Assessment of Nonhomogeneous Structures in Steel Contents in Terms of Fatigue Resistance Using Analytical Hierarchy Process

Fatigue resistance of steel containing non-metallic inclusions (NMIs) varies widely, depending on many criteria; therefore, finding the most compromised types of NMIs is a sober objective that may significantly reduce severe dam - age and premature failure in many applications, such as bearings, gears, transmission shafts, etc. The multiple criteria decision-making methodologies have been used in this study to assess the more effective NMI types using the ana - lytical hierarchy process by expert choice software. The five most common types of non-metallic inclusions selected are oxides, sulfides, carbides, silicates, and nitrides, based on different criteria: size, shape, distribution, mechanical properties, and quantity. The results showed that the oxide NMIs are the optimum type relative to the other four options regarding the fatigue resistance of about 35%, probably due to their spherical shape and small size. The most dominant criterion is mechanical properties, which have an effective percentage of 34.6% among the other criteria. It means that the reduction of other types rather than oxide NMIs probably enhances the fatigue resistance of the steel.