425M Steel: Is It a Good Knife Steel?

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Many Buck knives were made of 425M steel. Knife users have admired this steel on many forums, although it has some limitations. Let’s explore the chemical composition, properties, and performance in comparison to its peers.

What is 425M Steel?

SOUDAO Pocket Knife for Men 425M blade

425M is a martensitic low-end stainless steel that is a modified version of 420. This is why its name has M in it. Further, as the name indicates, this steel belongs to the 400 series of steels, a group popular amongst knife makers, because of its high resistance to corrosion as well as ease of sharpness.

You will find this steel in many Buck knives. In the early 1960s, the brand had started using 440C, a high-carbon (above 1%), high-chrome (above 18%) grade of steel. Although excellent steel, 440C has large carbides, thus the edge becomes dull quite quickly.

To overcome this issue, Buck shifted to the 425 modified steel in the mid-1980s. This homogenized steel has relatively smaller carbides than 440C.

Its predecessors 420 and 420J belong to the low-end tier of stainless steels. As they are soft steels with less hardness, they are very tough. They are also resistant to stains and are easy to process but are weak in terms of wear resistance. You can expect them to lose their sharp edge quickly via impact and abrasion. These steels are used in making cheap knives.

425M and its related steels such as 440A, 12C27, and 420HC form the next group. It is possible to harden them more than the former group to ensure improved strength as well as better wear resistance. However, the hardness is still just acceptable.

425M is commonly used in making budget knives, cutting tools, and blades demanding high corrosion resistance. AISI 425M is certainly an improvement over AISI 420 but is not enough to be a part of mid- or high-end steels.

Chemical Composition

The amount of chromium present in the chemical mix of 425M steel is greater than what is needed to be grouped into the family of stainless steels. Thus, 425M is stainless.  Below are the components that make up this low-end steel:

  • 0.4-0.54% Carbon: For more hardness, wear resistance, and corrosion resistance
  • 13-15% Chromium: For more edge retention, toughness, tensile strength, and resistance to corrosion and wear
  • 0.6-1.0% Molybdenum: For more hardness, hardenability, and toughness
  • 0.8% Silicon: For more resistance to corrosion as well as strength
  • 0.5% Manganese: For more strength, hardenability, and wear resistance
  • 0.1% Vanadium: For more strength, toughness, and wear resistance
  • 0.04% Phosphorus: For more strength, machinability, and hardness
  • 0.03% Sulfur: For improved machinability

Hardness

On the Rockwell scale, 425M stainless steel has a hardness rating range of 57-60 HRC. This range of high 50s is usually considered suitable for being recognized as a good knife steel. The exact hardness level will vary as per the heat treatment given. The credit for this range of hardness goes to good amounts of carbon, chromium, and molybdenum.

Properties

SOUDAO Fixed Blade Knives with Sheath 425M blade

  • Good Toughness: As a rule of thumb, hard steels are not tough. As the level of hardness is not high, 425M steel is tough. Although its level of toughness is not as great as other steels in the series due to the lack of nickel. Yet, it is tough enough to endure abuse to some extent.
  • Decent Wear Resistance: The carbon content is neither the best nor the worst, hence the hardness is just fine for good budget knives. Thus, this steel offers decent wear resistance power.
  • Okay Edge Retention: Less than 0.6% carbon available for producing chromium carbides that make any steel hard and consequently better at retaining a sharp edge. Hence 425M cannot retain a sharp edge for a very long time. As carbon volume is less, most of the chromium is then reserved for keeping corrosion at bay.
  • Excellent Corrosion Resistance: This is where 425M excels due to high chromium volume. Being stainless by having 13-15% chromium, this steel can resist rust quite well. This means it is good for making knives suitable for humid or even saltwater environments.
  • Ease of Sharpening: 425M steel is not as great as harder steels in resisting wear. Hence, you can sharpen it quickly using any usual sharpeners to get a very sharp edge. This is truly commendable given that this steel needs frequent sharpening.

Comparison With Other Knife Steel Options

425M vs 420

425M has more carbon and chromium content than 420, hence it is harder than 420. Thus, the modified steel  is better at wear resistance and corrosion resistance. Nevertheless, this makes 420 tougher as well as easier to sharpen than 425M. You will find both these steels in budget knives.

425M vs 440C

440C has more carbon (0. 95-1.20%), is better at wear resistance, and holds an edge for longer than 425M. However, sharpening it is harder.

So, is 425M a Good Knife Steel?

425M is budget-friendly stainless steel is good for knives suitable for humid or wet environments because of its corrosion resistance ability. However, just remember that it will not hold a sharp edge for long.