CA6NM 2

[lidbasky]

Hi,
Could anybody help me to find CA6NM steel TTT diagram?
I look in Heat treaters guide and I cant find it?

 

[blacksmith37]

Try F6NM (forged): there will be some differences, but there are also differences between heats of CA6NM. It has very good hardenability, but in my opinion, a complex response to HT. (MAY respond to double tempering, cryogenic cooling , etc).

 

[arunmrao]

http://www.scielo.br/pdf/rem/v60n1/v60n1a25.pdf

You can see the ttt curve. Being a soft martensitic steel,fast air cooling followed by double tempering is the normal practice.

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[Guest102023]

CA-6NM has good hardenability to essentially unlimited thickness, but it is sensitive to compositional differences: the final hardness is extremely sensitive to carbon content, and nickel is an important actor in depressing the Ms temperature. I searched my documents but could not find either a TTT or CCT diagram.

A lot of the general literature makes the mistake of lumping it in with other 400-based martensitics when talking about heat treatment, welding, and PWHT of CA-6NM. It is a unique alloy in many respects.

 

[lidbasky]

We tempered our casting in 680 C. Is the retain austenite harmful for mechanical properties?
I need TTT diagram for CA6NM Cast steel.

 

[blacksmith37]

Brinstoner, yes! Thats what I was trying to say, more data in ASTM ATP 756,and it is the only alloy that MR 01-75 allows non-standard hardness conversion. Lidbasky; you may need a metallurgist.

 

[lidbasky]

I am metallurgist but I need TTT diagram for finding Ms & Mf .....

 

[lidbasky]

Is retain austenite in CA6NM harmful when part working in high temprature?

 

[metengr]

No. The problem is upon cooling from high service temperature to lower temperature and the transformation to unptempered (new)martensite.

 

[metengr]

Let me revise what I stated moments ago... if the component is continually operating where creep deformation is a concern, retained austenite would certainly be a problem as well as elevated temperature strength properties.

 

[lidbasky]

Thank you for your reply Metengr. I get the diagram that Arunmrao give its link, but its carbon content is very low about 0.02%.I need some reliable document about TTT diagram to disscuse with my purchaser. I studied Atlas of TTT diagrams but i couldnt find it.