If you are in search of steel that has unbeatable capability in corrosion resistance, then it is 420 steel that you need for the manufacturing of your knife blade. This amazing stainless steel is an affordable option for the making of knife blades with great properties, we have listed down details about the steel so you can decide whether it is good knife steel or not.

What is 420 Steel?

420 steel belongs to the 400 series of stainless steel, the chemical composition of the steel states that it is AISI martensitic steel category. 420 steel has more carbon content compared to 410 and 416 which belong to the 400 series of the steel. You can harden 420 steel at a higher level by providing proper heat treatment to the steel.

As 400 steel series have amazing properties like high corrosion resistance, great machinability and easy-to-sharpen knife makers love it for manufacturing blades. A special quality of the 400 series is that it stays magnetised even after the steel is forged into shape or if the hardness level of the steel is increased.

The manufacturing process of 420 steel is inexpensive which makes it popular for use in the knife-making industry. You will see the use of steel in the manufacturing of cutlery, diving knives, valves of needles, razor blades and scalpels.

Chemical composition:

420 is stainless steel, with various elements present in its chemical composition. 420 steel does have more carbon content in its chemical composition compared to 410 and 416 steel. Yet, the carbon content of 420 is less than other steels of the 4000 series. We have listed down details regarding the elements and the properties of the steel.

  • 15% of Carbon: Works for increasing hardness and to make the steel resistant to corrosion and wear.
  • 13% of Chromium: Increases corrosion resistance, edge retention, hardness level and strength of the metal.
  • 1% of Manganese: Increases hardenability and enhances the resistance of the steel to wear.
  • 1% of Silicon: Increases corrosion resistance and strength of the steel.
  • 04% of Phosphorus: Adds strength and machinability to the steel.
  • 03% of Sulfur: Increases machinability.


The hardness of the steel:


According to the rating shown on the Rockwell C scale, the minimum hardness rating of 420 steel is about 50 HRC. With the help of heat treatment, you can increase the hardness rating of the steel up to 57 HRC. Since the rating of the steel is not above 61 HRC You can already deduce that the steel has a soft nature.


Properties of 420 steel:


  • Great Toughness: 420 steel have a great amount of toughness since the hardness level is low. The hardness level and toughness level are indirectly proportional to each other, which defines the toughness level of 420 steel. The steel is capable of resisting breakage, chipping and cracking upon impact easily.
  • Weak Wear Resistance: As the 420 steel is soft because of having a low hardness level, the wear resistance of the steel is also low.
  • Poor Edge Retention: Due to the low hardness level of the 420 steel, the steel is not able to hold sharpness for too long. You will need to resharpen the edges of the steel after a couple of uses.
  • Great Corrosion Resistance: 420 steel is stainless and it also has a great amount of chromium which gives it the capacity of resisting corrosion and rust to a great extent. You will see knife makers using the steel for knives like carving knives, diving knives, table knives and various other knives that may come into contact with humid or saltwater conditions. However, 420 steel is weaker than 410 and 430 in terms of corrosion resistance.
  • Ease of Sharpening: As 420 steel has a low hardness level and has a soft build-up compared to other steels, it is very easy to sharpen. You don’t need to own a very expensive sharpener for giving the steel a proper edge, as the steel can gain sharpness with the help of normal abrasives. The 420 steel easily retains back sharpness at a quick speed compared to other steels.


Comparing 420 steel with other options:


420 vs 1095:


Like 420 steel 1095 also has high carbon content but it has a greater hardness level making it better in edge retention and resistance to wear compared to 420. However, the manufacturing of 1095 is more expensive compared to 420. On the other hand, 420 steel has a higher amount of chromium in its chemical composition making it better in corrosion resistance. Since 420 is hard than 1095 it is also easier to sharpen.


420 vs 440:


Both of the steels are martensitic according to their chemical composition. Yet, you will see that the amount of carbon is higher in 440 compared to 420 which contributes to increasing its hardness, wear-resistance and edge retention as well. 440 also beats 420 in terms of corrosion resistance as the chromium content is high in its composition. On the positive side, 420 beats 440 in toughness level and also it is easier to sharpen compared to 440.


420 vs AUS 8:


AUS8 steel differs from 420 steel in terms of chemical composition. The carbon and vanadium content is present at a higher percentage in AUS8 compared to 420 which makes the steel better in edge retention, wear resistance and toughness. However, it is easier to sharpen 420 steel compared to AUS8.


So, is 420 Steel Good Knife Steel?


You can consider using 420 steel but it should not be your first choice for manufacturing knife blades because of poor performance in many aspects. The steel does not have the required edge retention of a knife maker as you will need to sharpen very often. Yet, the steel is cheap with satisfying corrosion resistance which is not enough for use to manufacture knife blades.


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