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BG42 Steel: Is it a Good Knife Steel?

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Bob Loveless, regarded as one of the most innovative custom knife makers in the world, had switched from ATS-34 to BG42 steel for his knives. This itself speaks very high of this steel. However, the higher cost, manufacturing difficulty, and limited supply diminished the popularity of BG42.

The good news is that there is a powder metallurgical version of this steel named CTS B75P available, but you hardly find mass-produced knives with this steel.

What is BG42 Steel?

Chris Reeve sebenza BG42
Source: Bladeforum

Originally made by Latrobe that was sold to Carpenter, BG42 is martensitic high-speed steel that is stainless. It was formulated for use in the structural components required in the aerospace industry and for making high-performance bearings. This steel is also preferable for making knives.

BG42 goes through the double vacuum melting technology, hence it is highly pure. This technology includes Vacuum Arc Remelted (VAR) and Vacuum Induction Melted (VIM) processes to deliver an extremely high level of cleanliness required for fatigue-critical tasks.

BG42 was not widely used in making production knives, unlike S30V or 154CM. It was used mostly by upscale brands such as Mercwerx and CRK. A few limited knives are there from Buck’s Strider limited edition along with some Spyderco Sprint knives.

For a short time, it was regarded as the super steel when Chris Reeve Knives added it to their Sebenza. Later, CPM S30V replaced BG42 as the preferable stainless steel. However, a few collectors still go for the traditional BG42 Sebenzas instead of the modern S30V ones.

Carpenter now makes a Powder Metallurgy (PM) version of BG42, which is CTS-B75P. This new version is not vacuum melted.

Chemical Composition

BG42 has enough chromium content, due to which it is classified into the group of stainless steels. Following are the different elements of this stainless steel:

  • 1.15% Carbon: For enhanced hardness as well as resistance to wear and corrosion
  • 14.5% Chromium: For enhanced tensile strength, edge retention, and resistance to corrosion and wear
  • 4.00% Molybdenum: For enhanced machinability and strength at high temperatures without inducing brittleness
  • 0.50% Manganese: For the enhanced hardness
  • 0.30% Silicon: For enhanced resistance to corrosion and strength
  • 1.20% Vanadium: For enhanced resistance to wear and hardenability

Hardness

On the Rockwell C scale of hardness, the BG42 stainless steel has a rating ranging from 61 to 62 HRC. The credit for high hardness goes to the high carbon content along with the substantial amounts of molybdenum, vanadium, and manganese.

BG42 Steel Properties

Spyderco Military BG42
Source: TwojStary
  • Toughness: Surprisingly, this stainless steel is significantly tough despite being very hard. The credit for this goes to the suitable combination of vanadium, molybdenum, and manganese. This not only improves hardness but also toughness. Thus, it is less likely for a BG42 knife to chip, break, or crack.
  • Excellent Wear Resistance: The credit for this goes to the high level of hardness. The mix of vanadium, molybdenum, and chromium provides sufficient carbide volume to ensure great resistance to wear.  Vanadium carbides are very hard; they are harder than chromium carbides! BG42 is resistant to wear to such an extent that it is tough to sharpen its blade.
  • Great Edge Retention: It is a fact that the harder the steel is, the better is its ability to keep wear away. This applies to BG42 steel. The hard carbides and their sufficient volume are responsible for this benefit. In other words, this steel retains a sharp edge for a long time.
  • Fair Corrosion Resistance: BG42 is stainless. Apart from the high chromium content, molybdenum in its chemical composition also enhances its level of corrosion resistance. The blend of good corrosion resistance and excellent edge retention makes this steel an upgrade form of more commonly-known options like 440C.
  • Ease of Sharpening: As BG42 is truly hard, it is not easy to sharpen the blade. You will need the right sharpener (go for diamond) and skillset. However, you will not have to sharpen this blade frequently due to its excellent edge retention ability.

Comparison With Other Knife Steel Options

BG42 vs 154CM

The BG42 contains vanadium, which is not present in 154CM. Thus, it’s more resistant to wear than 154CM. It also ensures better edge retention than 154CM. On the flip side, BG42 is more difficult to sharpen than 154CM.

BG42 vs S30V

BG42 is tougher. It is also known to take a finer edge than S30V and retain a sharp edge for as long as S30V. However, S30V is more resistant to wear. On the other hand, BG42 is more resistant to stains than S30V.

BG42 vs ATS 34

BG42 is considered similar to ATS34, but it has double manganese and a high amount of vanadium, an element not present in ATS34. Thus, you can expect it to retain a sharp edge longer.

The presence of high vanadium content and the clean VIM/VAR processes make BG42 tougher than ATS34. It is also more resistant to corrosion than ATS34.

So, is BG42 Steel Good?

High hardness, excellent edge holding ability, good toughness, average corrosion resistance, and fine grain structure make this stainless steel a high-performing option for knives that are made to take a harsh beating.

If you wish to try this steel to know why it was once popular, consider getting one of those old Sebbies, Buck’s Striders, or Spyderco Millie Sprints. You may still find a few knives with its PM steel version CTS-B75P.