PC wire is a single, cold-drawn, high-carbon steel wire that has undergone a thermo-mechanical treatment to improve its tensile strength and reduce load relaxation. It can have a smooth or indented surface to enhance its bond with concrete. 

Key properties:

1. High tensile strength: Provides strength and reinforcement to concrete structures.

2. Low relaxation: Retains the prestressing force over a long period of time.

3. Thermo-mechanical treatment: The process of heating and stretching the wire increases its yield strength