SK-85 is the new JIS name for SK5. It is a Japanese high-carbon water hardening non-stainless tool steel somewhat comparable to 1085 carbon steel. It's AISI name is W108 steel. It is used in knives, springs, machetes, axes/hatches and other cutting instruments and tools. Its performance and application can vary quite a bit depending on the heat treatment. Composition: 0.80-0.90 Carbon (C), 0.00-0.30 Chromium (Cr), 0.10-0.50 Manganese (Mn), 0.00-0.25 Nickel (Ni), 0.10-0.25 Silicon (Si), 0.00-0.25 Copper (Cu), 0.03 Phosphorus (P), 0.003 Sulfur (S).
