Abstract

Grey Cast Iron is a material that has good castability. Grey Cast iron have flakes graphite with ferrite and pearlite as matrix. FC 250 included in lamellar graphite cast iron with 250 N/mm2 minimum tensile strength. FC 250 with no alloying elements have a good vibration resistance, but have a poor hardness and tensile strength. This material is commonly applied in the otomotive industry such as in discbrake. The addition of alloying elements to FC 250 materials could increase the strength and hardness of the materials.Molybdenum as alloying elements in cast iron is known as ferrite stabilizer, pearlite refiner and for promoting the bainite microstructures. This research aims to analize the effect of Molybdenum element on the microstructure and mechanical properties On FC250. In this research Molybdenum is added with 5 variations to FC 250 i.e. 0%, 0,35%, 0,6%, 0,72, and 0,88%. Molybdenum added to the ladle before the tapping process.To analyze the effect of addition Molybdenum on the microstructure and mechanical properties on the FC 250 some testing was done such a tensile testing, hardness testing, microstructure testing, SEM testing, and composition testing. With 0,6% Molybdenum addition on the FC 250 material generate the optimum increase in the value of tensile and hardness. 0,6% Molybdenum addition increase the value of tensile strength from 271,5 N/mm2 on 0% Mo to 394 N/mm2 and increase the value of hardness from 191,1 HBS on 0% Mo to 245,6 HBS.

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