PENGARUH PERLAKUAN THERMAL CYCLING PADA COLD ROLLED AISI 316L DENGAN DERAJAT REDUKSI BERBEDA-BEDA TERHADAP STRUKTUR MIKRO DAN KEKERASAN

Rosalina, Amanda (2020) PENGARUH PERLAKUAN THERMAL CYCLING PADA COLD ROLLED AISI 316L DENGAN DERAJAT REDUKSI BERBEDA-BEDA TERHADAP STRUKTUR MIKRO DAN KEKERASAN. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kecelakaan kerja dan kecelakaan lalu lintas merupakan salah satu penyebab utama terjadinya kasus patah tulang. Salah satu tindakan yang dilakukan oleh dokter dalam mengobati patah tulang adalah dengan melakukan pemasangan implan tulang. Salah satu jenis material implan tulang yang umum digunakan adalah austenitic stainless steel 316L yang memiliki sifat mekanik tinggi sesuai standar internasional ASTM F138 dan memiliki biokompatibilitas yang tinggi. Beberapa produsen di Indonesia telah memproduksi implan lokal 316L dengan metode investment casting. Walaupun secara standar ASTM telah memenuhi persyaratan, namun secara sifat mekanik, produk lokal masih dibawah produk impor dari Eropa atau Amerika. Agar implan lokal mampu bersaing dengan produk impor maka dilakukan proses modifikasi struktur mikro agar butiran investment casting yang berukuran besar yaitu sekitar 83.17 µm dapat dirubah menjadi butiran halus dibawah 10 µm melalui mekanisme rekristalisasi. Mekanisme rekristalisasi ini dapat dipicu dengan melakukan thermal cycling pada 316L yang telah diberikan perlakuan cold-rolling. Derajat reduksi cold rolling yang berbeda-beda akan memberikan jumlah stored strain energy yang berbeda sehingga mempengaruhi dislocation density yang ada di dalam material. Mekanisme rekristalisasi saat thermal cycling sangat bergantung dari dislocation density ini. Hasil penelitian menunjukkan bahwa pada stainless steel 316L setelah diberi perlakuan thermal cycling pada 900°C selama 35 detik dengan 4 kali siklus dengan derajat reduksi cold rolling 52%, 60%, 69%, 80% dan 90% menunjukkan bahwa pada derajat reduksi 80% dan 90% terjadi rekristalisasi total dari butiran secara merata pada semua bagian. Ukuran rata-rata butiran mengecil menjadi 3.26 µm, dan 2.87 µm dan kekerasan rata-rata meningkat dari 159 HV menjadi 257 HV dan 267 HV. Pada kondisi derajat reduksi yang lain, ditemukan bahwa rekristalisasi belum terjadi pada keseluruhan material. Kekerasan yang diperoleh juga lebih rendah dibanding pada kondisi 80% dan 90% dengan ukuran butiran rata-rata yang lebih besar dan perbedaan antar butiran minimum dan maksimum yang lebih lebar.=============================== ================================================================================================================== Accidents during work and in the road are one of the main causes of bone fractures. An orthopedic surgeon usually install bone implant to support damaged bone. One of the bone implant that is widely used is austenitic stainless steel 316L. This material had high mechanical properties as dictated by international standard ASTM F138 and proven to exhibit biocompatibility. Several manufacturers in Indonesia have been succesfully produced 316L implants using investment casting method. Even though the mechanical properties of local implant product had met ASTM standards requirements, it was still lower as compared to imported implant from Europe or US. In order to compete with imported products, local implant 316L from investment casting was modified to reduce their coarse grain size of about 83.17 µm in average to become finer grain of under 10 µm through recrystallization mechanism. This recrystallization mechanism on 316L can be triggered by thermal cycling after 316L was subjected to cold-rolling treatment. Different degrees of cold rolling reduction will give different amounts of stored strain energy which will affect the amount of dislocation density in the material. The recrystallization mechanism during thermal cycling was aided by the availability of density dislocation. After cold rolled 316L with thickness reduction degrees of 52%, 60%, 69%, 80% and 90% were given thermal cycling treatment at 900°C for 35 seconds with 4 cycles, it was found that homogenous full recyrstallization was confirmed on 80% and 90% reduction degrees samples. The average grain size of 80 and 90% reduction degree samples decreased to 3.26 µm and 2.87 µm respectively while the average hardness increased to 257 HV2 and 267 HV respectively from 159 HV measured for investment casting product. Conversely, only partial recrystallization was observed in other degree of reduction samples. The obtained hardness also lower than 80% and 90% reduciton degree. Larger average grain size and wider minimum and maximum grain differences was measured on these samples.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Cold rolling, implan stainless steel 316L, investment casting, thermal cycling, Cold rolling, implant stainless steel 316L, investment casting, thermal cycling.
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TA Engineering (General). Civil engineering (General) > TA418.42 Hardness properties and tests
T Technology > TJ Mechanical engineering and machinery
T Technology > TN Mining engineering. Metallurgy > TN690 Metallography. Physical metallurgy
T Technology > TN Mining engineering. Metallurgy > TN752.I5 Steel--Heat treatment
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Amanda Rosalina
Date Deposited: 21 Aug 2020 03:12
Last Modified: 21 Aug 2020 03:12
URI: http://repository.its.ac.id/id/eprint/79239

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