Evaluation of Aluminum Effect on the Microstructural changes, Mechanical properties and Fatigue life of Hadfield hypereutectoid Steel

In this study, the effect of aluminum alloying element on the microstructural changes, mechanical properties and fatigue life of Hadfield steel was investigated. For this purpose, 2 blocks castings were prepared from Hadfield steel (without Al and with 1.68 wt% Al addition) by using coreless induction furnace. After the casting, all the blocks were austenitized in 1100°C for 2 hours and immediately quenched in the pure water. In the next step, uniaxial tensile test, bending fatigue test and hardness test by vickers method were conducted on specimens. Microstructure evaluation was conducted by optical metallography and the fractured surfaces were observed by scanning electron microscopy. As a result, it was found that the sample containing 1.68 wt% Al had more hardness and greater yield strength but tensile strength, flexibility and fatigue life of lesser compared to sample without Al addition. So, scanning electron microscopy images indicated the occurrence of ductile fracture in tensile test for both samples and was increased fatigue crack growth in the fatigue test due to the addition of aluminum to chemical composition of Hadfield steel.