What are alloying elements? What are the alloying elements often added in alloy steel? How to classify it according to its interaction with carbon?

The alloying elements often added in alloy steel are molybdenum, silicon, nickel, chromium, manganese, tungsten, vanadium, titanium, aluminum and so on. Chromium, molybdenum, tungsten and vanadium have little strengthening effect on ferrite, but they tend to form carbides. Silicon strengthened ferrite is the most; Nickel moderately strengthens ferrite; V and Al have great influence on grain refinement. Ti has the greatest effect on grain refinement; The grain refinement effect of Mo and w is moderate; Mn can promote grain growth, and there is almost no tendency to form carbide; Strengthening ferrite plays a great role.