Carbon steel is characterized by a high carbon content, usually up to 2.1% of its weight. The American Iron and Steel Institute (ASISI) further defines carbon steel by meeting the following criteria:
- No minimum content requirement for chromium, cobalt, nickel, titanium, tungsten, vanadium or other corrosion-resistant metals.
- Minimum required copper content must not exceed 0.40%.
- Maximum content of manganese must not exceed 1.65%.
- Maximum content of copper must not exceed 0.6%
- Maximum content of silicon must not exceed 0.6%
So, what benefits does carbon steel offer? The use of a high carbon content changes the characteristics of steel. More specifically, it becomes stronger and harder. This is why many swords, knives, and other bladed weapons are produced with high-carbon steel. In feudal Japan, swordsmiths pioneered a special type of high-carbon steel, tamahagane, for use in weapons like the katana.
Does carbon steel rust? Yes, carbon steel does rust because it lacks the corrosion-resistant properties of its stainless steel counterpart. Although it’s stronger and more durable than stainless steel, carbon steel may rust and corrode when exposed to moisture. Even small amounts of moisture, including moisture vapor in the air, can cause carbon steel to rust. Furthermore, carbon steel is less ductile than stainless steel.