating.pdf

3.

https://www.asminternational.org/do...mple.pdf/7c5e4830-b443-4c71-a8c8-1a85c5b39dc5

In the context of all stainless steels the alloying elements are the keys,which expands or contracts the Gamma Loop. Nickel is the prime element which prevents any phase changes in 300 series steels.
300 series stainless never experiences phase transformation down up -196 DegC. It's all along austenitic even from the solution anneal temperature right down to cryogenic temperature. Hence the only applicable heat treatment for these alloys is Solution-Annealing. While these steels are soaked at 1000 deg C and above all alloying elements goes in the solution and remains there without any precipitation while quenching. This imparts the best mechanical and corrosion resistance properties to 300(typically 18/8, Cr/Ni) series of steels.
Some grades of S.S say martensitic stainless (13/4 ,Cr/Ni ) undergoes phase transformation upon quenching.
You may read and interpret yourself after reading the above references.
Thanks

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[Dhurjati Sen]

Dear purode333

It will be better to consult a book on Physical Metallurgy by Avner.

Dear metengr,ironic metallurgist, EdStainless & pradipgoswami,

I am just 4 months to this forum and you all are very very seniors to me. I have found that recently the quality of the questions have really deteriorated. Some guy wants to know interview answers, some is on the look-out of code loopholes and others ask questions that are being taught at college. Being a Metallurgical Engineer, I am really impressed by your posts and it makes me sad that often they are not appreciated / understood.

Maybe, Metallurgical Engineers are really a dying breed!

Regards.

DHURJATI SEN

 

[pradipgoswami]

Dhurjoti,

Thanks for your comment "Metallurgical Engineers are really a dying breed". It's not a dying breed, it's the discipline one only remembers when someone is in dire straits..
Regards.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299