Knife Steels
Selecting the right steel for the job is half the challenge and will determine how strong your blade is, and how long it will hold an edge for.
Steel is generally a mix of iron and carbon, with various other elements that enhance the properties of the steel e.g. chromium improve the corrosion resistance of steel.
Edge geometry plays an important role in how long your edge will last. A thin sharp edge will not stand up to the rigors of chopping wood and a beefy blunt edge will be poor at cutting tomatoes. Choose the right edge angle for the use of the blade.
Steel choice is a balance of:
- Edge retention – how long your blade will hold an edge.
- Toughness – resistance to breaking, cracking and chipping. Large knives need toughness.
- Hardness – the indentation hardness of a steel, measured on the Rockwell scale (HRC). Most commonly, knives are between HRC56-62. HRC52-55 is considered low for a blade.
- Corrosion resistance – stainless steel is resistant to corrosion but not rustproof. As you improve corrosion resistance, you start to decrease the other desireable properties.
- Wear resistance – resistance to abrasive wear. Elements like vanadium are added to improve toughness.
The above properties are not mutually inclusive and it’s often a trade-off of one property against another. The end use of the blade will ultimately influence your choice.
Another factor to consider is how easy it is to work and heat treat. If you’re just starting out, choosing a steel that is easy to forge and easy to heat treat will greatly improve your chances of success and be less frustrating. Fortunately such steel is easy to come buy and pretty cheap too.
Steels
Simpler steels are easier to forge and more forgiving in heat treats. Below, the poor corrosion resistance just means you’ll need to take more care of the knife by oiling it up after use to prevent rusting. They still make outstanding knives. Stainless steels are tricky to heat treat so should be avoided initially if you intend to heat treat yourself.
| Steel | Forging | Heat treat difficulty | Corrosion Resistance |
|---|---|---|---|
| 1070-1084 | Easy | Easy | Poor |
| 1095 | Easy | Medium | Poor |
| 5160 (spring steel) | Easy | Easy | Poor |
| 80crV2 | Easy | Easy | Poor – higher than 1095 |