Like identity card of each person, chemical composition is the only feature that identifies the specification of material. Lots of steel alloys could be forged, such as 1035 steel, 1045 steel,1020steel, 20CrMnTi, 20Cr, 40Cr, Q235, Q345, 20CrMo, 30CrMo, 35CrMo, 42CrMo, ect. For steel forgings, spectrum analysis is the most widely used method to do material inspection.