Thoughts on 440-C these days?

[M&J]

What are your thoughts on 440-C these days?

I've gone through most the ATS-34 stock and have strays of 01, D2 but a good amount of 440C on hand.

[epicfail48]

Buying or using? If buying, AEB-L is loads cheaper and seems to be more friendly to work with. Using? AEB-L is loads easier to sharpen, to me, and seems to take a better edge. I dont think that 440c is bad, after all if it was it wouldnt be as common as it is, but i do like AEB-L a lot more when it comes to stainless

[dtec1]

I use it sometimes from what I ahave been told it got a bad rep because of the other 440 steels....but at the same time I deffinitly wouldn't call it a great steel its good not great steels like the cpm steels especially cpm s35vn are much better.....but if you have it use it!

[WBE]

I would call one of the great steels, with a cryo treatment. If a steel is easier to sharpen than another, that means it has less abrasion resistance, and you will wear the edge faster.

[M&J]

Bought up some of a retiring maker's steel many years back. He had about 250' and roughly down to about 150' at this point. I've liked working this but haven't used it in years now. When I send steel in if they offer cryo treatment I option that. Been pleased in that regard.

Working up a knife and getting them cold shouldered because this isn't the trendy steel has me wondering. Maybe time to do a dagger or similar...

[dtec1]

440c is deffinitly better with cryo but then so is most stainless steels. I have a liquid nitrogen container so I cryo all my blades....from what I am told most stainless NEED it especially the higher end steels but even with the few stainless that can be done without liquid nitrogen they always benefit from it wich Is why I cryo everything

[samuraistuart]

The point of the cryo LN2 (and even sub zero dry ice slurry) is to minimize retained austenite in a steel after it is quenched. What does that mean to us as makers? Put simply, a slight boost in hardness. Usually 1-3 points HRC. When making knives, it is always advisable to get as much martensite as possible during the quench, and then temper down to desired hardness.

If one were to quench 440C without using the sub zero or LN2 quench continuation, then the max HRC you're likely to get is around 59HRC or so (if memory serves me right). That's a good hardness, no doubt, and quite serviceable. However, there is going to be some amount of retained austenite in that blade, and RA is a soft generally undesirable structure in blade steel. If one were to add the sub zero or cryo post quench (before any tempers), then the RA will be minimized, and the final HRC will be several points higher. 62 or 63. You could leave it at that hardness, or temper down as desired.

I had some kitchen knives from Boker (Prestidges or some weird name like that). They had 440c, and I was impressed with their performance. MUCH MUCH better than the other "generic" stainless steels out there like 440a or X50 whatever from China. 440c is no slouch.

(Some steels that are VERY highly alloyed will not have decent RA conversion even with extended soaks in LN2!!!! They need the secondary hardening tempers (~1000°f) to eliminate the RA, but that causes different issues for a knife blade. Think steels like T15. I sure wouldn't want to be the guy putting a hand rubbed finish on steels like that! Count me out. CPM M4 is bad enough!)

[dtec1]

yeh the liquid nitrogen soak in a way you can think of it as a extension of the actual quench converting more austenite....I will say there is a difference between CRYO (liquid nitrogen) wich is a little more than minus 300 deg F a dry ice slurry is only about half that of liquid nitrogen some steels that is ok for but some steels the dry ice will do nothing....I have a liquid nitrogen tank so I never use dry ice.


as far as those high tempers I never use that like you said it brings up other issues I agree with that BUT what I don't agree with is that liquid nitrogen wont do anything for high alloy steels I have found quite the opposite that the high alloyed stainless really needs the cryo bath early on I did a couple cutting test and found that the difference was so much I never actually tested it again and cryoed all my blades no matter what some of the simpler steels don't need it the complex steels do need it but I look at it like it may not always be needed with all steels but it will never hurt so I do it on everything

[Andrew Garrett]

440C isn't very 'fashionable' these days. None of the 'extreme' guys will be beating down your door for a knife made from 440C because it isn't the latest or greatest wonder steel.

That said, 440C is a very good steel with well established heat treating procedures, and I use it on stainless versions of my push daggers.

[argel55]

I don't see any problem with 440C. It is a good knife steel. I thought it was a little gummy grinding but other wise held a good edge. Sharpest knives I ever made were the 440 that Jim Barbee heat treated for me. Found out years later that he was cryoing and his heat treat oven was built by NASA scientists.

[M&J]

I attempted to sell some and it doesn't draw much interest. Some of the suppliers do sell a little bit though largely no. Been pondering a dagger.

What would you use 440-C for?