C45 bright bar is a type of mild steel bar that is similar to C40 bright bar but with a higher carbon content, which provides even higher strength and hardness. Here are some of its common uses:

1. Manufacturing of machinery components: C45 bright bar is commonly used in the manufacturing of various types of machinery components, such as gears, shafts, and axles, due to its high strength and hardness.
2. Construction industry: C45 bright bars are also widely used in the construction industry for making components such as bolts, nuts, and screws, which require high strength and durability.
3. Automotive industry: C45 bright bars are used in the automotive industry for making components such as crankshafts, camshafts, and steering components, due to their high strength and toughness.
4. Agriculture and farming equipment: C45 bright bars are used in the manufacturing of various agricultural equipment components such as plowshares, harrows, and cultivators, due to their high strength and durability.
5. Toolmaking industry: C45 bright bars are also used in the toolmaking industry for making various types of cutting tools, such as knives, saws, and blades, due to their high hardness and wear resistance.