440C vs. 420HC Scratch Resistance

TAH

TAH

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Jul 3, 2001
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My son and his friend have a 102 and 105 with 420HC blades. They use these knives mostly (and properly) for general whittling of hot dog sticks and such on our backpacking trips. They never abuse the knives in anyway. I've noticed that both of their blades are scratched up quite a bit from just whittling wood, but my 105 with 440C doesn't show any of this excessive scratching from doing the same type of work. Is 420HC more prone to scratching than 440C?
 
Is the 105 polished finer? Perhaps the higher chromium content helps to resist scratching. DM
 
All knives have basically the same Buck satin finish.

Has anyone else noticed easier scratching on 420HC blades?
 
Of the used 440C knives in my collection, I would say more are damaged and scratched from BAD sharpening technique than from use. I wonder how much the blade grind affects scratching. The earlier blades being semi hollow ground with a thicker edge tend to push material away from the blade side while the later 420HC knives are full hollow ground which allows the material being cut to wedge and scrape up the side of the knife. I suspect that the earlier steels are more scratch resistant but can only offer one personal example. I have a 1987 422 (425M) which has done more pocket duty than any knife I own and the blade is remarkedly scratch free.
 
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Roger, it could be the grind difference. Never thought of that. I was thinking more along the line with David - the higher chromium content of 440C, but wasn't sure if the difference was significant enough.

This chart shows the two steels side by side.

Knife-steel-chart-3.jpg


440C
Carbon 1.00%
Manganese .50%
Chromium 17.50%
Silicon .35%
Molybdenum .50%

420HC
Carbon .45%
Manganese .80%
Chromium 13.00%
Silicon ..80%
Nickel <.50%


At one time, I owned a Fallkniven F1 (VG10 core laminated with 420J2) and that thing scratched if you just look at it funny. This experience made me wonder about 420HC.
 
TAH said:
..... At one time, I owned a Fallkniven F1 (VG10 core laminated with 420J2) and that thing scratched if you just look at it funny. This experience made me wonder about 420HC......
Click to expand...

Information I have seen puts 420J2 about 2 points lower Rockwell than 420HC because of a slightly lower carbon content so it figures that it would scratch more easily.
 
Just in sharpening the two different steels its apparent that 440 is much harder than 420. This being the case I find it obvious that the 420 knives would scratch easier than a 440 knife. In addition, a knife that appears to be scratched, or well used is much more appealing than one that shows no sign of wear. I even hate using knives that have a high polished blade. For that very reason, I force a patina on my high carbon working knives...
 
I don't give much legitimate standing to charts. As the author often lacks real world experience. I also doubt wood could scratch hardened steel. It's being scratched by some other material. DM
 
Yes but it is still similar work.

I know the ease of finishing of steel is highly dependent on various small % components: For instance Aus-8 has an extra component added by the Japanese that makes it easier to finish than the similar 440B/C: They did this quite deliberately for that specific purpose... When erasing scratches with sandpaper, going parallel to the grain, the ease of re-finishing of Aus-8 compared to 440B is quite noticeable, yet the component involved is in very small amounts.

Scratching behaviour is a very peculiar aspect that is quite affected by steel alloys, and the differences appear to be significant from only small changes.

Gaston
 
Yes, 425M and 440A are close to AUS8. 420HC will scratch a bit easier than 440C because the chromium content is higher in the 440C and makes is harder and more stain resistant, too. 420j is worse still (relatively). The 420 series are often used to clad (laminate) harder, but more brittle steels so the blades will still give a bit but still have the performance of the super steel. An example of this is ZDP-189 clad with 420, or Super Blue (non stainless) clad with 420.
 
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