Cru Forge V - toughness testing re-analyzed

[Larrin]

I wrote up a new summary of the Cru Forge V toughness testing that we previously tested, along with some new details not previously reported. I also wrote a little bit about the design of the steel and how it compares to O1.

http://knifesteelnerds.com/2018/03/26/cru-forge-v-toughness-testing-processing-and-background/

 

[hugofeynman]

So AEB-L is still the king of the hill? Does it need some 0,5% carbon steel to beat it?

 

[jdm61]

What does AEB-L look like at the more common high hardness levels that we are using these days? Also, do you have any numbers comparing the "standard" HT for AEB-L vs your dad's multi-step methodology with the 1700F "low temp austenizing" step?

 

[Justin Schmidt]

Ok so from what my feeble mind can understand: 1550-1700 deg forging temp 1500 deg austentizing with no soak and a 400 deg temper will lead to the best results.
Question: why wouldnt you compare toughness vales at the same hardness steel A is generally always going to be tougher at RC 59 than steel B at RC 63. Or am i missing something? If im wrong or way off base i apologize

 

[Larrin]

Ok so from what my feeble mind can understand: 1550-1700 deg forging temp 1500 deg austentizing with no soak and a 400 deg temper will lead to the best results.
Question: why wouldnt you compare toughness vales at the same hardness steel A is generally always going to be tougher at RC 59 than steel B at RC 63. Or am i missing something? If im wrong or way off base i apologize

In an ideal world we would keep all variables identical other than the one in question. Otherwise we compare the data that we have.

 

[Larrin]

What does AEB-L look like at the more common high hardness levels that we are using these days? Also, do you have any numbers comparing the "standard" HT for AEB-L vs your dad's multi-step methodology with the 1700F "low temp austenizing" step?

That information is not currently available. If anyone is willing to generate the unnotched charpy specimens we can all find out together.

 

[Justin Schmidt]

Makes sense. Hopefully someone submits one with these tests yall are doing

 

[DevinT]

Before the testing, Larrin had to caution me to not just test what I wanted and also look for a specific result(s). I definitely wanted to prove some things. Because of that, Larrin specified all of the forging and heat treating schedules.

Hoss

 

[Larrin]

Ok so from what my feeble mind can understand: 1550-1700 deg forging temp 1500 deg austentizing with no soak and a 400 deg temper will lead to the best results.
Question: why wouldnt you compare toughness vales at the same hardness steel A is generally always going to be tougher at RC 59 than steel B at RC 63. Or am i missing something? If im wrong or way off base i apologize

I wouldn’t say 1550-1700 for forging, potentially it shows an optimum forging temperature of 1700, otherwise it just shows 1550-2000 leads to similar behavior. I can’t say if 1500 with no soak would be best as we didn’t do any “no soak” heat treatments. A 1450F with 10 minute soak looked pretty good with sufficient hardness. It depends on desired final hardness in terms of what tempering temperature to use.

 

[Justin Schmidt]

Ok I got ya, thanks larrin