Question regarding steel types

[g_one]

I'll admit - when it comes to different types and qualities of steel, I'm completely ignorant. I understand the differences between black steel, stainless steel, galvanized steel, and that's about as far as I go.
So here's my question. I've been carrying around this knife, the gerber paraframe knife, for years. It mostly gets used for generic day-to-day stuff like cutting open boxes, packing tape, the occasional loose thread on a worn pair of jeans. Despite being a cheap knife, it isn't really beat up or rusted at all. Very minor scratches on it that are really more issues with the finish than anything. I do really like having a knife around though, and so I'm looking at purchasing something a little nicer, and I was hoping you guys could explain to me the differences in my options.
Option a is '440C' steel, runs about $100.
Option b is 'CPM S35VN' and runs about $150.
Both are available either polished or 'black titanium coated' at no additional cost.

So, school me on whether or not B is worth the extra $50 - does it hold an edge better? Resist the elements better? And is the black titanium coat purely for aesthetics?

 

[Tirod]

Black steel could be construed as carbon steel, because it's quite capable of rusting, and will take a blue. Carbon is the element that gives it the primary hardness to be used as a knife.

Stainless steel is exactly that - "stain less," not "rust proof." Stainless uses carbon, and adds a lot of chrome and some nickel to slow down rust. It can actually grow a transparent coating of oxidation which is what prevents further visible rusting.

Galvanized steel is some kind of steel, usually low carbon, which is often hot dipped in zinc or electroplated to prevent corrosion. Think, barn roof. Not much to do with knives.

440C is a good quality stainless in cutlery that can deliver good performance over it's life, and can hold an edge and resharpen relatively easily. The edge geometry and profile weren't well thought out in the early years of production which left new owners disappointed in it's performance compared to older carbon steel blades.

S35VN is one of CPM's (the maker) newer steels. If it's anything like S30V, it's extremely durable. As alloys go, the "better" grades become increasing more abrasion resistant, which keeps them sharper longer, but which makes them take longer to sharpen.

Titanium nitriding isn't a coating as much as a surface treatment of the top layer of steel, infusing it with titanium oxides which become part of the molecular structure. That improves surface hardness and makes the extremely scratch resistant - but not on the very edge where the cutting is done. That is usually ground in the final operations after nitriding. It's a nice process to have, as colors and finishes are more broadly available, and it beats the old school method of nickle or chrome plating to keep rusting at a minimum on carbon steel blades (lots of Solingen hunting knives are still sold that way.)

Is the price worth it? Depends. Outdoorsmen who plan to use their knife extensively - fixed blade - may prefer a 1095 carbon steel. They know the blade isn't going to be ignored as it's out numerous times in the day, and wiping it down or steeling it is a habit. A stainless knife for a hunter could be preferred, tho, as in the excitement of dressing out the deer and dragging it back, it could be hours before it's cleaned, and blood tends to damage polished surfaces if left on them for hours. In horribly abrasive conditions, the S35 might be a good choice - cutting web gear from a soldier in desert conditions, where powdered sand has worked into the weave of field gear than needs to be removed, and done repeatedly in the battlefield far from support.

The real issue is what kind of cutting is needed - then you match the steel to the job and get that, same as blade shape, length, type of grip material, sheath construction, lock or not. It's just another feature of the knife, and choosing one out of balance to it's intended purpose becomes an exercise in futility. Wonderful knife that can't keep an edge, or wonderful knife that requires sending it to the maker to be sharpened. Inexpensive knife that can be replaced easily, or expensive knife that brings pangs of guilt when it's discovered missing - which happens often enough.

Knives are priced a lot like watches - they are dirt cheap but still useful under $25, and pretty exotic and pricey over $450. Most knives in the $130 range are more than adequate for a daily user. Like it's said, you get what you pay for.

 

[g_one]

Thanks for the detailed answer! That helps out quite a bit.

 

[JShirley]

440C will probably be more stainless, but not hold an edge quite as long. The last two stainless steels I bought were 440C and S35VN. For smaller knives, I'd go for 440C, with that much price difference.

(edit)After more research. S35VN is supposedly more stain/rust resistant, too. Again, I still wouldn't pay 50% more for a small knife in S35VN.

John

 

[DNS]

Honestly, Bucks 420HC would be a nice step up for you and some of them are about what you paid for the Paraframe. Off the top of my head your probably looking at three points higher on the hardness scale.

I do have a couple knives in 440C and they're a pain to sharpen but are good performers.
No experience with CPM.