What is the Best Budget Knife Steel?

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Criteria

1) To be a budget steel it must be produced with conventional ingot production. This excludes all powder metallurgy steels, of course, including Crucible CPM, Carpenter Micro-Melt, Uddeholm Superclean, and Bohler Microclean steels. I am also excluding LC200N/Cronidur 30/Z-Finit which is produced with “Pressurized Electroslag remelting” which adds cost to production. This does not exclude steels with a small nitrogen addition like 14C28N, Nitro-V, BD1N, etc. as those are produced with conventional methods they just modify processing to increase nitrogen.

2) I am considering best budget steel in terms of knives with commercial availability as well as steels available to custom knifemakers.  What is best for a custom knifemaker may be somewhat different than what is best in production knives. We will see if this affects our choices and how.

3) I will evaluate stainless and non-stainless steels somewhat separately but preferably the optimum steel would be stainless in addition to having good edge retention, toughness, etc.

4) There are bonus points for a steel that is “fine blankable” as it is less expensive for knife manufacturers to blank out the knife shapes rather than waterjet or other methods.

5) There are also bonus points if the steel can be sharpened with cheap abrasives. As budget-minded buyers probably also look for budget sharpening stones.

6) And there are bonus points if the steel is easy to grind and polish for the knife manufacturer or custom maker. This reduces costs of production making it better for budget knives.

7) I am not considering defunct or extremely rare steels like BG42, 440XH (non-PM XHP), RN15X, or other steels I know about but you haven’t heard of.

Another Caveat

Steel choice does not predict knife performance. The best steel with the ultimate heat treatment will still cut poorly with thick edge geometry. And an ultimate steel with ultimate edge geometry and ultimate heat treatment will not fix an uncomfortable handle.

Steels to Consider

Here is a big table of steels so that you can see the compositions of many of the steels that will be discussed in this article. This chart has both too many and too few steels in it as I’m sure other steels will be brought up but I also have several steels listed that I will not be seriously considering. Some of these steels are available as either a PM or ingot version and I am of course only considering the less expensive ingot version. So CruWear is conventional CruWear not CPM CruWear.

Properties to Consider

Toughness, slicing edge retention, and corrosion resistance are the primary properties we will be comparing. We have done some experimental work on these properties, which are summarized in the charts below. First is toughness, using our subsize unnotched specimens described here.

Edge retention comes from CATRA experiments which were explained in this article. I have also developed equations for predicting edge retention based on microstructure as described in this article. This will allow estimates for steels which haven’t been tested.

I have tested corrosion resistance and developed methods for predicting corrosion resistance, you can read about all of that here.

And here are the predictions of corrosion resistance for a greater range of steels:

Cost of Heat Treating

Cost of heat treating is a bit difficult to write about because every situation is different. For custom knifemakers they are either heat treating in a small furnace in their shop or sending out to an outside heat treater. Outside heat treating services for custom knifemakers sometimes also use small furnaces but there are many services that have large vacuum furnaces as well. Large knife manufacturers using high alloy steels typically also use large vacuum furnaces, either in-house or through outside heat treatment companies. However, some knife manufacturers use other methods like “belt furnaces” where the steel travels on a conveyor belt through a hot furnace and comes out the other side to either cool in air or to be dropped in oil or water. The belt furnace method allows faster cooling rates for low alloy carbon steels that need oil quenches, and can even provide benefits to high alloy steels for achieving higher hardness. For large vacuum furnaces, the cooling rates can be somewhat slow and these types of heat treatments benefit from very high “hardenability” meaning that the steel can be cooled slowly and still achieve full hardness. High alloy steels with very high hardenability have a combination of high chromium (4% or more) plus molybdenum (at least 1%, more is typically better). Steels like 14C28N or AEB-L do not have a molybdenum addition and are therefore sometimes difficult to achieve high hardness levels with large vacuum furnaces.

For forging bladesmiths steels that are “easy to heat treat” include those that do not require extremely fast quenches allowing cheaper oils like canola, and can be fully hardened over a range of temperatures, including temperatures close to where the steel becomes nonmagnetic. You can read about the magnetic transitions in this article. Using a magnet with a forge means the steels can be heat treated without a controlled furnace. This is not a particularly great way to heat treat but many beginner bladesmiths heat treat in this way. Steels like 8670 or 1080 are relatively easy to heat treat even without controlled furnaces.

Simple Carbon and Low Alloy Steels

Low alloy steels in production knives tend to be 10XX (1055, 1095, etc) and simple variants like 1095CV.  These steels are extremely cheap for the knife manufacturer and easy to sharpen for consumers. The edge retention from wear resistance is low because they have a small amount of carbide, and those carbides are the relatively soft iron carbide type (cementite). These steels require a fast quenching rate and therefore equipment specifically targeted at these steels is required. However, if they have the equipment or design their manufacturing process around it they can benefit from very low steel costs and grinding/polishing costs.

Some knife manufacturers will use something like O1 or 52100. These steels offer a bit more edge retention than the simple carbon series and can be quenched a bit slower. However, for a large knife manufacturer if it requires an oil quench there isn’t much difference between steels in terms of what equipment is required.

Of course, regardless of the low alloy steel chosen the corrosion resistance is basically non-existent. Worrying about whether or not a nickel addition to a steel like 15N20 or a chromium addition to 52100 will improve corrosion resistance would still put the steels well below even high alloy non-stainless steels like A2.

With forging bladesmiths they have a wider range of available steels but most of them have relatively low edge retention. The highest edge retention steels in this category are Blue Super and 1.2562. Blue Super is expensive to obtain outside of Japan and 1.2562 is difficult and expensive to obtain anywhere. There are some relatively inexpensive knives produced in Japan, particularly kitchen knives, that are made in Blue Super, however. These steels have somewhat higher edge retention than other low alloy steels but toughness is not particularly high. I discussed in the CATRA edge retention article that iron carbide didn’t seem to contribute to edge retention in cutting the silica paper. If we assume that this is a quirk of the test and that the cementite would show up in cutting other media, the edge retention of these steels would be more like 420 mm, rather than the 350 mm that was measured. Also in a recent article there were new tests by knifemaker Marco Guldimann where the toughness of 1.2562 was improved. However, even if we give the steels the benefit of the doubt and raise their toughness and edge retention scores based on those factors, it doesn’t push the steels to higher levels than the best of high alloy stainless and non-stainless steels in terms of toughness-edge retention balance, and the lack of corrosion resistance in these steels means I cannot name them the best budget steels.

Toughness-Edge Retention Balance

You can have higher edge retention or you can have higher toughness but it is difficult to get both at the same time. So we want to identify steels that have the highest combination of both. There are several high toughness steels in the budget category because it is possible to design steels with low carbide content which improves toughness. With low carbide contents the carbides can be kept small even without powder metallurgy. However, these steels generally have low edge retention. But when conventional steels have significant amounts of carbide for higher edge retention those carbides tend to become pretty large leading to poor toughness. So we end up with steels with relatively high edge retention but the toughness is also pretty low. It is challenging to design steels which strike a balance in the middle somewhere. Powder metallurgy has allowed the development of more steels which achieve high edge retention with decent toughness or steels that strike a more middle-ground in terms of these properties.

The 1.2562 point used the modified values for toughness and edge retention I discussed before. It looks decent, being better than Niolox or 440C though not spectacular. 52100 also has a decent balance of properties for forging bladesmiths. You can see that 8670 has very low edge retention but also manages stellar toughness along with it. A steel like 5160 would be similar. Either of those choices are good for forging bladesmiths that need excellent toughness. 14C28N manages to have very high toughness along with medium edge retention. The most wear resistant steel we are looking at is CruWear which also manages okay toughness at around 9 ft-lbs.

High Alloy Non-Stainless Steels

The ~8% Cr steels like A8Mod, Sleipner, and CruWear manage a pretty good balance of properties along with also having some corrosion resistance. I wrote about the history of these steels and their properties in this article. I haven’t tested Sleipner or similar steels but they would be expected to be somewhere in between A8 Mod and CruWear in terms of toughness and edge retention. So these are probably the best choices for non-stainless steels, in my opinion, though they aren’t particularly common in either production or custom knives.

High Speed Steels

High speed steels generally target high hardness, wear resistance, and “hot hardness” without much focus on toughness. M2 is probably the most balanced of the various conventional high speed steels, with good toughness and relatively high wear resistance. I have only tested the toughness of M2 at high hardness though perhaps in the 60-62 Rc range it could do a bit better for different applications. High speed steels are a decent place to look for very high wear resistance conventionally produced steels, as steels like M4 or T15 have been available without PM processing, though non-PM T15 is probably rare at this point. Those steels have 4-5% vanadium giving them excellent edge retention.

Stainless Steels

Steels like AEB-L or 14C28N manage to have excellent toughness while also being capable of 60+ Rc. The toughness is similar to steels with lower carbon content like 420HC but with higher potential hardness. AEB-L and 14C28N also have moderate edge retention though of course much lower than vanadium-alloyed powder metallurgy steels like S30V or M390. 14C28N is essentially AEB-L (or perhaps more accurately Sandvik 13C26), but with improved corrosion resistance. Despite the improved corrosion resistance, it is still capable of similar hardness (above 62 with cryo), and in CATRA testing it even had slightly improved edge retention. Going any higher in carbon or edge retention means a very large drop in toughness such as Niolox, VG10, or 154CM. There are other steels I didn’t test like AUS-6, AUS-8, or 8Cr13Mov, but those steels are unlikely to have a better combination of properties than 14C28N. So 14C28N has the best balance of the stainless steels in my opinion.

What is the Best?

So after reviewing many of these steels I think 14C28N is the best. It has high toughness, above average corrosion resistance, and decent edge retention. It is also “fine blankable” and easy to sharpen with any stones, which were mentioned as bonus categories at the top of the article. The steel also has high “grindability” and “polishability” which makes costs low for knife manufacturers or custom knifemakers. As mentioned in the heat treating section, the hardenability is not particularly high for a stainless so heat treating in large vacuum furnaces is somewhat more difficult but certainly not impossible. Availability of 14C28N is somewhat worse than AEB-L so AEB-L can be a replacement with somewhat lower corrosion resistance when 14C28N is not available in the right size. I think these steels are appropriate for either knife manufacturers or custom makers so I don’t think there’s much reason to differentiate in that respect. The only exception is forging bladesmiths who tend to prefer low alloy steels and to them I would recommend 52100 for its good combination of toughness, edge retention, availability, and ease in grinding and polishing. For custom knifemakers I have a separate article on how to pick steels.