Pengaruh Variasi Kandungan Magnesium (Mg) dalam Proses Pembuatan Besi Cor Nodular terhadap Kekuatan dan Kekakuan Puntir

Nodular cast iron is one type of cast iron whose graphite is round. Magnesium (Mg) is the material most often used by the casting industry as a graphite forming material because it is more profitable than other materials. This study aims to determine the effect of magnesium (Mg) content in nodular cast iron to microstructure, torsional strength and stiffness of cast iron. The study was used FCD as the starting material which was then smelted in the melting furnace. The process of forming round graphite cast iron is carried out by using an open ladel system. Variations of 50 grams, 100 grams, 150 grams and 200 grams of FeSiMg was placed under a 15 kg capacity ladel just before the molten iron is poured into the ladel. The results showed that the increasing percentage of magnesium (Mg) produced the graphite granules tended to be smaller and uniform, and increased in pearlite area and reduced ferrite area, so that in torsional testing, strength values (Torsional Yield Strength and Modulus of Rupture) and stiffness value (Modulus of Shear Elasticity) have increased. The largest value of Torsional Yield Strength, Modulus of Rupture, and stiffness value from Modulus of Shear Elasticity occur in specimen 5 (0.0351% Mg) and the smallest value in specimen 1 raw material FCD (0.0296% Mg)