If you’ve spent any time around metalworkers or bladesmiths, you’ve heard people toss out numbers like 1018, 1045, 1095, 80CrV2, 15N20, 8650… and it can feel like a secret code.
The good news: it is a code—but it’s learnable. And once you understand the basics, picking steel becomes way less intimidating.
Steel isn’t “just steel”
In its simplest form, steel is iron + carbon. That’s it.
But carbon is a powerful ingredient. As you increase carbon content, steel generally becomes harder—which sounds great—until you learn the tradeoff:
- More carbon → more hardness
- More carbon → more brittleness
That’s the “catch.” Different projects require different balances of hardness vs. toughness, so manufacturers developed steels with varying levels of carbon (and later, additional alloy elements) to meet specific performance targets.
The 10-series: a great place to start
When you hear 10-series steels (like 1018, 1045, 1095), you’re usually dealing with simple carbon steels—primarily iron and carbon.
A handy rule of thumb in the 10-series: the last two digits roughly track carbon content.
- 1045 is around 0.45% carbon
- 1095 is around 0.95% carbon
So yes—those last two numbers matter.
A simple way to think about it:
- Low carbon (roughly 0.05–0.35%)
- Medium carbon (roughly 0.35–0.50/0.60%)
- High carbon (roughly above 0.50/0.60%)
Beginner-friendly tip: if you’re new to forging or metalworking and feel overwhelmed by options, starting with a mild steel like 1018 can be a low-stress way to learn tool handling, layout, and technique without “ruining” expensive material.
Alloy steels: when steel gets superpowers
Once you move beyond simple carbon steels, you’ll hear about alloy steels.
“Alloy” just means: we intentionally added other elements—like chromium, nickel, molybdenum, vanadium—to give steel properties it can’t get from carbon alone.
Those alloying elements can influence things like:
- hardenability (how deeply it hardens)
- toughness
- corrosion resistance
- wear resistance
- grain refinement
- high-temperature performance
Reading a few common alloy steels
8650: what those numbers are hinting at
A steel like 8650 is often explained as:
- the first digits point toward a family where certain alloys are typical
- the last two digits still relate to carbon (so “50” ≈ 0.50% carbon)
The key takeaway isn’t memorizing every family code—it’s understanding what the label is trying to tell you: carbon level + alloy “character.” This one is commonly valued for being tough and useful in applications where durability matters.
80CrV2: a “step up” that still feels familiar
80CrV2 is popular in bladesmithing because it behaves like a more capable cousin of the simple steels. The name itself is a clue: it’s a steel with chromium (Cr) and vanadium (V) additions.
In practical terms, steels like this are often chosen when you want:
- better hardenability than a simple carbon steel
- good edge stability
- solid toughness for working knives and hard-use tools
15N20: famous for Damascus
15N20 shows up constantly in pattern-welded (Damascus) work, largely because it includes nickel (N)—and nickel stays bright after etching, creating strong contrast between layers.
It’s often paired with a darker-etching steel (like a 10-series high carbon) to make patterns pop. If you’ve seen bold black-and-silver Damascus contrast, 15N20 is usually part of the recipe.
Stainless (AEB-L): not “better,” just different
Stainless steels are steels where corrosion resistance is a central goal—typically achieved through chromium content and the way the steel forms protective oxides.
AEB-L gets mentioned a lot because it’s a respected stainless in the knife world when heat treated correctly. The tradeoffs are real, though: stainless choices often involve balancing corrosion resistance, toughness, and ease/precision of heat treat.
The simplest way to think of stainless in a beginner framework:
- It’s great when you care about corrosion resistance.
- It rewards good heat treating practices.
- It’s not automatically “superior”—it’s just built for different priorities.
Damascus steel: the “how,” not the “what”
Damascus (pattern-welded steel) isn’t a single steel type. It’s a method—forge-welding layers of steel together into a billet (or canister), then manipulating those layers to create patterns.
When people talk Damascus in a practical shop sense, they’re usually talking about:
- layer choices (contrast + performance)
- weld quality
- heat treat compatibility
- final use case
A common pairing is something like high-carbon + 15N20 (for contrast and performance).
Tool steels: built for abuse (and a bit picky)
Tool steels are designed for tools that see impact, heat, abrasion, and repeated stress. They often contain strong carbide-forming elements like tungsten, molybdenum, chromium, and vanadium.
Two examples that come up often:
W2
“W” is commonly associated with water-hardening, but reality is more nuanced—depending on your process and part geometry, it may be quenched in oil as well. Either way, it’s a classic “tool steel” category where heat treat matters a lot.
S7
S7 is often described as a shock-resistant steel—useful in tooling where impact toughness matters (think punches, chisels, hot-work tooling, etc.). These are steels that can shine in the right job, but they’re also less forgiving if your heat treat is sloppy.
The “miracle steel” myth
People love searching for the best steel—the one steel that will magically work for everything.
But steel doesn’t work like that.
The better question is always:
“What am I making—and what does it need?”
A sword, a chisel, a knife, a bracket, a marshmallow fork… these all ask for different combinations of:
- hardness
- toughness
- flexibility
- wear resistance
- corrosion resistance
- ease of fabrication
Start with your project, then pick the steel that matches the job.
A simple way to choose steel (without getting lost)
If you want an easy process:
- Define the job
- cutting edge? impact tool? decorative? structural? corrosion exposure?
- Choose your “family”
- simple carbon (10-series), alloy (80CrV2, 8650), stainless (AEB-L), tool steels (W2, S7), or Damascus (process-based)
- Match carbon + alloying to the need
- more carbon generally supports higher hardness
- alloying can boost hardenability/toughness/wear/corrosion resistance
- Pick the simplest steel that gets the job done
- simple steels build skill fast
- specialized steels shine when you’re ready to control process tightly
Check out a downloadable version of the article from our magazine here:
https://www.flipsnack.com/FBBBAB77C6F/steel-101
Originally published on Kilroy’s Workshop on Substack.
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