Super tough super steels??

[scdub]

Howdy folks,

A question for you - how do the “tough” modern super steels (particularly 3V, Magna Cut, and other tough stainless steels) compare head-to-head with the tough carbon steels like 5160 and S7? I understand that they can retain an edge longer, but can they retain their overall shape as well under stress?

I used to believe, mostly through my reading here, that the old school carbon steels were still superior to the “super steels” in terms of toughness (resistance to impact/fracture) at a particular hardness, but recently I’m reading posts that seem to suggest I might be wrong.

So - and this is particularly a question for you metallurgy folks out there - can you describe the comparative toughness of these steels?

Essentially I’d like to know what steels will resist catastrophic failure the best at, say, 58 rockwell.

Or, asked another way: If you made a bunch of “mule” knives at 58 hrc in different steels, which one would take the most abuse before breakage?

Any references or links to scientific articles etc. would be greatly appreciated

Disclaimer: I may not be using the correct terms re: toughness/impact resistance, etc. Feel free to define terms more properly as you see fit.

 

[unwisefool]

Super steel has no real definition but is often used to mean “high edge retention.” Edge retention and toughness are conflicting properties so almost by definition super steels will not have the highest possible toughness.

Where does the surgical steel used on my ninja sword fall under? Bear in mind, it's tactical...

 

[Oldtoolmaker]

In terms of toughness, S7 beats them all, at the cost of edge retention.

These days, I'm less picky then I used to be : CPM Cruwear, 3V, A2, modified A8 (INFI), CPM M4 are all almost interchangeable in my mind, even though they do have corrosion/edge retention/toughness tradeoffs. They all seem to have enough chrome to not corrode in my use. Just got my first S7 knife, we'll see

On the stainless side, AEB-L is my favorite. But don't forget properly heat treated 420HC, way up there wrt to toughness.

Note that I don't worry about fatal blade breakage, and I don't hammer knives into concrete. I'm just lazy sharpening, I hate edge chips.

Roland.

Hi, curious about who uses s7, I knew it as a shock resistant steel I used for mold tooling

 

[ferider]

Hi, curious about who uses s7, I knew it as a shock resistant steel I used for mold tooling

Busse does (“SR-77”).

Mine is custom made ( CPE_Knives ).

 

[Oldtoolmaker]

Busse does (“SR-77”).

Mine is custom made ( CPE_Knives ).

Thanks for the info on that