@thesis{thesis,
		author={  Dr. Ir. Ngafwan and Ardansyah  Brian Jodi},
		title ={Pengaruh Quenching Dilanjutkan Austempering 200°C Dengan Variasi Waktu Penahanan 50s, 100s, 150s, 200s, 300s Terhadap Perubahan Struktur Mikro Dan Kekerasan Baja AISI 4140},
		year={2022},
		url={http://eprints.ums.ac.id/100124/},
		abstract={This study discusses the transformation of the morphology of the microstructure and the hardness of the austenitizing and tempering processes on AISI 4140 steel. The microstructure morphology test used a microscope type X1005 TTEPPL ASTM E3 and the Rockwell hardness test ISO / FDIS 6508 HRC ATSM E18. This research was carried out in ATZcr780?C-Qwater- AT750?C- DT200?C-HT(50s, 100s, 150s, 200s and 300s)-Qwater. Analysis of the number of grains, grain area, microstructure test and rockwell hardness test. After the austenitizing process, there is an increase in the number of granules and the area of granules for the raw material. In the AT750?C-DT200?C- HT(50s, 100s, 150s, 200s and 300s)-Qwater processes. There was a decrease in the number of grains and the total area with different removal times. In the hardness test T750?C- DT200?C- HT(50s,100s,150s,200s and 300s) there was a change in the hardness value of HT 50s = 59.8 HRA, HT 100s = 60.8 HRA, HT 150s = 59.8 HRA, HT 200s = 59.7 HRA and HT 300s = 60.3 HRA.
Keywords:  aisi  4140  steel,  austenitizing,  austempering,  holding  time, quenching, microstructure, hardness}
		}