Knives: High Carbon Steel vs Stainless, What’s the Difference?

RAT7There’s a lot of talk in the survival community about knives. The opinions on them vary like the weather. But one thing we can all agree on is that they should be made of either high carbon, or stainless steel (unless there is something really super cool out there that’s like, the best of both…cough)

So let’s start with high carbon. What is it and what properties make it useful for survival knives?

Cutting to the chase (couldn’t resist), “high carbon” is any steel that contains at least 0.3% carbon. Steels in this category can be more brittle, are easier to sharpen, hold a sharper edge,  but tend to rust much more easily.

Examples of high carbon steels are:

Lets pause to point out that stainless steel is any steel that contains a least 10.5% chromium by mass.

ESEE-5S-OD***NOTE: High carbon 1095 steel contains ZERO chromium, and thus it is highly corrosive, but very sharp. Again, these are typically your ESEE and Ontario RAT series knives, so keep that in mind. Make sure they have a corrosion resistant paint treatment on the blade. The edge won’t have it, so again, #0000 steel wool in your pack becomes a necessity here.

For Spyderco’s detailed list of steels and their carbon/chromium content, click here.

Again, disadvantages of high carbon steel are: it’s tendency to rust and stain easy.  Staining happens with anything acidic like tomatoes, citrus fruits, wine or vinegar. It can also sometimes be brittle.

As for stainless steel, it has one VERY distinct advantage over a high carbon blade: corrosion resistance. A stainless blade should be your first choice when working in a very humid or wet environment, or near/on the sea. End of story. Examples include:

  • 154CM (1.05% carbon + 14% chromium)
  • 20cv (1.9% carbon + 20% chromium)
  • 440 A,B,or C (0.65-1.0% carbon + 13.5-18.0% chromium)

There is however, a wild card in this equation; the high carbon stainless knife. Remember, any blade with more than 0.3% carbon is high carbon, but if it also has at least 10.5% chromium is now considered “high carbon stainless”, and thus, you get the best of both worlds. To make things simple, here are few steels that meet both requirements:

  • 9Cr18Mo (0.9-1.1% carbon + 16.0-18.0% chromium)
  • Aus-10 (0.95-1.1% carbon + 13.0-14.5% chromium)
  • 8Cr13MoV (0.8% carbon + 13.0% chromium, ex: most Schrade Knives)
  • 12C27 (0.6% carbon + 13.5% chromium, ex: Mora knives)
The Schrade SCHF37M
The Schrade SCHF37M

Remember, the more chromium it has, the more corrosion resistant, but it will also require more effort, more frequently, to keep sharp. Again, knives with a high chromium content are great for wet/humid environments, but if you were heading into a very DRY environment, say, a desert environment, you may very well want to take a blade with high carbon and NO chromium. In a very dry environment, rust may not be as much a concern compared to how sharp your knife is, and how long it stays that way.

Still with me? Okay, lets summarize:

High Carbon: anything over 0.3% carbon, harder metal. Gets very sharp, hold a good edge, better for striking ferro rods, but rusts easy. Too much carbon also makes the blade brittle. Take to dry environments.

Stainless Steel: anything over 10.5% chromium, softer metal. Doesn’t rust or stain easily, but not as easy to sharpen, and doesn’t hold the edge as well as high carbon.

High Carbon Stainless: Best of both worlds. Sharpens easily, holds a great edge, resists rust better than a straight high carbon steel like 1095, also strikes a ferro rod really well.

However, it’s important to point out that sharpness of a blade is not strictly dictated by it’s carbon/chromium content. That would make life too simple, wouldn’t it? Unfortunately, sharpness is also affected by the thickness of the blade, the primary grind type, primary grind angle, edge grind angle (all part of edge geometry), the transition of the grinds, etc, etc, etc…subjects we don’t really need to cover here. Feel free to research all those things on your own, but at least you can now read the back of the box and check the steel type, and decide for yourself if the knife you’re about to buy fulfills a need for you, depending on where you want to take it, and what you want to do with it.

That’s all for today, hope you enjoyed your crash course in knife steel.

Ne te quaesiveris extra

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One Thought to “Knives: High Carbon Steel vs Stainless, What’s the Difference?”

  1. […] In metallurgical terms the Bolo is 3Cr13 steel, technically high carbon stainless (I prefer to call it medium carbon) with an HRC of 52-55. In simple terms: it’s relatively soft with 0.3% carbon (the minimum value for “high carbon”), and 13% Chromium, making it relatively rust-resistant, but not entirely. I noticed some rusting and pitting about 6 months in, but to be honest, I never polished the blade, I only rinsed it clean, wiped it dry and put it away. Today I Never-Dull’ed it, and this was still left, so make sure you clean it well and polish it up little after putting it through its paces. Other brands who use 3Cr13 steel include SOG, and CRKT just to name a couple. (For a detailed explanation of how to pick a blade based on it’s steel type and your intended use, click here.) […]

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