Effect of Molybdenum as an Alloying Element on the Strength of Grey Cast Iron

Grey cast iron’s thermal conductivity and mechanical properties depend on graphite flake morphology and length. Molybdenum is generally added to ferrous alloys to improve the mechanical properties as it forms carbides. However, molybdenum has two effects on the graphite flakes. A small quantity of Mo addition increases the thermal conductivity and decreases the tensile strength by increasing the length of the few graphite flakes. At the same time, higher molybdenum content leads to the formation of carbides and a decrement in graphite content, due to which thermal conductivity reduces and tensile strength increases. This work has verified five different weight percentages of the molybdenum on the tensile strength of the grey cast iron. Molybdenum addition resulted in a double peak effect on the tensile strength of the grey cast iron. Maximum tensile strength of 176.83 MPa was obtained, corresponding to a 0.59 weight percentage of molybdenum, followed by the next high strength of 164.74 MPa with a 0.02 weight percentage. Tensile strengths of 144.48, 146.43, and 145.19 MPa corresponded to 0.15, 0.29, and 0.74, respectively.