Introduction

That trusty old knife that you carry around is probably made of familiar steel, i.e, the 420 steel. The 420 steel is widely available in most knives. This steel provides a wide range of benefits but its weakness is that it doesn’t contribute to any one area significantly; however, this does not make it a bad blade to buy. The 420 steel serves a few purposes extremely well and is versatile where others are not. The reasons for buying a 420 steel blade may be specific or general.

Chemical Composition of 420 steel

Chemical Composition	Minimum %	Maximum %
Carbon	0.15	0.38
Manganese	0	1.00
Chromium	12.00	14.00
Sulfur	0	0.03
Phosphorous	0	0.04
Nickel	0	1.00
Silicon	0	1.00

While 420 technically has a higher carbon content than 410 and 416 sheets of steel, and it can be hardened significantly by adding heat during the production process, it is still the softest metal (to our knowledge) that is still used in blade making.  Chromium (approximately 12%) gives this steel some pretty decent corrosion resistance, which is just what it needs to be given that it will likely be used by someone who may not care for it as much (given the low price point).

420 Steel Properties

Edge Retention

An occurrence common in lower-end steels, the 420 steel has a carbon content of about 0.38%. The low carbon content signifies that it’s a rather soft material when compared to most steels, and it doesn’t seem to hold its edge too well. Usually, blades made from the 420 steel require frequent sharpening and tend to chip off easier than other blades.

But on the other hand, all 420 stainless steel blades are highly rust-resistant! This makes them great choices for diving knives since the constant contact with saltwater makes them an easier target for rusting.

Corrosion Resistance

Under toughened conditions, 420 plates of steel are highly resistant to alkalis, freshwater, foods, air, and mild acids. Usually, the steel grades with a rather smooth surface have great performance. The corrosion-resistant properties of the 420 stainless steel tend to fall under the category of annealed conditions. The corrosion-resistant properties of 420 steel are lower than that of the 430 steel alloy, comprising 17% Chromium, 410 steel, and other austenitic steels.

The 420 steel finds its use in cutlery such as table knives, carving knives, and so on. The 420 steel has comparatively decent corrosion resistance against food, but it is essential to keep in mind that constant exposure of any metal to unwashed food items can lead to pitting corrosion.

Hardness

The alloy of 420 stainless steel has a higher carbon content than that of alloy 410 of steel which is specifically designed to optimize and improve the strength and hardness characteristics of the steel. 

It has a pretty decent ductility in its annealed condition but has the capability of being hardened to a minimum hardness of 50 HRC on the Rockwell scale, which is the highest hardness of the 12& chromium grade steels.

Due to its impressive hardening abilities, alloy 420 of stainless steel is not welded, although it can be if needed. Martensitic stainless steels are usually designed for high levels of hardness, and a few times, the other properties of the steel have to be slightly compromised.

Sharpness

Since it is rather a soft steel, the 420 stainless steel becomes extremely easy and simple to sharpen, hence sharpening a 420 steel knife with even a wet stone would not take too much of your time.

Toughness

The 420 stainless steel is good in terms of toughness since the steel is more robust which leads to a lower hardness and edge retention and explains the HRC of 50 and not so impressive edge retention of the 420 steel.

Type of 420 Stainless Steel Heat Treatment

The type of heat treatment that would be required for the 420 stainless steel consist of hardening, annealing, tempering, and stress relief. The preparation requirements include preheating, precleaning, atmosphere protection, hydrogen embrittlement, and salt bath.

• Precleaning: All samples of SS420 need to be carefully cleaned for impurities such as oil, sweat, and other stains on the surface of the blade.
• Preheating: The thermal conductivity of 420 stainless steel is noted to be lower than that of carbon-rich steel. When the metal is heated rapidly, the metal can be easily deformed and cracked. Hence, preheating is often recommended. The preheating temperature range is usually between 760-790 °C (1400-1450 °F). Heavy-duty machine parts can be preheated in two separate stages: Preheat the steel at 540 °C (1000 °F) firstly, and then heat to 790 °C (1450 °F).
• Atmospheric protection: The austenitizing temperature is 1010 °C (1850 °F), and dew-point temperature is: 10-12 °C (50-54 °F) for AISI 420 wrought martensitic stainless steel.
• Salt baths: Bath salts tend to give the 420 stainless steel parts improved results.
• Hydrogen embrittlement: Hydrogen embrittlement has been noted to be a huge problem with the 420 stainless steel.

Machining capability

The 420 stainless steel grade can be quite easily machined in its annealed state, but they are usually noted to be difficult to machine since they have a hardness greater than 30HRC. One of the more readily available and machined alternatives is the free-machining 416 steel grades.

Benefits of 420 Steel

To start off with, 420 steel is great in several areas. 420 steel is one of the easiest blades to sharpen. It is such a soft yet tough steel; it will sharpen within moments on any stone or sharpening device. The ease of sharpening is a good way to learn how to take care of a knife. Not to mention, 420 steel is a forgiving knife that won’t rust and corrode like other knives.

This is due to the high chromium content of 420 steel; this high chromium content provides it with its amazing stainless steel properties.

Unlike most blades, 420 steel will not rust and corrode over time as quickly. It’s excellent for a kid just learning the ropes of knife collecting or just using a starter knife out on the farm!  If he leaves it sitting around, it won’t deteriorate (rust) as quickly as most higher-priced, harder steels. 

420 steel also makes for an excellent diving knife due to stain resistance and corrosion resistance — it will not rust while submerged in water.

The ease of sharpening, stain resistance, corrosion resistance, and cost will make for an excellent starter knife. 420 is often used in cheap balisongs.

Downsides of 420 Steel

Even with all the benefits of 420 steel, it still has some negatives to deal with. Due to the same strength that makes it easily sharpened, the softness of the blade will cause the knife to lose an edge. (This $50 folding knife outperforms $200 knives). The soft blade requires routine sharpening.

On another note, the softness of the steel means that the blade can be dented and dinged quite easily.

With the softness of the blade being the major downside of the blade, it makes for a poor survival knife, even with the other properties of 420 steel factored in. Frankly put, the 420 steel knife would not hold an edge for a week, nor would the initial edge be as sharp as a carbon steel blade.

In spite of this, there are knives that are made with 420 steel. 

I would not suggest you get one as your ACTUAL survival knife, but it would be an appropriate buy for someone like a responsible(ish) teen out on a farm who is looking for an introduction into knives/survival/outdoors just looking to wet his feet.  Here’s a great one for that purpose:

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Is 420 steel good for knives?

Overall, the 420 stainless steel makes a good knife due to its 50HRC, good toughness, and impressive resistance. 

It is an interesting knife if you are someone who has to handle food items while backpacking or a diver since it has high corrosion resistance and is suitable for humid conditions.

420 stainless steel equivalent

420 stainless steel vs. 440 stainless steel

420 stainless consists of a composition of 12-14% Chromium, 1% Manganese, 0.15% Carbon, 1% Silicon, and small amounts of Sulfur and Phosphorus. The 440 stainless steel has notably higher amounts of Chromium, ranging between 16 to 18%, and Carbon between 0.6% to 0.75%. 

This seemingly slight variation in chemical composition actually leads to different electrical and mechanical properties.

440 is a martensitic stainless steel that consists of high levels of Carbon and Chromium. The 440 stainless steel is quipped with the ability to reach and retain great levels of hardness as well as wear resistance. It is a magnetic steel in allconditions and the wear resistance is noted to be best when it is hardened. 440 stainless steel is known for having the highest level of hardness amongst all stainless steels.

420 stainless steel vs. 1095 carbon steel

The 1095 carbon steel consists of 0.90-1.03% of Carbon, 98.38-98.8% of Iron, less than 0.050% of Sulfur, 0.30-0.50% of Manganese, and less than 0.040% of Phosphorous.

The 1095 carbon steel plainly a high carbon steel that will hold a nice dge and will rust rather readily. Whereas, the 420 stainless steel is a martensitic stainless steel consisting of high carbon and high chromium levels. The 420 is considered a stainless steel though any steel can rust if not looked after properly, and it is much better in terms of corrosion resistance or rusting than the 1095 carbon steel. 

Best 420 steel knife

The Rescue Tactical Pocket Knife is one of the most popular knives with a 420 stainless steel blade. It features a 3.⅝-inch blade with a Tanto point shape for excellent piercing power and capability. The stainless steel blade is coated with black oxide which facilitates corrosion resistance while reducing light reflection.

The rescue pocket knife provides multiple functions which makes it an excellent investment for emergency situations or a little cook-up while camping. It also features a razor sharp seat belt cutter, a partially serrated blade, and a car window breaker point.

All of this ensures that you should be able to handle any emergency that comes your way.

Conclusion

The factors that should lead you towards a 420 blade are corrosion resistance and cost. These factors contribute to a fantastic knife that can be used in a wide variety of situations but excels at a few. 420 steel doesn’t make a good survival knife, but it makes one of the best diving knives you can buy.

It’d be hard to go wrong with buying a 420 steel knife for diving; after all, it has one of the best corrosion resistance of all the steels used for knives. All in all, it’s a great steel for the average user and even better for a young kid or teen being introduced to knives for the first time. It is also the steel of choice for a lot of machetes.

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