ductile iron heat treating

[valv]

I need to perform heat tension of ductile iron grade 120-90-02 at 1100 deg F. for 4 hours, my question is would the mechanical proterties change after heat tension? Thank you for your help.

 

[arunmrao]

Heat treatment of ductile iron is done to achieve the mechanical properties. You are trying to produce high strength ductile iron. Based on the section thickness of the castings you will need fast cooling followed by tempering. The desired matrix will be bainite. Please refer to

http://www.ductile.org/

for further reading.

 

[valv]

arunmrao

Thank you for your reply, I've checked out the website you provided and noticed that tempering reduces residual stresses which is exactly what I want to achieve however, at same time, it would reduces the strength of ductile iron which I dont want to happen. You suggested fast cooling followed by tempering, do you mean water cooling?

Also, what is the critical temperature of ductile iron? I apologize for these simple question but I'm new in the ductile iron area, any suggestions will be appreciated.

Thank you