How do the properties of steel change with the increase of carbon content?

1. Its plasticity gradually decreases and its brittleness increases. Obviously, low carbon steel has better plasticity than cast iron. 2. The hardness of steel is improved; 3. Processing will become difficult; 4. When the carbon content increases to a certain extent, heat treatment will be more difficult to obtain (for example, the quenching performance of medium carbon steel is better than that of high carbon steel, but cast iron cannot be quenched); 5. The welding performance becomes worse; Thank you. No kidding!