Pengaruh Perubahan Waktu Penahanan pada Proses Hardening Menggunakan Pendingin Oli terhadap Kekerasan dan Struktur Mikro Baja AISI 1045

Abstract

AISI 1045 steel is a type of medium or medium carbon steel which has a carbon content of 0,4 – 0,5%. This study aims to determine the effect of holding time of AISI 1045 steel in heat treatment with oil-cooled hardening process on hardness value and microstructure.

AISI 1045 steel is heated at 850°C using 3 holding time variations, namely 20, 30 and 40 minutes, with SAE 40 oil cooling media. Hardness value testing is carried out using a Hardness Rockwell Tester.

From the test results on the raw material obtained a hardness value of 30 HRc, for a holding time of 20 minutes an average hardness value of 46,6 HRc was obtained, while a holding time of 30 minutes obtained an average hardness value of 48,6 HRc and at a holding time of 40 minutes obtained an average hardness value of 50,1 HRc.

The results of testing the hardness value and microstructure show that the longer the holding time, the more the hardness value will increase, for the results of the microstructure of AISI 1045 steel treated with holding time, it can be seen that more carbon is distributed, while the 40-minute holding time from the observation results shows a phase change in shape so that it can cause higher distortion potential, while the 30-minute holding time microstructure becomes more homogeneous and regular.