Does my online steel price include tax, dear! Hello, I'm glad to answer your question. Pro ~ refers to the alloy of iron with carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S) and a few other elements. Steel is the general name of iron-carbon alloy with carbon content of 0.02%-2. 1 1%. The chemical composition of steel varies greatly. Steel containing only carbon element is called carbon steel (carbon steel) or ordinary steel. In actual production, steel often contains different alloying elements, such as manganese, nickel and vanadium, according to different uses. The application and research of steel has a long history, but before the invention of bainite steelmaking in the19th century, the production of steel was a high-cost and inefficient work. I hope my answer can help you! Do you have any other questions to ask?