KAJIAN VARIASI VISKOSITAS PELUMAS PADA PROSES QUENCHING TERHADAP KEKERASAN DAN MIKROSTRUKTUR BAJA AISI 1045

Hardness testing on AISI 1045 steel to produce high wear resistance and hardness properties, using heat treatment process and in holding time and forwarded to the quenching process using variation of lubricant viscosity, resulting in different hardness rate. Maximum hardness was found in specimens immersed in SAE 20 medium with an average hardness value of 234.8162 VHN, whereas minimum hardness was present in specimens with SAE 140 media, with an average hardness value of 194,2618. Furthermore, in the microstructure testing of SAE 20 lubricants, the martensite phase was 65.4911% and the ferrite phase was 34.5088%, which was dominated by its martensite phase, while the specimens dipped in SAE 40 lubricant showed martensite phase of 47.1952% and ferrit of 52.8047%, and SAE, 90 has a martensite of 32.3786% and ferrit of 67.6213%, and SAE 140 has a martensite of 27.3372% and ferrit of 72.6627% which indicates that ferrit phase more dominates . It is found that the lubricant with viscosity SAE 20 has the best level of hardness attainment