Pengaruh Temperatur Annealing Solution Treatment dengan Cryogenic Quenching pada Implan AISI 316L terhadap Kekerasan dan Struktur Mikro

Departemen Kesehatan RI pada tahun 2013 mencatat sekitar 13 juta orang mengalami kejadian fraktur atau patah tulang di Indonesia. Patah tulang merupakan suatu kondisi dimana terjadi diskontinuitas tulang sehingga diperlukan tindakan medis untuk mengembalikan tulang yang patah ke posisi semula dan mencegah tulang bergeser. Salah satu tindakan yang sering dilakukan adalah pemasangan implan tulang dari bahan logam seperti stainless steel AISI 316L. Melihat tingginya kebutuhan implan logam AISI 316L, maka PT. Pelopor Teknologi Implantindo memproduksi implan lokal stainless steel AISI 316L menggunakan teknologi investment casting. Namun secara umum, produk yang dihasilkan masih memiliki kualitas di bawah implan produk impor karena perbedaan metode pembuatannya. Oleh karena itu, penelitian ini dilakukan untuk meningkatkan kualitas dari produk lokal dengan meningkatkan sifat mekaniknya. Material implan stainless steel AISI 316L hasil investment casting di annealing solution treatment pada temperatur 1050o C, 1100o C, 1150o C dan 1200o C selama 2 jam. Kemudian didinginkan super cepat (cryogenic quenching) dengan liquid nitrogen yang memiliki suhu -177 C. Pengaruh temperatur annealing solution treatment terhadap hasil cryogenic quenching diamati dengan melihat nilai kekerasan material dan pengujian metalografi. Hasil penelitian menunjukkan bahwa nilai kekerasan mengalami kenaikan pada seluruh material yang diberi perlakuan cryogenic quenching jika dibanding material hasil investment casting. Pada annealing solution treatment di temperatur 1150o C, diperoleh nilai kekerasan yang paling tinggi yaitu 177,6 HV dibanding 144,5 HV pada material investment casting. Pada temperatur itu juga terjadi pengecilan rata-rata ukuran butiran menjadi 129,73 µm dibandingkan dengan rata-rata ukuran butiran hasil investment casting yaitu 216,98 µm. Dengan kenaikan kekerasan dan pengecilan ukuran butir, dapat dikatakan bahwa proses annealing solution treatment dengan cryogenic quenching dapat memperbaiki sifat mekanik AISI 316L. ================================================================================================ The Indonesian Ministry of Health in 2013 reported that around 13 million Indonesians suffered bone fractures from different cases. Bone fracture is a condition where the bone discontinuity occurs and installation of medical device such as implant become necessary in order to return the bone into its original condition and keep the bone into their shape. Stainless steel AISI 316L is one of the impant material that is commonly used. Unfortunately, the majority of implant material in Indonesia were imported, thus PT. Pelopor Teknologi Implantindo develop local implant based on AISI 316L stainless steel implants using investment casting technology with local raw materials. Nevertheless, there is still a challenge since the local products is considered still have lower quality than the premium grade imported implants. Therefore, the aim of this research is to improve the quality of local implant using cryogenic quenching to improve their mechanical properties. 316L stainless steel implant material from investment casting was treated by heating up to annealing solution treatment temperature for 2 hours and then cryogenic quenched in liquid nitrogen. In this study, different temperature of 1050o C, 1100o C, 1150o C dan 1200o C are investigated and the effect of the annealing solution treatment temperature is observed through hardness value and microstructures change.. This research show that in general, the hardness of AISI 316L stainless steel material treated with cryogenic quenching is increased as compared with investment casting material. It is found that annealing temperature of 1150o C followed by cryogenic quenching resulted in the highest rise of hardness of 177,6 HV as compared with investment casting product of 144,5 HV hardness. This result also in correspondence with the grain size as the treated product have lower average size of 129,73 µm in comparison to 216,98 µm from investment casting products. Cryogenic quenching with annealing solution treatment improve mechanical properties by increasing the hardness and reduce grain size