Call for Charpy toughness samples

In another thread reporting some of our initial charpy toughness testing, we got a couple offers for samples for toughness testing. I would be happy to test more samples for the benefit of everyone. While we might not be able to test everything, I am open to taking more samples to compare. There is very little toughness data out there, especially when it comes to comparing between different manufacturers. I would not be charging for the toughness tests, but anything that we measure will be shared with others.

The sample dimensions would need to be as follows:
2.5 x 10 x 55 mm, with 55mm being in the rolling direction. Samples would have to be ground on the 4 main surfaces (less critical on the ends), and parallel, likely requiring a surface grinder or other precision machining tool.

If anyone is willing to heat treat and machine samples for testing, please suggest in this thread what steel(s) and heat treatment(s) you would like to do. Everything we have done so far has had a liquid nitrogen treatment after quenching and prior to tempering so that we can eliminate the effect of retained austenite, so I would prefer that that step is added on other specimens, unless conditions both with and without cryo are provided.

Current tests that have been performed:


Ideal hardness is 60 Rc, even better is a range from 58-64 Rc. Steels we would like to add (incomplete list):
M390/20CV at 60 Rc
S30V
S35VN
S90V
S110V
Vanax
Elmax
440C
ZDP-189
Micromelt XHP
Conventional XHP
Conventional 154CM
N690
VG-10
14C28N
12C27
Nitro-V

3V
4V
Vanadis 4 Extra
Vanadis 8
10V
CPM-M4
M2
A2

52100
O1
1084
1095
15N20
5160
L6
80CrV2
O7
1.2519
1.2442
1.2562
F2
Blue 1, 2, Super
V-Toku 1, 2

 

The ASTM standards don't seem to have anything about required finish. All I have found is stuff about being free from machining marks or scratches. The samples so far were finished at 150 grit. A hole is allowed, it would need to be near the end of the sample as they break in the center.

Edit: I found in the ASTM standard a requirement of 2 micron Ra, which is somewhere around 70 grit. Higher grit finish is better, of course.

 

Keep the different conditions in separate bags with an appropriate label. Include a sheet that includes all relevant details about the heat treatment of each.

 

Sure, let's discuss in this thread what steels and heat treatments you would like to do. That way people can see what has been offered already. And if I decide not to test them I can say why for everyone to see.

 

As long as thy follow the simple specifications, whatever we test will be directly comparable to steels tested earlier, including AEB-L and Cruforge V.

 

I hope you get the furnace back up soon!

 

It’s possible that it will affect it of course, both in terms of your forging and heat treating procedure as well as the welding. It won’t be breaking along the weld, though, so that impact should be minimal.

 

I will not accept any money. If anyone wants to offer material, heat treatment, or machining that would be helpful.

 

The best way to do it is to test hardness with a sacrificial coupon heat treated along with the others. You can get away with hardness measurements on the ends, however.