DBTT Ductile Brittle Transition Temperatures Tables 2

[FeldmanWill]

Does anyone have Ductile Brittle Transition Temperatures Tables for steels. I found one on the web but not sure if I can trust.

Particularly I'm looking for a material that becomes brittle at -40C(F).

Thank You in advance

 

[metengr]

This information is available in various reference materials that would require purchase or at a technical library. If you looking for brittle fracture behavior something like a 1050 carbon steel supplied hot rolled (with no heat treatment) will likely have 2-5 ft-lbs at -40 deg C. There are other materials as well that can exhibit brittle fracture behavior (less than 5 ft-lbs at -40 deg C).

 

[FeldmanWill]

Design calls to hold 230lbs in ductile region which I can easily calculate. And yield strength to drop to hold only 150lbs at -40C(F) which I can also calculate if I get different materials yields at that temperature.

Is that something that do-able in a sense can force be controlled in brittle region or once it goes into brittle it cracks at any force?

Sorry, a little novice with brittle properties.

 

[metengr]

If a material is in the brittle fracture behavior regime this indicates it is notch sensitive. Application of a tensile stress below yield can result in sudden crack propagation in the presence of a crack or flaw. Beyond this it is hard to quantify a threshold tensile stress.

 

[EdStainless]

Most materials have higher strength at low temperature than at RT.
How quickly material get brittle also is a variable.
What toughness do you need? What is the shock or impact loading that are working with?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[FeldmanWill]

I have experimented with Delrin and at room got 225 lbs pull and at -40 it was 255 lbs
I have experimented with Aluminum and at room got 275 lbs pull and at -40 it was 285 lbs

I would like to find a material that will do the opposite go from 225 to say 150 lbs.
The only physical property I have researched that gets weaker with colder temperatures was brittleness.
The system is a continuous pull so there is really no shock, actually there is but I'm not using it in my calcs. but I can start to.

Looking for a chart of 1010-1080's steels their DBTT, may be strength on y-axis and temp on the x-axis.


William

 

[EdStainless]

Materials get stronger when colder, all of them do this.
There are some that change less.
If you get into the brittle region then you will either have higher strength (when it doesn't fail) or zero strength (when it cracks).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[FeldmanWill]

metengr and Ed thank you.

That's kind off the feeling that I had, thank you for confirming that.

Still a little itchy to try it out in the lab. I found a goofy DBTT chart that at -40C(F) between 1040 and 1060 steels enter brittle zone, can that be confirmed. I don't have smart metallurgical books.

William