Seeking help with high toughness steel

[pkostka]

Hello,
I'm seeking help with material selection for a high impact speed application. We are currently using HRC 54 S7 as both impactor and target. The impact velocity is near 50m/s and we find occasional brittle failure a serious issue. I'm wondering if anyone has suggestions as to an alternative. The design life if fairly low so fatigue is not of great concern, there are no corrosive threats and temperature generally room temperature or higher.

Any insight on alternate alloys, similar applications, or consultants who specialize in related topics would be greatly appreciated.

Thank you.

Peter

[Studiot]

Difficult to answer this since you haven't fully described the application.
Which is subject to brittle failure the impactor or the target?
And which is important?

How hard does the steel need to be?

Are you tempering the target a tad more than the impactor?

read here

http://www.britishblades.com/forums/archive/index.php/t-102360.html

[pkostka]

Hi Stdudiot

The target is subject to failure at this point.
The steel needs to yield around 1.9GPa
Right now both target and impactor receive the same heat treatment ... in my mind at least, both are identical, do you think one can behave differently ?

[Studiot]

in my mind at least, both are identical, do you think one can behave differently ?

The stress distribution is highly shape dependent.

I would still try extra tempering for the target.

Otherwise you might have to go to tank armour steel. This is highly ductile, although strong.