Effect of Quenching and Tempering Processes on the Microstructure, Hardness, and Wear Resistance of AISI 1045 Steel
Imam Basori1, Akhid Septoaji1, Agung Premono1, Juliawati Alias2

1Department of Mechanical Engineering, Universitas Negeri Jakarta, Indonesia
2Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, Malaysia

Abstract

Steel is one of the most widely used metallic alloys in industries such as automotive, mining, construction, and manufacturing due to its favorable mechanical properties, including high hardness, wear resistance, and the ability to tailor its properties through heat treatment processes. This study investigates the effect of quenching and tempering treatments with different holding times on the microstructure, hardness, and wear behavior of AISI 1045 steel. The quenching process was conducted at 850 C using water as the cooling medium with holding times of 30 and 60 min, followed by tempering treatments with holding times of 30 and 60 min.
The results revealed that the quenching treatment produced a martensitic microstructure characterized by fine and densely distributed needle like morphology. Increasing the holding time during quenching resulted in a more homogeneous and compact martensitic structure. Subsequent tempering transformed the martensite into tempered martensite, while longer tempering times promoted carbon diffusion and the formation of fine carbide precipitates. Hardness testing showed a significant increase in hardness after quenching, from approximately 205 HVN in the untreated material to 603 HVN and 669 HVN for holding times of 30 and 60 min, respectively. Following tempering, the hardness values decreased to a range of 536 to 575 HVN due to the reduction in martensitic brittleness.
Wear test results indicated that the wear rate decreased after quenching. The untreated material exhibited a wear rate of 5.51, which decreased to 4.47 and 3.17 for quenching holding times of 30 and 60 min, respectively. However, the tempering process slightly increased the wear rate, although the increase was not significant. Overall, the results demonstrate that variations in holding time during quenching and tempering significantly influence the microstructure, hardness, and wear resistance of AISI 1045 steel.

Keywords: AISI 1045 steel, heat treatment, quenching, tempering, martensite

Topic: Material Physics