Introduction

Rewind a decade and a half and ask the question, “What is the best stainless steel for knives?” An overwhelming majority would have sung the praises of 440C. Arguably the most famous folding knife in American history, the Buck 110, was made of 440C prior to 1981. On the other hand, 440C has been judged, loved, hated, belied, cursed, and praised more than almost any other metal to have found itself the recipient of the bladesmith’s hammer. Why does this particular stainless steel incur such a wide-ranging response from those who know it best? The answer is trickier than it may seem.

Chemical Composition

440C stainless steel is a Martensitic steel with a composition of:

Chemical	%
Iron	79.15
Chromium	17
Carbon	1.1
Manganese	1
Silicon	1
Molybdenum	.75

This stainless steel has a Rockwell hardness of 57-60 HRC. Lying somewhere between AUS8 and VG-10, 440C provides excellent all-around steel for many types of industrial applications such as surgical instruments, bearing races, and quality kitchen cutlery. The key to stainless steel is the balance between carbon and chromium. 

The higher the carbon, the more wear-resistant, yet lower corrosion resistance. The higher the chromium content, the higher the corrosion resistance, but the lower the wear resistance. Because of this balancing act, and the fact that it cannot be worked in the plastic temperature range using an open-air forge, small-shop bladesmiths simply do not have the equipment necessary to work this steel. 

As a result, 440C is a bit more expensive and takes a backseat to other steels. Many bladesmiths, due to an inability to work with it, call it “inferior” steel. Nothing could be further from the truth. Most metallurgists consider 440C to be the standard by which all other stainless steels are measured.

In turn, some of the most celebrated knives throughout modern history are made with this excellent material.

Properties of 440C Steel

Hardness

The 440C steel has a Rockwell hardness score ranging between 58-60HRC. This score is considered a rather decent score for a steel blade. The 440C steel is noticeably the hardest steel in the 440 series. The high amount of hardness is due to the increased content of Carbon and Chromium in the composition.

A high level of hardness enables the steel to perform really well in terms of wear and abrasion resistance and the 440C steel will not let its surface get easily destroyed.

Edge retention

The edge retention is the knife’s ability to hold its sharpness while in use. Whether it is cutting up nylon ropes, cutting fresh meat, sharpening wood, or cutting up cardboard boxes, no one wants to deal with a dull knife. The performance you can observe during cut tests is quite remarkable when you compare high-end steels to lower-end ones.

Edge retention and hardness typically go hand in hand. Due to the high hardness of the 440C steel, it also has great edge retention. Also, it is important to note that high carbon steel is usually associated with great edge retention. You can use the 440C steel knife for long periods of time without worrying about dulling the edge as compared to other knives. 

This property is especially crucial when you are venturing into the wild.

Toughness

A tough steel blade resists chipping and complete breakdown when subjected to impact, beating, twisting, and torsion. Tough blades are perfect for camping and outdoor use in the wild. Where a normal steel blade might chip or even break down, tougher steel blades are able to withstand that and much more such as batoning sessions, steel strapping, and much more!

The 440C is a hard steel, which means that it cannot be tough at the same time. But nevertheless, it has proven itself to be a decently tough steel blade. The incorporation of a high amount of content of Molybdenum plays a key role in increasing the steel’s toughness. 

This steel can resist shock and lateral forces with somewhat ease and withstand tough use.

Corrosion resistance

Are you someone who tends to venture out into the wild, salty, wet, and humid environments? Do you often use your knife for prepping meals with acidic ingredients such as tomatoes or lemon? 

Certain steels are pretty good at resisting rust and corrosion and can be left uncleaned for hours without any complications or ill effects. Carbon steel knives will easily pit and rust in wet, humid environments if not looked after properly. Usually, knives with a low corrosion resistance can be protected with a thin layer of mineral oil.

The 440C steel delivers good anti-corrosion properties. The high amount of Chromium makes it stainless steel that helps keep off corrosion, stains, and rust. High corrosion resistance is an excellent property to have as it reduces the amount of aftercare the knife requires.

Ease of sharpening

Usually, the most overlooked aspect of blade steel is its sharpenability and sharpness. Touching up or sharpening certain steels with a sharpening stone can be quite a simple, easy, and relaxing process whereas harder steels can make the process much tougher, tedious, and not so relaxing. 

Achieving the right amount of sharpness can be a life-or-death matter when you are out in the wild, as it determines your ability to cut up and cook food as well as other tasks. It is crucial to keep in mind that an easy to sharpen knife usually indicates low edge retention.

When we speak about the sharpness of the 440C steel, it is crucial to keep in mind that it is a hard steel. Since it is a hard steel, it does not rank very high in terms of sharpness. Sharpening it can take you quite some time. 

Luckily, due to new and faster methods of sharpening, you can give your 440C steel knife a great edge with lesser effort. The steel retains its sharpness for a long period of time before needing to be sharpened again, so you will not have to worry about the stress of frequent sharpening.

Stainless Steel Vs. High Carbon Steel

There are two broad categories of steel: stainless and high-carbon. Stainless steel resists rust very well but it can dull easily. High-Carbon steel keeps an edge really well but it rusts easily.  Another comparison would be that stainless would have a tendency for sharp edges to curl, bend or warp under pressure, while high-carbon steel would chip or splinter.  Most mass-produced steels are somewhere in between.

Heat treatment of 440c stainless steel

Step 1 – Full annealing

Full annealing for 440C steel is done at temperatures ranging between 850 – 900 C after which it is slowly cooled down in the furnace at about 600 C and then air-cooled down to room temperature. It can also be heated at temperatures ranging between 735 – 785 C and then slowly cooled down in the furnace until it reaches room temperature.

Step 2 – Hardening

The steel is heated once again at temperatures ranging between 1010 – 1065 C and then quenched in warm water or oil. Thicker sections of the steel should be quenched in oil to allow a faster and uniform temperature decrease, whereas thinner sections can be quenched in air.

Step 3 – Tempering

The steel is tempered at temperatures ranging between 150 – 370 C where multiple levels of hardness and mechanical properties are obtained. Tempering at temperatures between 425 – 565 C will lead to lower corrosion and impact resistance, and tempering between the temperatures 590 – 675 C will result in high impact resistance lower hardness. 

440C steel vs. other steels

440C vs. AUS 8

Properties	440C	AUS 8
Edge retention	2.5/10	2/10
Toughness	5/10	6/10
Corrosion resistance	7/10	7/10
Ease of sharpening	7/10	9/10

From the above table, it is fair to deduce that AUS 8 provides improved edge retention, toughness, ease of sharpening, and the same amount of corrosion resistance.

440C vs. 1095

Properties	440C	1095
Edge retention	2.5/10	3/10
Toughness	5/10	8/10
Corrosion resistance	7/10	3/10
Ease of sharpening	7/10	7/10

From the above table, it is fair to deduce that the 1095 steel provides improved edge retention, toughness, and ranks equally in terms of ease of sharpening. The 440C steel provides improved corrosion resistance.

440C vs. S30V

Properties	440C	S30V
Edge retention	2.5/10	5/10
Toughness	5/10	6/10
Corrosion resistance	7/10	7/10
Ease of sharpening	7/10	5/10

From the above table, it is fair to deduce that S30V steel provides improved edge retention, toughness, and ranks equal to the 440C steel in terms of corrosion resistance.

440C vs. VG10

Properties	440C	VG10
Edge retention	2.5/10	5/10
Toughness	5/10	4/10
Corrosion resistance	7/10	7/10
Ease of sharpening	7/10	6/10

From the above table, it is fair to deduce that the VG10 steel provides improved edge retention and the 440C steel provides improved toughness and ease of sharpening.

Favorites Using 440C Stainless Steel

My favorite knife in 440C stainless steel is hands down the ESEE-4 with a 4-1/2″stonewashed, flat ground .19″ blade. This full-tang, triple-riveted 9″ tactical knife features OD green Micarta handle scales and a molded plastic M.O.L.L.E. compatible sheath. The ergonomics of the ESEE-4 lends itself to be used for long periods of time with no hot spots or fatigue. 

You have the ability to chop and baton with it, yet you are also able to choke up further on the handle for carving tasks and for making feather sticks. 

The blade is a drop point and holds an edge well, typically only requiring a leather strop with jewelers rouge. It is also extremely corrosion-resistant, thanks to it being the ubiquitous 440C! One drawback that I would like to have seen on the ESEE-4 would have been a spine ground at 90 degrees to throw sparks from a Ferro rod. 

Though it’s not impossible to spark a rod, it doesn’t shower the sparks in the way that some of ESEE’s outdoor knives can do. However, to be fair, this model is classified as a tactical knife, not a bushcraft knife.

Conclusion

Given the breadth of stainless steels available on the market today, it’s no wonder 440C has been labeled “old-fashioned” and “boring.” Many small-shop bladesmiths have completely forgone stainless steels altogether, as the demand for carbon steel knife blades have enjoyed a resurgence of late. There are many reasons for this, such as ease of working the steel, less expensive materials, availability of stock, and the current market for outdoor and tactical knives. So the question we are again faced with is, why does 440C evoke such passionate discussions between bladesmiths and knife collectors?  The gulf that exists between the two camps seems wide, but at the end of the day, 440C is a very stable and reliable stainless steel that can hold its own with a great many of the new “super steel’s” of today. The choice, it seems, belongs to the one who wields the blade.