Classification of alloy steel: According to the content of alloying elements: low alloy steel (total alloy elements less than 5%), medium alloy steel (total alloy elements 5%-10%), high alloy steel (total alloy elements more than 10%). According to the composition of alloying elements: chromium steel (Cr-Fe-C), chromium-nickel steel (Cr-Ni-Fe-C), manganese steel (Mn-Fe-C), silicon manganese steel (Si-Mn-Fe-C) . According to the normalized or as-cast structure of the small sample: pearlitic steel, martensitic steel, ferritic steel, austenitic steel, ledeburite steel. According to the application: alloy structural steel, alloy tool steel, special AISI 8620 Low Alloy Steel Plates.With the development of science, technology and industry, higher requirements are put forward for materials, such as higher strength, high temperature, high pressure, low temperature, corrosion resistance, wear resistance and other special physical and chemical properties. To meet…