Blade material is an incredibly important aspect of any knife. And you can find various kinds of steel used for knife blades. Some are relatively soft steels, which may dull fairly quickly but be easily re-sharpened. Other steels may be very hard, and so could be ground to an incredibly sharp edge, but they may be prone to chipping or break easily if used inappropriately (for prying, for example).
On earth of knife steel, there’s always a bargain between strength (ductility, or the capacity to bend rather than snap), hardness (ability to withstand impact without deforming), edge-retention, and corrosion-resistance. Typically, as you characteristic increases, another will decrease.
Like, a few of the strongest, toughest knives are just moderately sharp (comparatively speaking), and are extremely prone to rust. But with proper maintenance, they can provide a time of hard use that would damage or destroy a blade made from a different type of steel.
The choice of blade steel will impact the correct usage of the knife, its ease or difficulty of manufacture, and needless to say, its price. Let’s have a short look at a few of the more popular choices of blade steel available.
A Brief Primer on Blade Steel
All steel consists of iron, with some carbon put into it. Various grades and kinds of steels are manufactured with the addition of other “alloying” elements to the mixture. “Stainless” steel, by definition, contains at the least 13% chromium. “Non-Stainless” steels will also be referred to as carbon steels or alloy steels.
Despite its name and late-night TV reputation, stainless is not stainless. Like all steel, it too will rust. The high chromium level in stainless helps to decrease corrosion, but cannot entirely prevent it. Only proper maintenance and handling will keep your knife completely rust free. (And basically, that simply means keeping it clean and dry, lightly oiling it from time to time, and not storing it in a sheath. That simple. Ok last one: no dishwashers. Ever.)
Speaking very generally, you can find three grades of steel used for knife blades: Good, Better and Best. Each type of steel has unique properties which make it more suitable to specific designs and applications. And needless to say, the choice of steel will impact the knife’s price.
Good Blade Steel
Knives utilizing “Good” steel blades should be considered entry-level, and are generally made from rust-resistant (not rust-free — see above) stainless steel. Typically manufactured in Asia, these knives provide a fairly good economic value. These blades are generally’softer’and therefore require more frequent sharpening to keep the edge performing well. But, simply because they are in fact’softer,’ re-sharpening is rather easy. Some of the more popular stainless blade materials in this class are 420, 440A and 7Cr13MoV.
420 stainless includes a little less carbon than 440A. Many knife makers use 420 because it’s inexpensive and it resists corrosion fairly well. 420 steel sharpens easily and is within both knives and tools.
The relative low-cost and high corrosion resistance of 440A stainless causes it to be ideal for kitchen-grade cutlery. While exhibiting similar characteristics to the better-grade AUS 6 steel, it’s even less expensive to produce. 440A contains more carbon than 420, and is therefore a’harder’steel. This permits better edge retention than a blade made from 420, but is more difficult to re-sharpen.
7Cr13MoV is an excellent blade steel, that’s the alloying elements molybdenum (Mo) and vanadium (V) put into the matrix. Molybdenum adds strength, hardness and toughness to the steel, while also improving its machinability. Vanadium adds strength, wear-resistance and toughness. Vanadium also provides corrosion resistance, which will be noticed in the oxide coating on the blade.
Better Blade Steel
Better grade stainless blades contain a higher chromium (Cr) content than their entry-level counterparts. Since the quantity of chromium is increased in the manufacturing process, these blades are far more expensive. Chromium provides a greater edge holding capability, which means that the blade will need less frequent sharpening. These better grade knives sharpen reasonably easily, but it’s crucial that you employ proper sharpening techniques. The mix of great value and performance make these blades great for everyday use. Examples of these kind of steel are AUS 6, AUS 8, 440C and 8Cr13MoV.
Both AUS 6 and AUS 8 are high-grade chromium Japanese steels, which supply a great balance of toughness, strength, edge retention and corrosion resistance, all at an average cost. These blade steels will measure a hardness of 56-58 on the Rockwell hardness scale (HRc). The carbon content of AUS 8 is close to 0.75%, rendering it very suitable as an edge steel. AUS 6 and AUS 8 are extremely popular with many knife manufacturers as they are both cost-effective and good-performing steels.
440C is a reasonably high-grade cutlery steel, just like the AUS series. However, 440C contains more carbon, which escalates the steel’s hardness. Its toughness and relative low-cost make 440C stainless appealing to many knife manufacturers because of their mid-range knife series.
The Chinese stainless 8Cr13MoV includes a high performance-to-cost ratio. It’s often in comparison to AUS 8. 8Cr13MoV is tempered to a hardness array of 56-58 on the Rockwell scale. This relatively high hardness could be caused by the steel’s higher molybdenum and vanadium content.