This is mostly aimed at the folks who are just finding their way into the world of knives and have no idea where to start. Everyone else can disregard.
Ive had an interest in knives for close to 30 years. Unfortunately having an interest doesnt necessarily translate into having any usable knowledge, and I ended up spending good money on garbage knives, mostly because I just didnt know any better. When I first started buying knives my main criteria were what looked cool, and what I could afford. That meant I usually ended up with cheaper import knives that dulled quickly and fell apart after any hard use. I also ended up with knives made from steel that was a poor fit for my needs (for example: I had a slipjoint in 1095 which is a fine steel if maintained well, but poorly suited to bouncing around in my pocket in 90% humidity day after day with no maintenance other than sharpening. Obviously this knife rusted and pitted in short order, not because it was a bad knife, but because it was a bad fit for my needs at the time).
Over the past few years Ive become more knowledgeable on the topic and so, in an effort to help those who are just starting to explore the world of knives I thought Id post what I wish Id known about steels and knives back when I first started exploring the field. Please note that this is my opinion, and others will have different experiences and opinions. Because of that, I always welcome any additions/corrections/comments/other experiences that people have. So if you disagree with whats written here, by all means please put in your two-cents. Thats the whole point of the thread anywayto help people get an idea about what to look for, what to consider, and what they can expect from different steels.
So here goes.
A) First, contrary to what many new knife enthusiasts think, there is no overall best steel. So forget trying to get "the best knife" out there. It doesn't exist. Different steels are designed for different applications, and there are literally hundreds of steels out there. Individual users have different needs, different budgets, and subject their blade to different stressors. Therefore the optimal steel will vary from one user to the next. Just something to keep in mind. I, for instance, currently own knives in a variety of steels including 440C, VG10, S30V, and S35VN, but my most common EDC for the past 8 years has been in 420HC because that is best suited to my purposes at this time, even though most would consider it inferior to several of my other knives.
B) Second, blade steel is only one part of the equation when it comes to choosing the right knife. Other considerations of equal importance might include: intended application, edge geometry, heat treatment, and ergonomics for that user.
Example 1, intended application: D2 might make an excellent fixed-blade for the backpacker in a dry locale due to its strength, carbide type and distribution, and edge-holding ability, but would make a terrible choice for a dive knife because of its lower chromium content and tendency to corrode when exposed to salt-water and marine air.
Example 2, edge geometry: most users would agree that CPM-154 is generally superior to 440A. But if you sharpen both knives at 20+ degrees per side, youre not going to see much difference in actual performance, so why would you pay the extra for the more premium steel? The higher-end steel can take a thinner edge, and you only gain the benefit of that steel if you sharpen it accordingly.
Example 3, heat treatment: the stamp on a particular blade doesnt always mean as much as you think. These days you can get cheap import knives that claim to be made with high-end steels (and maybe they are, who knows?). But if the steel has simply been shaped into a blade in its annealed state, and never properly heat-treated, then it will never perform as intended and that premium steel is useless to you. Heat treatment makes a world of difference. Unfortunately, there is no way to know what heat treatment a particular blade has received unless youre prepared to do some fairly involved testing (and even that can be inconclusive). That being the case, your best bet is to buy from a maker that has a good reputation for quality heat treatments, and avoid knives from unknown sources where the heat treatment is impossible to verify.
Example 4, ergonomics: A knife may have the perfect steel for your particular usage, be sharpened to the correct angle for your taste, and have an excellent heat treatment, but if the knife fits your hand poorly and gives you blisters then its not a good knife for you. Ergonomics is important and often overlooked! I would rather spend time using a knife in 440A that fits my hand, than using a knife in S90V that doesnt.
C) To understand what makes different steels better or worse for different applications you need to understand basic steel composition. Please note Im no metallurgist and this is a huge topic that people literally spend their lives studying, but here is a VERY brief cliff-notes version.
In general you want steel that has 1) strength (ability to take stress without deforming) to hold an edge when you cut through hard objects, 2) toughness (ability to take a strike without fracture) so the edge doesnt chip, 3) corrosion resistance (ability to be exposed to other substances without degradation), and 4) abrasion resistance (ability to withstand repeated wear without losing steel to the abrasive object). The combination of these factors is what gives you an edge that will last through your various cutting tasks.
If the difference between strength and toughness is confusing, consider this: glass is very strong, but not tough. If you put weight on glass, it doesnt bend much. But tap that weight on the glass and it will shatter. Rubber is not at all strong, but is very tough. If you put a weight on rubber, the rubber flexes and bends. But if you hit the rubber with a weight, it does not shatter or break. A knife needs to be both tough and strong in order to function well. In order to achieve strength and toughness as well as corrosion and abrasion resistance, steel makers add various elements to their steels. Familiarizing yourself with the following will help you assess different steels and the various pros/cons of each.
The following elements are used in different steels and each has its own benefits.
Iron (Fe): substrate material, necessary for all steel.
Carbon (C): primary alloying element, necessary for all steel. Improves strength. Also combines with other elements to form carbides which are critical for abrasion resistance. Carbides are essentially little inclusions in the steel that are very hard. Think of them like pebbles in a concrete freeway. Without the pebbles, the freeway wears down faster. With the pebbles the freeway surface is just slightly rough, but lasts much longer. Carbides provide abrasion resistance for the steel, and also give your edge a very slight toothiness that improves cutting performance.
Chromium, (Cr): Alloying element necessary for stainless steel. At least 13% needed to be considered stainless. While no steel is truly stainless, the higher the chromium content the more stain/corrosion resistant the steel will be. Imparts slight improvements to strength. Also forms carbides thus improving abrasion resistance. In high quantities decreases toughness (makes blade more brittle).
Molybdenum, (Mo): improves corrosion resistance, strength, and toughness, forms carbides.
Manganese (Mn): improves strength and deoxidizes steel during manufacture. Usually used in combo with Si as their effect together is more potent than either one alone.
Silicon, (Si): improves strength and deoxidizes steel during manufacture. Too much increases brittleness.
Nickel (Ni): improves toughness, may contribute to slight increase in strength.
Tungsten (W): forms strong carbides, thus improving wear resistance
Vanadium (V): forms very strong carbides, thus improving wear resistance. Also refines the grain of the steel, improving overall quality. Present in almost all premium steels.
Nitrogen, (N): Improves strength. Combines with other alloying elements to form nitrides which act similarly to carbides in improving abrasion resistance
Cobalt (Co): imparts strength, especially at high temperatures and allows the steel to be hardened to a stupid-high level.
Niobium (Nb): Improves toughness, strength, and abrasion resistance.
Ive had an interest in knives for close to 30 years. Unfortunately having an interest doesnt necessarily translate into having any usable knowledge, and I ended up spending good money on garbage knives, mostly because I just didnt know any better. When I first started buying knives my main criteria were what looked cool, and what I could afford. That meant I usually ended up with cheaper import knives that dulled quickly and fell apart after any hard use. I also ended up with knives made from steel that was a poor fit for my needs (for example: I had a slipjoint in 1095 which is a fine steel if maintained well, but poorly suited to bouncing around in my pocket in 90% humidity day after day with no maintenance other than sharpening. Obviously this knife rusted and pitted in short order, not because it was a bad knife, but because it was a bad fit for my needs at the time).
Over the past few years Ive become more knowledgeable on the topic and so, in an effort to help those who are just starting to explore the world of knives I thought Id post what I wish Id known about steels and knives back when I first started exploring the field. Please note that this is my opinion, and others will have different experiences and opinions. Because of that, I always welcome any additions/corrections/comments/other experiences that people have. So if you disagree with whats written here, by all means please put in your two-cents. Thats the whole point of the thread anywayto help people get an idea about what to look for, what to consider, and what they can expect from different steels.
So here goes.
A) First, contrary to what many new knife enthusiasts think, there is no overall best steel. So forget trying to get "the best knife" out there. It doesn't exist. Different steels are designed for different applications, and there are literally hundreds of steels out there. Individual users have different needs, different budgets, and subject their blade to different stressors. Therefore the optimal steel will vary from one user to the next. Just something to keep in mind. I, for instance, currently own knives in a variety of steels including 440C, VG10, S30V, and S35VN, but my most common EDC for the past 8 years has been in 420HC because that is best suited to my purposes at this time, even though most would consider it inferior to several of my other knives.
B) Second, blade steel is only one part of the equation when it comes to choosing the right knife. Other considerations of equal importance might include: intended application, edge geometry, heat treatment, and ergonomics for that user.
Example 1, intended application: D2 might make an excellent fixed-blade for the backpacker in a dry locale due to its strength, carbide type and distribution, and edge-holding ability, but would make a terrible choice for a dive knife because of its lower chromium content and tendency to corrode when exposed to salt-water and marine air.
Example 2, edge geometry: most users would agree that CPM-154 is generally superior to 440A. But if you sharpen both knives at 20+ degrees per side, youre not going to see much difference in actual performance, so why would you pay the extra for the more premium steel? The higher-end steel can take a thinner edge, and you only gain the benefit of that steel if you sharpen it accordingly.
Example 3, heat treatment: the stamp on a particular blade doesnt always mean as much as you think. These days you can get cheap import knives that claim to be made with high-end steels (and maybe they are, who knows?). But if the steel has simply been shaped into a blade in its annealed state, and never properly heat-treated, then it will never perform as intended and that premium steel is useless to you. Heat treatment makes a world of difference. Unfortunately, there is no way to know what heat treatment a particular blade has received unless youre prepared to do some fairly involved testing (and even that can be inconclusive). That being the case, your best bet is to buy from a maker that has a good reputation for quality heat treatments, and avoid knives from unknown sources where the heat treatment is impossible to verify.
Example 4, ergonomics: A knife may have the perfect steel for your particular usage, be sharpened to the correct angle for your taste, and have an excellent heat treatment, but if the knife fits your hand poorly and gives you blisters then its not a good knife for you. Ergonomics is important and often overlooked! I would rather spend time using a knife in 440A that fits my hand, than using a knife in S90V that doesnt.
C) To understand what makes different steels better or worse for different applications you need to understand basic steel composition. Please note Im no metallurgist and this is a huge topic that people literally spend their lives studying, but here is a VERY brief cliff-notes version.
In general you want steel that has 1) strength (ability to take stress without deforming) to hold an edge when you cut through hard objects, 2) toughness (ability to take a strike without fracture) so the edge doesnt chip, 3) corrosion resistance (ability to be exposed to other substances without degradation), and 4) abrasion resistance (ability to withstand repeated wear without losing steel to the abrasive object). The combination of these factors is what gives you an edge that will last through your various cutting tasks.
If the difference between strength and toughness is confusing, consider this: glass is very strong, but not tough. If you put weight on glass, it doesnt bend much. But tap that weight on the glass and it will shatter. Rubber is not at all strong, but is very tough. If you put a weight on rubber, the rubber flexes and bends. But if you hit the rubber with a weight, it does not shatter or break. A knife needs to be both tough and strong in order to function well. In order to achieve strength and toughness as well as corrosion and abrasion resistance, steel makers add various elements to their steels. Familiarizing yourself with the following will help you assess different steels and the various pros/cons of each.
The following elements are used in different steels and each has its own benefits.
Iron (Fe): substrate material, necessary for all steel.
Carbon (C): primary alloying element, necessary for all steel. Improves strength. Also combines with other elements to form carbides which are critical for abrasion resistance. Carbides are essentially little inclusions in the steel that are very hard. Think of them like pebbles in a concrete freeway. Without the pebbles, the freeway wears down faster. With the pebbles the freeway surface is just slightly rough, but lasts much longer. Carbides provide abrasion resistance for the steel, and also give your edge a very slight toothiness that improves cutting performance.
Chromium, (Cr): Alloying element necessary for stainless steel. At least 13% needed to be considered stainless. While no steel is truly stainless, the higher the chromium content the more stain/corrosion resistant the steel will be. Imparts slight improvements to strength. Also forms carbides thus improving abrasion resistance. In high quantities decreases toughness (makes blade more brittle).
Molybdenum, (Mo): improves corrosion resistance, strength, and toughness, forms carbides.
Manganese (Mn): improves strength and deoxidizes steel during manufacture. Usually used in combo with Si as their effect together is more potent than either one alone.
Silicon, (Si): improves strength and deoxidizes steel during manufacture. Too much increases brittleness.
Nickel (Ni): improves toughness, may contribute to slight increase in strength.
Tungsten (W): forms strong carbides, thus improving wear resistance
Vanadium (V): forms very strong carbides, thus improving wear resistance. Also refines the grain of the steel, improving overall quality. Present in almost all premium steels.
Nitrogen, (N): Improves strength. Combines with other alloying elements to form nitrides which act similarly to carbides in improving abrasion resistance
Cobalt (Co): imparts strength, especially at high temperatures and allows the steel to be hardened to a stupid-high level.
Niobium (Nb): Improves toughness, strength, and abrasion resistance.
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overall really good read though