Nil Ductility Transition Temperature

Where have you looked so far?

Please list all the searches you have performed, the text books you have read and the knowledgeable trade organizations and experts you have contacted.

This will allow for less duplication of the effort you have already, presumably expended.

I have searched on net but not getting exactly

Well, get going on lyn's list, then!

The telephone is a far better tool to use for research, as it is interactive, immediate, puts one in contact with humans, and cannot be ignored by them.

Try using the industry accepted term "glass transition temperature" instead of some bullcrap your instructor came up with in your google searching.

Both terms are accepted, so I'd search for both.

I did a few searches and understand the problems with searching for this type of info.

Most likely finds were descriptions of papers or books dealing with the subject.

I worked at a ductile iron foundry early in my career and we had to frequently cool it to below 45 degrees for specific gear products that otherwise had a bad tendency to crack suddenly, completely across the diameter of the gear.

Ignore the "old grouches" who contributed almost nothing to your inquiry.

This is a resource like any other on the internet, and most of the time is great for finding others who will help. Do take the advice to list the items searched for. Do you have a specific application/problem. This will not have an exact answer due to the many compositions of the listed materials.

Try searching for images as well as textual content.

Good luck!