If you have previous experience using affordable knives with great performance, then most of the knives you have been using are made out of 420J2 steel. Even if the knife steel is affordable you will witness a satisfying performance of the steel in corrosion resistance and many other properties. The 420J2 series is the most affordable one amongst all the other ones of the famous 400 series. Let’s explore in depth the chemical composition and properties of steel.


What is 420J2 Steel?

420J2 falls into the affordable scale since it is low-end steel. Steel is a stainless alloy that is used for general purposes and not to accomplish anything complicated. There are others names as well for 420J2 like AISI420, EN56D, and SAE 51420.


The steel is a member of the 4000 series which is a family of surgical steels that are well known to have great corrosion resistance, machinability and ease of sharpening. Giving the steel a nice polished surface is an easy job as you will find it smooth to grind the steel.


420J2 is mostly used for the making of surgical tools because of its great attributes in corrosion resistance and machinability. Surprisingly, 420J2 is not a tool steel but regular affordable steel with beneficial features. Apart from surgical tools, 420J2 is widely used for the manufacturing of diving knives, domestic scissors, kitchen knives, outdoor knives, daggers and even scissors for hair cutting. Mostly you will see steel being used for the manufacturing of blades that is suitable for light to medium duty.


Another beneficial feature of steel is that it is magnetic. Thus, tools made out of steel will have some magnetism induced in them. Initially, steel was not created for making knife blades, but all the favourable properties of 420J2 make it a popular choice amongst knife makers.


Chemical Composition:

420J2 is classified as stainless steel as it has the required percentage of chromium in its chemical composition. The carbon content is less and the steel falls into the low-end scale.

  • 0.32% of Carbon: Increases resistance of the steel towards corrosion and wear and boosts the hardness level of the steel.
  • 14% of Chromium: Boosts tensile strength to maximum possibility, and increases edge retention, hardness, toughness and resistance towards corrosion and wear.
  • 1% of Nickel: Works for improving toughness.
  • 1% of Manganese: Increases wear resistance, forge ability and hardenability.
  • 1% of Silicon: Improves steel strength.
  • 0.04% of Phosphorus: Increases steel strength.
  • 0.04% of Sulphur: Improves machinability.


Steel Hardness:

According to the Rockwell C scale, the maximum hardness rating of 420J2 is up to 56 HRC. To reach that rating manufacturers need to provide adequate heat treatment. The hardness rating of 420J2 falls into the not-too-low or high range. The reason behind the low hardness rating is the low carbon percentage of the steel.


The rule of steels is to have a higher hardness level depending on higher carbon percentage and heat treatment provided. Due to its low hardness level, 420J2 is the cheapest steel available in the 400 series.


Steel Properties:

  • Incredible toughness: It does not come as a surprise that 420J2 is bound to have incredible toughness due to low hardness and the inversely proportional relationship between hardness and toughness. The incredible toughness level makes 420J2 a very durable steel that can endure heavy duty and work under tough impact. The edge of the steel will not chip or break upon regular use.
  • Great corrosion resistance: After toughness, corrosion resistance is the second property that makes 420J2 stand out. The great corrosion resistance of the steel allows it to keep rust and corrosion while fighting off reactions from ammonia, acids, crude oil, cleaning liquids, vinegar, moisture, and petroleum-based items. The low percentage of carbon also enhances the corrosion resistance of the steel. The steel does not have enough carbon to react with the acids and cause corrosion. And of course, the high chromium percentage works for corrosion resistance and increasing steel strength.
  • Ease of sharpening: You will not need much effort for sharpening a blade made out of 420J2 as the steel is not very hard. With the help of any regular sharpener, you can give the edge your desired sharpness. But it does lose its sharpness pretty often which will cause you to require frequent sharpening.
  • Weak wear resistance: It is not unexpected for 420J2 to have poor wear resistance due to its low hardness rating due to low carbon content. Wear resistance is directly linked with the hardness level of steel.
  • Weak edge retention: Weak edge retention works as a setback for the steel and makes it lag in performance. The low carbon percentage of the steel degrades the capacity of the steel to retain its edge.


420J2 vs. Other Knife Steel Options:

420J2 versus 420HC

Even though both the steels belong to the same series you will witness a lot of differences in their performance in various aspects. 420HC is better at edge retention and wear resistance than 420J2 due to its higher carbon percentage in it. But 420J2 wins at corrosion resistance and toughness level than 420HC.


420J2 versus 8Cr13MoV

8Cr13MoV is a Chinese steel with a greater carbon percentage that has better edge retention and wear resistance than 420J2. Both of the steels portray similar performance in corrosion resistance. But in terms of toughness and ease of sharpening 420J2 takes the crown. Furthermore, the steels have a similar price range but 8Cr13MoV is the more affordable one.


420J2 versus AUS 8

Both sheets of steel are products of Japan. But AUS 8 has a higher hardness level making it better at edge retention and wear resistance than 420J2. AUS 8 also has better corrosion resistance but the toughness level is similar to 420J2.



So, Is 420J2 Steel Good?

Yes, 420J2 is a good knife steel if you are looking for an affordable option. The steel is great for the manufacturing of knives that need to come in frequent contact with moisture. As the great corrosion resistance ability of the steel allows it to tackle rust and corrosion. On the contrary, the steel is poor at edge retention and wear resistance but toughness and ease of sharpening do help with covering up these flaws to some extent.




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