4140 steel plate,42crmo steel plate,metal plate aisi 4140 belongs to medium hardenability steel,and carbon content within 0.38-0,43 %,chromium content within 0.80-1.10 % and Molybdenum content within 0.15-0.25 %.4140 steel plate is mainly used to make steam turbine fasteners,fising tolls and so on.