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Do you have an old diving knife that does not succumb to corrosion? If yes, there is a high probability that its blade being made using the 420 steel.

It is an affordable steel option. Let’s dive deeper to know about its characteristics.

What is 420 Steel?

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420 is an AISI martensitic steel material that belongs to the 400 series of steels. It is a higher carbon form of the former 410 and 416 stainless steels, which is possible to harden further with proper heat treatment.

The 400 series is quite popular among knife makers as well as users due to easy machinability, higher corrosion resistance, and ease of sharpening. These 400 steels are magnetic in the hardest and forged states.

The 420 steel is widely used to make budget-friendly knives. It is most commonly used for making diving knives, cutlery, needle valves, razor blades, and surgical scalpels.

Chemical Composition

420 belongs to the group of stainless steels. Although the carbon content is more than 410 and 416 steels, it is still less than other steels of the same family. Following are the different elements that make up this stainless steel:

  • 0.15% Carbon: For increased hardness as well as resistance to wear and corrosion
  • 13% Chromium: For increased tensile strength, hardness, edge retention, and resistance to corrosion
  • 1% Manganese: For great resistance to wear and increased hardenability
  • 1% Silicon: For increased strength as well as resistance to corrosion
  • 0.04% Phosphorus: For increased strength as well as machinability
  • 0.03% Sulfur: For increased machinability

Steel Hardness

On the Rockwell C scale of hardness, the 420 stainless steel has a minimum rating of 50 HRC. With a proper heat treatment, this steel can gain a hardness rating of up to 57 HRC. This range of hardness indicates that this steel is soft.

Steel Properties

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  • Good Toughness: As 420 is not very hard, it is significantly tough. In the world of steels, the softer the material, the tougher it is! Although the level of toughness is not premium, it is significant enough to resist chipping, breaking or cracking when abused.
  • Low Wear Resistance: The harder the steel, the better is its ability to resist wear and tear. As the blade of a 420 stainless steel knife is soft, its wear resistance level is low.
  • Edge Retention: 420 steel knife will not hold its sharp edge too well for a long time as it is soft. In other words, you will have to sharpen its edge frequently.
  • Great Corrosion Resistance: All stainless steels are known to ensure great resistance to corrosion. This steel satisfactorily resists corrosion or rust in the hardened state. This is why this steel is used in making diving knives, carving knives, table knives, and other tools vulnerable to rust. The corrosion-resistant power of 420 is less than that of 430 and 410 steels.
  • Ease of Sharpening: Being less hard and softer than many other steels, the 420 stainless steel is super easy to sharpen. It is so easy that even old abrasives will do the job for you. No matter which sharpening tool you use, you will be able to obtain a sharp edge quickly.

420 vs Other Knife Steel Options

420 vs 1095

1095 is high carbon steel that is prone to rust but will retain a keen edge. On the other hand, 420 is a high-chromium material. So, in terms of corrosion resistance, 420 wins over 1095. Further, it is easier to sharpen than 1095. However, in terms of edge retention and wear resistance, 1095 is better. Usually, 1095 steel knives are costlier.

420 vs 440

Both steels are martensitic. However, the amount of carbon is more in 440 stainless steel than in 420, due to which it is a harder option with higher wear resistance as well as better edge retention abilities.

On the other hand, 420 is tougher and is easier to sharpen than 440 steel. 440 is known to have greater resistance to corrosion. The credit goes to the higher chromium amount than in 420.

420 vs AUS 8

AUS 8 performs better than 420. It contains more carbon along with vanadium, the combination of which ensures more toughness, better wear resistance, and more edge retention ability than 420. On the other hand, 420 is easier to sharpen.

So, is 420 Steel Good?

420 stainless steel is a cheap steel good at corrosion resistance. However, it needs frequent sharpening. 420 steel knives are dirt cheap, but should not be your first choice for anything.