Applicability of Iron Carbide Diagram

[RV Mannikanti]

Hey experts,

Can any one tell me, whether the Iron Carbide diagram is applicable to Stainless steel or not.

If it is applicable Max %C in Stainless steel is 0.08 and there are different types of stainless steels sch as Ferritic, Austenitic Martensitic stainless steels.

Please explain me.

Raghuvamshi

 

[EdStainless]

No is the short answer.
Sort of for lean ferritic/matensitic alloys, but the Cr shifts things a lot.
Why? What do you want to know?
I work off of pseudo-three component phase diagrams, where one of the axis is actually a combination of elements.
And I have some curves for some specific alloys (super austenitic and super ferritic).

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P.E. Metallurgy

 

[arunmrao]

You need Fe-C-Cr phase diagrams with differing Ni contents.

 

[EdStainless]

And depending on which alloys you are working with N, Mn, Mo, Si, Cu, and a few others.
C-Cr-Fe (mine are all filed alphabetically) will handle basic ferritic/martensitic alloys.
And I used to have ones for cast austenitics that was a series of C-Fe diagrams each for a different fixed Ni, N, Si, Mn level.
You had to interpolate between them.

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P.E. Metallurgy

 

[RV Mannikanti]

Thank You Sir's,

In that case, is there any phase diagrams that we can relate to Stainless steels? I just started working as a Welding Engineer and wanted to know what could be its structure and behavior during welding and cooling process.

Further to our discussion could you please help me with the below query:

1) What is actually happening in Tempering of steel, i mean in Micro structural ways, we all know that tempering of steel could result in reduction of hardness and tensile strength with an increase in Impact strength.

Is there any crystal structure change happening during Tempering?? (From BCC to FCC)

Please help with these.

 

[weldstan]

Tempering of carbon and low alloy steel below the lower critical temp does not change to FCC; however it can change the body centered tetragonal structure of martensite, which may be formed during cooling from the welding temp.

 

[EdStainless]

The other issue in austenitic alloys is the residual delta ferrite in the welds.


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P.E. Metallurgy

 

[arunmrao]

ASM has several online tutorials. Suggest you enroll and gain knowledge.

Come back if you still have concerns.

 

[RV Mannikanti]

Could you just share me the link sir

 

[EdStainless]

Start here:

https://www.asminternational.org/le...aced/-/journal_content/56/10192/1961775/CLASS

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P.E. Metallurgy

 

[RV Mannikanti]

Sir,

What are the crystal structures that may form during cooling from welding ???

 

RV Mannikanti,
You say you are just starting as a welding engineer, but you are seeking a basic metallurgy primer.
What has been your academic training to date to prepare you for this undertaking?

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

 

[RV Mannikanti]

I am a Mechanical Engineer and i just have some basic knowledge on metallurgy.

As i said i just started working as a Welding Engineer. Need to learn a lot about welding metallurgy and materials behavior at different situations. That's why i am seeking all those answers.

It would be helpful if you can share the Welding Metallurgy Hand book, if any u have..

Raghuvamshi

 

[weldstan]

The AWS has many volumes of welding handbooks. I suggest becoming a member.

 

[EdStainless]

RVM, depending on where you are you have better luck working with TWI (UK) or AWI (Australia) or some of the other associations world wide.
One thing that you haven't mentioned is which alloys you are working with.

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P.E. Metallurgy

 

I don't want to discourage anyone leaning, but welding engineering is not something you just decide to pick up along the way. Everybody 'knows something about welding', but becoming a proper WE is a lifetime commitment. Don't buy handbooks, attend some actual courses.

As the saying goes, 'a little knowledge is a dangerous thing'.

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

 

[Dhurjati Sen]

Buy "Introduction to physical metallurgy - by ‎Avner " The language is lucid and its easy to understand. You would get answers to all your questions. The price is quite affordable.

DHURJATI SEN
Kolkata, India