Cooling diagram Duplex stainless steel

[EuroWeld]

Dear All,

Can somebody help me to find the diagram that help me determine the needed cooling rate for duplex stainless steel (A182-F51), Like CCT or phase diagram? Showing melting temperature till room temperature. And can somebody also help me how to find a manner to calculate the needed cooling rate after solution annealing. Suppose we have a forging with dimension 300x300x300mm and we quench it in water at about 20 degree celsius. What is practically possible and what is needed to prevent the growth of intermetallic phases like Nitrides, Sigma an Chi.

All help is appreciated, thanks in advance,

 

[metengr]

Look on page 11

http://www.imoa.info/_files/stainless_steel/Duplex_Stainless_Steel_2d_Edition.pdf

 

[EuroWeld]

I am aware of that article which is very well of my help! But it does not show which phase there is during melting, cooling, annealing etc. I guess ferrite during melt, and like 50/50 during annealing? I want to know how to calculate the cooling rate my self. I guess that without solution annealing the structure will be full ferrite, am I correct?

I hope somebody can help me solve the case above!

 

[metengr]

EuroWeld;
There are several good reference articles and even books on duplex stainless steels;

http://www.springerlink.com/content/2q687764m4452100/

http://www.scientific.net/MSF.638-642.2986

http://books.google.com/books?id=VF...sKrLcSV58Rh9OkmkGgo&hl=en#v=onepage&q&f=false

 

[EuroWeld]

Thanks,

Looks like the information that I need. Do you perhaps have a copy for me of these articles. They are asking a large ammount for it. If not I have to buy.

Kind regards,

 

[EdStainless]

If you splat quench from melt you will get nearly 100% ferrite.
At any practical cooling rate you will get some mixture. The main reason for annealing isn't to fix the A/F ratio but to fix segregation. If you anneal at higher temps you get more ferrite, lower temps more austenite.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[EuroWeld]

Thanks Edstainless,

Can you explain what will determine the exact annealling temperature? Is it volume, chemical composition, client requirements? When we want a 50/50 A/F structue, how to calculate the correct temperature? Most material spec only gives a minimum!


Thanks

 

[bhollands]

How tight is your ferrite range? You state that you need "50/50 A/F" structure but that's not realistic. The minimum solution anneal temperature is to make sure you break up any sigma and other nastiness in the microstructure. You can change the ferrite a bit by changing the temperature that you quench from. In duplex castings it is common to solution anneal at 2150°F and then furnace cool to 1850°F and quench from there.

All of the equations and CCT diagrams are great but eventually you will need to heat treat the material and do a ferrite point count to see if it is going to work.

Bob

 

[MikeMet]

The attachment is something I have had for a while. Hope it helps.

 

[EuroWeld]

Hello Mikemer, Maybe I am not searching correctly but I can not find anything that is of my help! Can you explain what I can find on that website?


@BHollands

Our requirements are 40-60% Ferrite. But I guess the producer tries to reach 50/50 am I correct? My question is mostly related to forging. After forging solution annealing and rapid water quenching. I understand that all requirements has to be cheched afterwards. But what determines the correct temperature for solution annealing?

Is raw material for forging of any influence, means Ingot, Slab, Billet? Maybe manner of forging (ratio)?