Here is a good article on knife steel!

Kestrel

Flashaholic
Joined
Oct 31, 2007
Messages
7,354
Location
Willamette Valley, OR
Thanks for the link; I generally look at these articles with a bit of technical skepticism (and while wearing my "Materials Engineer" pointy-hat), and the normal disappointment didn't take long;

----------
Hardness in knife steels is often referred to as strength
Don't know as much about knives in particular but the above is technically incorrect.

[Toughness] also defines the steel's ability to flex without breaking
Metallurgically speaking, not even close to correct - hard to even begin to go over all the reasons why this is wrong.

Also, the measurement of toughness is less standardized as hardness.
Oh my goodness; :duh2:
https://en.wikipedia.org/wiki/Category:Hardness_tests <- fruit salad
https://en.wikipedia.org/wiki/Fracture_toughness <- /way more/ standardized
Fracture toughness (technically, the only true kind of 'toughness') is much more straightforward than 'hardness', which is incredibly difficult to pin down.

Abrasive wear comes from softer surfaces coming in contact with rougher ones.
(emphasis added)
Huh ?!?!? :confused:
----------

So of the five bullet points to lead off the article, three of the four technical ones include major misstatements; pretty typical really.
 
Last edited:

Kestrel

Flashaholic
Joined
Oct 31, 2007
Messages
7,354
Location
Willamette Valley, OR
Going into hardness vs. toughness in a bit more detail:

-----
[...] hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity.

Fracture toughness [...]
The linear-elastic fracture toughness of a material is determined from the stress intensity factor (
2b76fce82a62ed5461908f0dc8f037de4e3686b0
) at which a thin crack in the material begins to grow. It is denoted KIc and has the units of
28f5b240d5d819866ce7bca262fbca458d10b4a5
or
f8e157f054a7dc73871cd1c63a56ab2665a93c5f
.
Plastic-elastic fracture toughness is denoted by JIc, with the unit of J/cm2 or lbf-in/in2, and is a measurement of the energy required to grow a thin crack.
[...]
Fracture toughness is a quantitative way of expressing a material's resistance to brittle fracture when a crack is present.
-----

For the author to state; "the measurement of toughness is less standardized as hardness", is exactly wrong; please allow the submission of the above info for support.
 
Last edited:

kelmo

Flashlight Enthusiast
Joined
Aug 27, 2004
Messages
3,092
Location
Sacramento
Hey Raptorman!

How's this, steels are like cuts of meat. The cheaper cuts can be quite tasty if prepared the right way. You just have to "temper" your results! HA-HA.

At least the article gives you a reference point on why knives cost so much. Blame it on the steel selection. But who am I to judge, I once paid $300 for a flashlight!

kelmo
 

Woods Walker

The Wood is cut, The Bacon is cooked, Now it’s tim
Joined
Jun 8, 2008
Messages
5,433
Location
New England woods.
Overall I depend more on the manufacture or craftsman than the actual steel in my decision making process though at times have special requirements. Depend even less on articles about knife steels, no insult intend to the OP. I know Wolf Creek Forge, BHK, LT Wright (I think Peters does both unless mistaken) and even on the cheap knife side Jeff White will properly heat treat the steel.

For example this is 1095 which is a tool steel. I would take a 1095 knife made from someone who knows what they're doing over a botched wonder steel knife. Aw heck been on outings and seen 300 dollar knives blow out chucks of metal over stuff a SOG and Mora had little problem with. Why? Because they failed in the treatment during manufacture.

 

RSMJR87

Newly Enlightened
Joined
Dec 29, 2017
Messages
5
Location
CA
Thank you for the link. I own some 154CM, ELMAX, and 1095. I want to get my hands on some CPM-20CV now.
 
Top