So you're looking to buy a knife, but you really don't know what to buy. Don't blame you. I mean, all those confusing numbers that knife makers and manufacturers throw at you can be more than a little daunting, and what exactly do they really mean anyway? Does it really make a difference? Or is it all just another form of hype? Well no, it's not just hype; but when you get right down to it it almost takes a degree in metallurgy to make sense of them all. So how do you decide? What steel do you want. and how do you tell?
For starters, steel is an alloy made up of Iron, Carbon, and up to 10 other elements ranging from Chromium to Manganese in specified amounts; and the various numbers represent specific "recipes" if you will. Each element adds something to the steel, and knowing what each adds tells you how each steel will work when made into a blade, be it a knife, a sword, or an ax.
Carbon is probably the most important element, since without carbon steel would be nothing more than wrought or cast iron with a handful of impurities in it; and iron really doesn't make a very useful blade. There's a reason after all why bronze was still used for weapons long after iron was discovered after all. Carbon adds a toughness and hardness to the iron that makes it steel, and the higher the carbon content, the harder you can make the steel. The problem is that the harder a metal is, the more brittle it's likely to become. I mean, look at a diamond! A diamond is the hardest naturally occurring substance known to man, and it's basically pure carbon that's been subjected to unimaginable pressure for thousands of years. Yet even though a diamond can cut through anything I know, one sharp blow from a small hammer and all you've got left is dust (which isn't all that useful now, is it). So for all practical purposes, you really can't get too high above 1% carbon or your knife is going to break the first time you stress it too much. Oh yeah, if carbon is all it really has going for it it's also going to rust the first time you look at it cross-eyed. On the other hand, it's hard to beat a high carbon steel for toughness and taking an edge. This is why many "survival" knives and butcher knives are made of high carbon steel (as well as why many are coated). Most of the time these knives will be made of what in the U.S. are referred to as 10 series metals such as 1045, 1080, and 1095. The 10 part of the number tells you it's high carbon while the second set tells you approximately what percentage of carbon is used, with 1095 being close to 1% carbon.
Chromium is the second most often used element in steel making, and it's what generally makes a steel "stainless". Don't get me wrong now. Even the most "stainless" of steels are still going to rust and discolor over time; but chromium will stretch that time out to years as opposed to weeks, or even days. It can also help with the hardness, making heat treating the blade more effective; and it can help raise the tensile strength of the steel. Another element that can also help in these endeavor is Magnesium, as well as Molybdenum. Then there are elements added to increase strength, wear resistance, and workability. Each one must be used in precise amounts, and those amounts determine the number, or "name" assigned to each particular steel, whether it's 440C, AUS-8, S30V, or 8Cr13MoV. But that still leaves the question of which steel should you be looking for in your new knife, and how much does it really matter.
Well here's where I'm probably going to piss some knife lover's off. In the end, at least in my opinion, the knife maker means more than what steel they use. Why? Well first off, as you've already noticed, it really does take someone with a degree in metallurgy to keep all this straight; and I don't know about you, but if I had a degree in metallurgy I sure wouldn't be working in the field I'm currently in! However the good knife makers all have metallurgists on their payrolls making sure that their knives are made of the right stuff. After all, Spyderco doesn't want a reputation 40 years in the making to go down the drain because of a bad decision on what type of steel to use. Secondly, each type of steel has it's own best uses. I know that if you go on many knife forums you'll hear people loudly decrying one type or steel or another, such as 440C; and yet 440C was the steel of choice for many years, and it's still used for many high end kitchen knives even to this day. The problem isn't 440C, it's low cost knife makers who routinely cut corners (especially in heat treating their knives) that gave 440C such a bad reputation. It also didn't help that since 440C could be heat treated to such a high hardness scale it could be used for knives that were advertised as "never needs sharpening", which basically means "can't be sharpened". If the company making your new knife really cares about it's reputation and the quality of it's knives, then it will make sure the knife is heat treated properly AND that it can be cared for (unlike the old Ginsu knives of yesteryear). Beyond that though, I will admit that I love my Schrade Frontier with it's 1095 high carbon, powder coated blade as well as my Kershaw made with 8CR13MoV. I also can't imagine cooking without my Gunter Wilhelm filet knife with it's X50CrMoV15 German made steel or my 30 year old Chicago Cutlery chef's knife with it's 440C steel blade. But there you have it. 4 very different knives made of 4 very different steels, and I wouldn't trade one of them.
But it's getting late, and as usual, I've rambled on almost long enough to have written a book instead of a blog. So until next time we meet here in my little corner of cyberspce, I wish you clear skies and smooth sailing. And as always, remember. If it's worth doing, it's worth doing with attitude!