Studi Eksperimental Pengaruh Variasi Temperatur Dan Holding Time Perlakuan Panas Austempering Terhadap Struktur Mikro, Impact Strength Serta Kekerasan FCD 600

Austempered Ductile Iron (ADI) merupakan material yang memiliki keunggulan pada kombinasi sifat mekanik, massa jenis dan machinability. ADI diperoleh dari ductile iron yang diberi perlakuan panas austempering. Struktur mikro serta sifat mekanik pada ADI ditentukan oleh variasi temperatur austempering dan holding time. Pada perlakuan panas austempering, mula-mula material dipanaskan sampai temperatur 900oC kemudian ditahan selama 1 jam. lalu material dipindahkan ke dapur salt bath untuk proses austempering pada temperatur 275oC,325oC dan 400oC dengan holding time masing-masing selama 30 menit, 60 menit dan 120 menit Dari hasil pengujian didapatkan bahwa presentase karbon pada material melebihi standar yang telah ditentukan. Dengan perlakuan panas austempering, material FCD 600 mengalami perubahan struktur mikro dan sifat mekanik. Material FCD 600 yang telah mengalami perlakuan panas austempering memiliki struktur matriks penyusun bainitic ferrite. Nilai impact strength dan kekerasan mengalami kenaikan dibandingkan dengan material as cast. Seiring kenaikan temperatur austempering dan holding time akan menyebabkan kenaikan nilai impact strength serta penurunan nilai kekerasan pada material setelah perlakuan. ================================================================================================== Austempered Ductile Iron (ADI) is material that has advantages such as combination of mechanical properties, density and machinability. ADI obtained from ductile iron that had been austempering heat-treated. It microstructure and mechanical properties is determined by variations of austempering temperature and holding time. In the Austempering Heat Treatment of the Ductile Iron FCD 600, the material initially warmed up to the austenisation temperature, which is 900° Celsius, the warming up is then held for an hour. Afterwards, the material is then moved into the salt bath furnace for getting the austempering process in 275°, 325°, and 400° Celsius with the holding time for 30, 60, and 120 minutes respectively. From the test result showed that the percentage of carbon in the material exceed from JIS G5502. FCD 600 that has undergone austempering heat-treated has a matrix structure with a bainitic ferrite. Impact strength and hardness value of austempered material increased in comparison with the as cast material. As the austempering temperature and holding time rise will cause impact strength increasing and hardness in material impairment after treatment