What is 420j2 Steel?

420j2 is inexpensive steel with good corrosive resistance in mild temperatures. It’s also resistant to carbonic acid, dilute nitric acid, detergent solutions, food solutions, and ammonia.

It is magnetic. For instance, screwdrivers made from steel can help pick screws up easier.

Another feature is that the 420j2 possesses impact-resistant properties in tampered conditions and is more durable compared to the 440 grades.

Based on the HRC scale, the 420j2 has a hardness of 40. The 420j2 steel is known by other names like SAE 51420, EN56D, and AISI 420.

Here are a few products that use it:

  • Kershaw Folding Fillet (1258X), K-Texture Knife; Flexible and Corrosion Resistant 420J2 Stainless Steel Blade


  • Lock&Lock Premium Korean BBQ Bulgogi Kalbi Stainless Steel (420J2) Scissors – Meat Cutting Shears


  • Nail Clippers for Thick Nails Perfect Fingernail Clipper Toenail Clipper Set with Nail File for Adult Sharp 420J2 Steel




The steel has a remarkable hardening capability and can make an all-good purpose knife. It can easily be machined, and this increases its usefulness.

Corrosion resistance

This is where the carbon alloy shines – corrosion is a big issue in steel. The reliability of a knife is to stay sharp, irrespective of the environment it’s used in. Keep in mind both carbonic and nitric acids do not comprise the 420j2.

Did you know the further elements go on the periodic table, the more reactive they will be to acids? This explains why carbon reacts strongly with acids.


The 420j2 steel has a carbon content of 0.36%, while the 440A has twice that. From this number, it means the 420j2 is softer than the 440A. Also, chipping on the blade is less frequent – this is a well-known engineering fact. If more pressure deforms on the blade, you can be sure it won’t break.

The same applies to steel blades. If you put too much pressure, it won’t break.

Easy to work with

While low carbon doesn’t limit the resistance and toughness to corrosion, it makes the steel easier to mold.


The 420j2 steel has a decent hardness thus easy to sharpen. It lets you entertain the sharp edge of the standard sharpening tools.

Edge retention

The edge retention comes in handy when the steel has low carbon in it. It’s no wonder the 420j2 model has low edge retention.


This steel is durable and is incredibly tough but can break under impact.




As with the other 400 series, the 420j2 consists of carbon (0.15% to 0.36%). With a low amount of carbon, you get greater toughness. This makes the tools made from steel resistant to chipping.

Another important component is chromium (14%). This makes the stainless steel resistant to corrosion and is great for kitchen work.

To boost tensile strength, the 420j2 consists of 1% manganese. While most carbon types consist of 0.3% manganese, the low carbon helps to compensate for the low carbon.

This steel also comprises 1% phosphorus – it enhances corrosion resistance and increases strength. Again, adding more phosphorus in the mix helps to compensate for the low carbon level.

To enhance fracture toughness, the steel comes with 1% nickel. It boosts resistance too.

The other crucial component is Silicon at 1%. It helps to take the oxygen levels in molten steel and increases hardness. However, the effect is not as great as manganese.

Finally, the 420j2 steel comprises 0.03% sulfur to boost the machinability of steel.

While these values will depend on the manufacturer, all stainless steel has a high amount of chromium and this is what gives a chrome finish. All metals except sulfur and silicon are direct components of steel. And because they work as deoxidizers, they fuse with the oxygen used during the process.

Another crucial thing to note is that the sulfur and silicon compounds will drop depending on the alloy – this happens during the manufacturing process. Any de-oxidation makes the metal weaker.

The 420j2 steel is equivalent to 3Cr13. They fall in the same price range and have a similar chemical position. When you compare it with other steels, you can be sure the 420j2 model excels in terms of toughness, easy sharpening, and corrosion resistance.

You can compare with models AUS8, 8 cr13 MOV, and 420hc. While these metals may feature the same chemical components, they have low chromium and high carbon components. But again, the metals score poorly in terms of wear resistance and edge retention.




The 420j2 has a hardness of 40 on the HRC scale. It’s pure and performs well when heat treated. The steel is 0.3% carbon, 14% chromium, 1% nickel, 1% magnesium, and 1% silicon.



How it’s made

The process starts by heating the steel to 730-790  degrees F. For the best results, you should maintain the same temperature. The next step is heating and air cooling the steel. It involves heating the metal throughout 840-900 degrees Celsius.

The hardening process involves reaching 950 -1020 degrees Celsius. But you should maintain the same temperature throughout the heating process. After that, you should place the steel in an air cooling system. If you have to tamper with it, you should work on it while still warm.

The 420j2 steel requires proper hardening to ensure the best all-around properties. Otherwise, you may compromise the critical characteristics of the steel. It’s excellent for making hunting knives, household knives, and woodcarving tools.

The 420j2 is not recommended for welding in hardening or annealed conditions. If you’re not careful, it can lead to the formation of brittleness. High carbon content means a higher risk of cracking. But despite this, you can still weld better compared to the 440C grade.




The 420j2 is used to make precision surgical instruments (forceps, specula, and clamps) but you have to treat it in a harsh environment.

If you’re looking for budget knives, you can’t go wrong with this steel. It works well with knives that are exposed to acids that make food palatable. Unlike the 440 grades, this material is great for daggers, haircutting scissors, swords, and anything that require a polished look.

The 420j2 model is corrosion-resistant and offers great toughness. As an example of low-end stainless steel, it can be used to make surgical knives, hunting knives, or tactical knives.


Carbon Steel used for Knife making:
ATS 34

Stainless steels used for knives: