1. Introduction
（1）Composition
S45C is primarily composed of Carbon (C), with the carbon content being approximately 0.45%. It also contains small amounts of Silicon (Si), Manganese (Mn), Phosphorus (P), and Sulfur (S).Trace residual elements such as Chromium (Cr), Nickel (Ni), Copper (Cu).
（2）Performance Characteristics
S45C has high strength, hardness, and wear resistance, but also has low toughness. Heat treatment can achieve even higher hardness and improved wear resistance. This steel has good machinability and is relatively inexpensive, making it an economical engineering material.
2. Applications
S45C is widely used in machinery manufacturing, construction, tools, and other fields.For example, it can be used to manufacture mechanical parts such as shafts, gears, pins, connecting rods, nuts, and bolts. In addition, it can also be used to manufacture tools such as knives, measuring tools, and molds.
3. Summary
S45C is a medium-carbon steel with high hardness and strength, but also low toughness. Its good machinability and relatively low price make it an economical engineering material.