Analysis of the Effect of Alloy Elements on the Hardness and Toughness of AISI 4340 Steel

Abstract

This study examines the effect of variations in alloying element content on the mechanical properties of AISI 4340 steel, namely hardness. The results show that the specimen with the highest nickel content (sample 4B) has an average hardness value of 80.88 HRC which is higher than other samples. Increasing the levels of nickel and molybdenum elements significantly increases the hardness and toughness of steel, where the highest hardness value is in 4B steel, namely 88.80 HRC, with Nickel alloy elements at 1.68% and molybdenum 0.40%. The hardness value of the steel resulting from this alloy treatment far exceeds the initial standard of 33.36 HRC, namely 88.80 HRC. proving that appropriate adjustment of the composition of alloying elements can improve the mechanical properties of steel. In addition, the optimal combination of alloying elements produces balanced mechanical properties that are very important for structural and automotive applications.