Pengaruh Variasi Waktu Tahan Solution Treatment Dan Aging Terhadap Perubahan Mikro Struktur Serta Kekerasan Copperized-AISI 1006

Rosalia, Olivia (2016) Pengaruh Variasi Waktu Tahan Solution Treatment Dan Aging Terhadap Perubahan Mikro Struktur Serta Kekerasan Copperized-AISI 1006. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Keberadaan tembaga dalam baja merupakan alasan precipitation hardening dilakukan karena penambahan tembaga di dalam baja dapat berperan sebagai grain refinement agent dan solid solution strengthening agent. Penelitian ini bertujuan untuk menganalisis pengaruh penambahan tembaga dan pengaruh waktu tahan solution treatment serta waktu tahan aging terhadap perubahan struktur mikro,dan perubahan nilai kekerasan copperized- AISI1006. Preparasi spesimen dilakukan dengan memotong spesimen dimensi 3x30x90 mm dan membersihkan permukaan spesimen dari karat dan pengotor, tahap penelitian terdiri dari metode copperizing yaitu dengan memanaskan baja pada temperature pre-heat 900°C dan copperized-AISI 1006 pada temperature sekitar 1083°C dengan immerse time yaitu 5 menit dilanjutkan pendinginan normalizing kemudian dilakukansolution heat treatment dengan variasi waktu tahan yaitu 30 dan 60 menit pada temperatur 900oC lalu diquenching. Setelah itu dilakukan aging dengan variasi waktu tahan yaitu 30,60 dan 90 menit pada temperatur 450oC dengan pendinginan normalizing. Tahap akhir adalah tahap identifikasi yang mana serangkaian pengujian spesimen dilakukan, adapun pengujian-pengujian tersebut antara lain: uji komposisi unsur menggunakan alat Optical Emission Spectroscopy (OES), uji perubahan struktur mikro dengan menggunakan alat mikroskop optik, uji kekerasan dengan menggunakan alat uji kekerasan mikro vickers serta uji karakterisasi material menggunakan alat SEM/EDX dan XRD. Dari hasil pengamatan makro memperlihatkan adanya lapisan tembaga dan oksida di permukaan substrat, hasil pengujian struktur mikro terbentuk struktur dominan matriks α-ferit dengan fasa kedua berupa partikel Fe-Cu pada batas butir serta lamanya waktu tahan pada solution treatment dan waktu tahan aging menyebabkan naiknya luasan daerah batas butir. Hasil pengujian OES memperlihatkan kenaikan kadar tembaga dalam baja sebesar 0,0905% dan mapping tembaga menunjukkan bahwa cluster tembaga memiliki kecenderungan berkumpul di batas butir. Pengujian XRD menunjukkan adanya pergeseran puncak Fe yang mengindikasikan Cu masuk kedalam Fe dan terbentuk fasa baru yaitu Cu0,003Fe0,997. Sedangkan pengujian kekerasan memperlihatkan penurunan nilai kekerasan setelah dilakukan proses aging. =================================================================================== The existence of copper in the steel was one of the reason why this precipitation hardening was perfomed. The addition of copper inside the steel has a role as grain refinement agent and solid solution hardening agent. This research aimed to analyse the effect of cooper addition and theeffect of holding time of solution treatment and holding time of aging in the copperizing process of AISI 1006 towards the transformation of microstructure, and the alteration of AISI 1006 hardness number. The preparation of specimen wasperfomed by cutting the specimen into 3 x 30 x 90 mm and cleaning the surface of the specimen from rust and impurities. The step of this research consisted of copperizing method by pre heating the steel until 900o C and heating the copperized AISI 1006 until 1083o C with immerse time, 5 minutes which followed by cooling normalizing and then solution het treatment was perfomed with variation of holding time 30 minutes and 60 minutes at 900o C and followed by quenching. After that, aging was performed with holding time variation 30, 60 and 90 minutes at 450o C and followed by cooling normalizing. The final step was identification of specimens which perfomed by elemental composition test using Optical Emission Spectroscopy (OES), transformation of microstructure test using optical microscope, hardness test using micro Vickers and material characterization using SEM/EDX and XRD. The result of macro observation showed that there were copper and oxide layer on the surface of the substrate and from microstructure examination showed there were formed the dominant structure was α-ferit matrices with the second phases in the form of granular bainite which consisted of irregular ferrite and Fe-Cu particle in the grain boundary, also the duration of holding time in solution treatment and aging caused the expansion of grain boundary area. The result of OES examination showed the increasing of copper content inside the steel as much as 0,0905% and copper mapping showed that copper cluster had a trend to accumulate in the grain boundary. XRD examination showed the shifting of Fe peak which indicated the diffusion of Cu inside the Fe and new phase, Cu0,003Fe0,997was formed. While hardness test’s result exhibited the decreasing hardness number after aging process was perfomed.

Item Type: Thesis (Undergraduate)
Additional Information: RSMt 620.182 Ros p
Uncontrolled Keywords: AISI 1006; aging; copperized; precipitation hardening; solution treatment; waktu tahan; copperized; holding time
Subjects: T Technology > TN Mining engineering. Metallurgy
Divisions: Faculty of Industrial Technology > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User: Mrs Anis Wulandari
Date Deposited: 16 Jun 2017 07:23
Last Modified: 27 Dec 2018 06:52
URI: http://repository.its.ac.id/id/eprint/41720

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