The most conspicuous difference between carbon steel and mild steel is the amount of carbon they contain. Carbon is the primary element in steel but the amount of carbon varies from one type to the other.
Mild steel is a type of carbon steel that contains a very low amount of carbon, about 0.16 –0.29% of carbon hence, Mild steel can not be hardened by heat treatment Carbon steel has more carbon content, about 2% and this allows it to be hardened and tempered.
Mild Steel is very cheap and easy to work with, relatively easy to cut and is most commonly used. It is soft, plastic and flexible but has very low tensile strength. Mild carbon cannot be hardened by heat treatment due to the low percentage of carbon.
Higher carbon steels have better mechanical properties mainly high ductility, strength and hardness but are more expensive to produce and more difficult to work with. Carbon steel is used mostly when high strength components are required e.g. springs, driveshafts, gears, bearings etc. There are also classes of steel that contain high quantities of alloying elements other than carbon -vanadium chromium, nickel which are manufactured for definite applications.
Carbon steel is used for the manufacturing of bearings, cutting tools, very high strength and hardness components, corrosion resistance, high-temperature application, and very high wear-n- tear. Carbon Steel is made into pulleys and drives shafts while Mild steel is forged and fabricated into steel plates, round bars, flanges, steel pipes. All the products above can also be made by carbon steel, but we can use carbon steel products at high pressure not mild steel. So basically only working conditions differ between Carbon steel and Mild steel