CTS BD1 is a high-carbon stainless steel produced by the American company Carpenter Technology Corporation. It is a vacuum-melted steel that was originally developed for high-end industrial applications but became a popular "value" steel for the knife industry.
It is the predecessor to CTS-BD1N, which we discussed earlier.
Key Characteristics
High Corrosion Resistance: With nearly 16% Chromium, it is very resistant to rust and staining. It was originally used for parts like ball bearings in food-processing equipment, so it handles moisture and food acids exceptionally well.
Extreme Sharpness: BD1 has a very fine grain structure, which allows it to take a very keen, razor-like edge. It is excellent for slicing tasks.
Ease of Sharpening: This is one of its biggest advantages. Unlike "super steels," BD1 can be brought back to hair-shaving sharpness very quickly on standard sharpening stones.
Moderate Edge Retention: It is typically hardened to 56–58 HRC. While it holds an edge better than 420 or 440A, it does not stay sharp as long as higher-end steels like S35VN or its nitrogen-enriched successor, BD1N.
High Toughness: It is a stable, durable steel that is resistant to chipping during normal everyday tasks.
Chemical Composition
Carbon (C): 0.90% (Provides good hardness)
Chromium (Cr): 15.75% (High for excellent rust resistance)
Manganese (Mn): 0.95%
Molybdenum (Mo): 0.30%
Silicon (Si): 0.37%
Common Applications
Spyderco Knives: It was famously used for the original Spyderco UK Penknife and early versions of the Manix 2 Lightweight.
Budget EDC Knives: Many manufacturers used it as an "upgrade" over budget Chinese steels to provide a better-performing American-made alternative.
Kitchen Cutlery: Used in many quality household knives due to its balance of stain resistance and ease of maintenance. [15]
CTS-BD1 vs. CTS-BD1N
BD1 is the original version.
BD1N added Nitrogen, which allowed the steel to reach higher hardness (up to 60 HRC) and improved the edge retention significantly without making it harder to sharpen.