I am going to make my best attempt at presenting the facts of this debate to you in a non biased fashion. Perhaps at times you may find my advice or opinions painting carbon steel in a more colorful fashion. I do this to level the playing field, as carbon blades get little to no recognition these days, and I feel it is my civic duty to dispel any myths, and make you informed as a buyer, so that you may make an educated decision based upon your needs and wants, not by what what mainstream marketing claims you need.
“What’s the best metal for a knife”? Many heated debates have taken place in the knife making community when that question gets proposed. It’s like asking a group of old ladies the best way to make an apple pie. Each recipe is going to be unique, and when finished, they’re all gonna look and taste different, but they’re still apple pies. Similarly, it is the same thing with blade steel. There are many different metal types that can make a knife blade, and each will get the job done to some extent. But by knowing a number of factors like the knife’s intended purpose, who will be using it, and the environment of which it will be used may help us deduce which steel may fit the job best. As a consumer you need not only be concerned about these things, but also the mission of the manufacturer, and the person selling it. Are they looking out for your best interest, or is their ultimate goal to maximize profits?
This article will not be a case study on metals. Experts have written entire books on the subject, moreover it will cover the basics of which I feel comfortable that will hopefully get you going in the right direction, so that in the future you may make an educated decision for your next knife purchase.
Also, before we get started, let me state that Metallurgical improvements during the last century have advanced so much that the differences between these metals are now somewhat obscure to the average user. Makers and buyers sometimes get so tied up in the “who’s metal is best” argument they forget to consider things like blade geometry, grinding angles, overall design and most importantly the heat treatment. Now, the average knife buyer is usually okay with an average knife. He or she will walk into Wal-Mart or Gander Mountain, pick out a knife (usually it will say stainless and made in China, if it doesn’t say where it’s made be rest assured it is not made in the US.), and it will suit their needs just fine. But, when we remove the average user from the equation, we’re left with knife buyers that demand the best knife for their particular job – a specific group of consumers that are searching past the $50 sporting goods section knife. These niche groups may consist of chefs, hunters, fisherman, butchers, utility, tactical, collectors, first responders and so on. Each field requiring something a bit different from the next, and though knife makers have been searching for it for centuries, there is no “holy grail” of knife steel that will meet every demand it may be required to do.
Knife metals are typically broken down into two categories; carbon and stainless (there’s also some semi stainless depending on chromium levels, but we’re keeping it simple for the sake of this debate). Each of these categories contain a variety of choices – of which, most will make great knives, if functionally designed, and again, heat treated properly.
Carbon steel– an alloy of iron and carbon, tough and can be very sharp. It holds its edge well, and remains easy to sharpen, but is vulnerable to rust and stains.
Stainless steel- an alloy of iron, chromium, sometimes nickel, and molybdenum, with only a small amount of carbon. Good hardenability, good wear resistance on the higher end steels, usually more difficult to sharpen than carbon steel, but is highly resistant to corrosion. Less tough than carbon steels on average.
Hardness- is a measure of a steel’s resistance to deformation. Hardness in knife steels is most commonly measured using the Rockwell C test. Hardened knife steels are generally about 58/62 HRC (hardness Rockwell C), depending on the grade. Most are typically about 58/60 HRC, although some are occasionally used up to about 62 HRC. Knife edges which plastically deform in service possess insufficient hardness. Permanent bending of the blade or permanent deflection of the cutting edge indicates insufficient hardness. Because a steel’s resistance to permanent deflection is directly related to the hardness, not the grade, corrective actions for deformation may include increasing hardness, or decreasing operating loads by increasing blade thickness. Changing grades will not help a deformation problem, unless the new grade is capable of higher hardness. (def. courtesy of Crucible Industries website)
Toughness- as considered for high hardness knife steels, is the relative resistance of a material to breakage, chipping, or cracking under impact or stress. Toughness may be thought of as the opposite of brittleness. Toughness testing is not as standardized as hardness testing. It may be difficult to correlate the results of different test methods. Common toughness tests include various impact tests and bend fracture tests. In service, wear failures are usually preferable to toughness failures (breakage). Breakage failures can be unpredictable, catostrophic, and even a safety concern. Conversely, wear failures are usually gradual, and can be anticipated and planned for. Toughness failures may be the result of inadequate material toughness, or a number of other factors, including heat treatment, fabrication (grinding abuse), or a multitude of usage issues. Toughness data is useful to predict which steels may be
more or less prone to chipping or breakage than other steels, but toughness data cannot alone predict the performance life of a knife.(def. courtesy of Crucible Industries website)
Wear resistance- is the ability of material to resist being abraded or eroded by contact with work material, or outside influences (dirt, grit, bone, etc.) Wear resistance is provided by both the hardness level and the chemistry of the knife blade. Wear tests are quite specific to the circumstances creating the wear and the application of the knife. Most wear tests involve creating a moving contact between the surface of a sample and some destructive medium. There are 2 basic types of wear damage in knives, abrasive and adhesive. Wear involving erosion or rounding of edges is called abrasive wear. Abrasive wear does not require high pressures. Abrasive wear testing may involve sand, sandpaper, or various slurries or powders. Wear from intimate contact between two relatively smooth surfaces, such as steel on steel, carbide on steel, etc., is called adhesive wear. Adhesive wear may involve actual tearing of the material at points of high pressure contact due to friction.(def. courtesy of Crucible Industries website)
Corrosion Resistance- is a measure of a knife steel’s resistance to attack in high humidity, damp, or salt environments. This resistance is established by the addition of chromium to the composition. Developing corrosion resistance in a heat treatable, wear resistant steel is a challenge that has been met with numerous specialty CPM alloys. Relative resistance is often measured in salt spray and water spray environments.(def. courtesy of Crucible Industries website)
Edge Retention- Just like it sounds. The ability to hold a sharpened edge under use.
Sharpenability- The ease of ability to sharpen a knife blade. Typically finer grained steels will take a better edge, and do it faster, than coarse grained steels. Carbon steel is more often finer grained than it’s toothier stainless counterparts. Vanadium is added to some stainless to produce a finer grain.
Questions you need to ask yourself
- What do I need this knife for? Hunting, utility, camp work?
- Am I willing to put forth a minimal amount of effort to ensure it is maintained? Dry it after use and store in a relatively dry place.
- Is a razor edge and ease of sharpening paramount, or is corrosion/stain resistance, and low maintenance more important?
- Am I going to often be exposing it to excessive humidity and/or salt water? Coastal hunter /fishers
- Do I need it for finesse work like dressing game, rigorous work like chopping brush for fire and shelter, or utility type work cutting through rope and cardboard ?
If your answers narrowed you down to an avid hunter that wants a very sharp edge and doesn’t mind a little maintenance, you may want to opt for a high carbon steel such as 01, A2, D2, or 1095. If you work outdoors on a daily basis and want a low maintenance knife for everyday tasks, a good stainless blade may be the right option for you.
Still need a little more clarification? Here is a quick look between two steels I commonly use describing some basic characteristics and properties of each.
01 carbon tool steel- Very popular with knife makers, takes a razor edge and holds it extremely well, easily sharpened, popular for use in forged damascus. Popular with hunters, chefs, and anyone whose primary concern is to have a very sharp knife that is easily re-sharpened.
This steel has little to no corrosion resistance, so some maintenance may be required, usually nothing more than storing in a relatively dry place, and a light wipe down with an oiled rag. Don’t let this scare you away, many many knives have been made from this type of steel and are still very popular today. Go visit your local sushi chef and you will most likely find a carbon steel knife near is work station. Why, because it works the best for him! Some also consider the patina on an aged carbon blade a thing of beauty.
154CM Stainless- Also highly used today for making knives, obviously better corrosion resistance than 01, little to no maintenance required to maintain. This steel is harder than 01, but not tougher. A knife made of 154CM will have a higher chromium content which increases wear resistance, important for high abrasion tasks such as cutting repetitively through cardboard or carpet, but it lacks the toughness of carbon steel. catastrophic failure or breakage becomes likely under hard abuse. A blade made of 154CM will also take more work to re-acquire a razor edge. Best suited for work in wet and corrosive environments.
On a more personal note I have somewhat of a soft spot for carbon steel knives. Their durability has proven fit throughout the annals of time, exhibiting their worthiness in the form of a beautiful Japanese Katana, to the fields of combat, and upon the land settled and hunted by our pioneers. As these knives age, their beauty and place in time becomes defined by their appearance. Stainless knives for the most part will always remain bright and shiny. A 75 year old carbon steel Bowie on the other hand, may have acquired that sought after light grey appearance only acquired through time and years of use, and it will take whoever is holding it back in history to another time and place. Someday I will hand down certain knives to my grandchildren, and like a cherished timepiece, these knives will tell a story.
Setting all that time-honored gobbly gook aside I understand that carbon blades are not for everyone. My everyday carry is made of 154CM, and I use the heck out of it. I also admit there are many applications in which stainless knives will outperform their carbon counterpart, each steel and design has its own purpose. For these reasons I offer most of my designs available in stainless and carbon steel. However, most often than not, blade design will dictate the steel used. If you are unsure what you want, please feel free to call me at anytime and we can discuss your options.
I don’t profess to be an expert in this field. What I do know is the result of hours upon hours of research performed out of necessity for the buyer, so that I may put “the best tool for the job” in his or her hands, as their life may depend on it.
Property of Cardinal Knife Co. – Chris Wiehle