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The Effect of Manganese, Chromium and Boron into the Hardness and Microstructure of Steel Shot Nurjaman, Fajar
Teknologi Indonesia Vol 35, No 2 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i2.181

The objectives of this experiment were to investigate the effect of alloying elements, such as manganese, chromium, and boron, and also the effect of heat treatment into the hardness and microstructure of steel shot. Inthis experiment, a steel shot containing of 0.5?0.8% C was produced. The manufacture of steel shot was carried out by using the injection-pressurized water method. The raw materials, such as steel scrap and alloying elements were melted in an induction furnace. The round shape steel or steel shot with 0.5?3.2 mm in diameter was obtained by injecting the molten steel, which was fl owed from induction furnace into a distributor (pan crucible), by 1.1 atmosphere of pressurized water using a nozzle, and then the steel shot was splashed down into a tank containing water for cooling process. The dimension of pan crucible was in the form of cylinder tube with 300 mm in diameter and 130 mm in length, containing of 107 holes, with 10 mm in diameter for each hole. Some tests were conductedinto steel shot material, there were the hardness testing by using a Rockwell hardness tester, and the microstructure analysis by using an optical microscope. The addition of manganese, chromium, and boron into steel shot caused the hardness value of steel shot signifi cantly increased, 57 HRC for 3.6% Cr and 55 HRC for 2.3% Mn?1.8% Cr?2% B. The heat treatment process, by tempering at temperature 250oC for 5 minutes, produced fi nely martensite on its microstructure with 58 HRC (the hardness of as-manufactured steel shot was 55 HRC).

KARAKTERISTIK STRUKTUR MIKRO DAN SIFAT MEKANIK BESI TUANG PUTIH PADUAN KROM TINGGI HASIL THERMAL HARDENING UNTUK APLIKASI GRINDING BALL[Microstructure Characteristic and Mechanical Properties of Thermal Hardened of High Chromium White Cast Iron for Grinding Ball Application] Sofi, Achmad; Astuti, Widi; Nurjaman, Fajar
Metalurgi Vol 28, No 3 (2013): Metalurgi Vol.28 No.3 Desember 2013
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

KARAKTERISTIK STRUKTUR MIKRO DAN SIFAT MEKANIK BESI TUANG PUTIH PADUANKROM TINGGI HASIL THERMAL HARDENING UNTUK APLIKASI GRINDING BALL. ASTM A532Type II-A adalah jenis material besi tuang putih paduan krom tinggi (high chromium white cast iron), dengankandungan karbon 2,3% dan krom lebih dari 13,3%. Umumnya ASTM A532 Type II-A banyak digunakansebagai grinding ball. Pada studi penelitian ini, proses perlakuan panas berupa thermal hardening dilakukanterhadap material ASTM A532 Type II-A untuk meningkatkan nilai kekerasannya. Proses quenchingmenggunakan dua buah media quenching yang berbeda, yaitu oli dan udara paksa (udara ditiupkan secaralangsung dari fan), sedangkan proses tempering dilakukan pada temperatur yang bervariasi yaitu 250 °C, 300 °C,dan 350 °C. Hasil proses thermal hardening kemudian diuji keras, metalografi dengan OM (optical microscopy),SEM (scanning electron microscopy) dan XRD (X-ray diffraction). Harga kekerasan optimum dari besi tuangputih paduan krom tinggi (ASTM A532 Type II-A) adalah sebesar 723 BHN, yang dihasilkan dari prosesthermal hardening dengan media quenching oli pada temperatur tempering 300 °C. Tingginya harga kekerasanyang dihasilkan dari proses tersebut adalah akibat terbentuknya fasa martensit temper dan tersebarnya karbidakrom dalam jumlah besar (volume fraksi tinggi). AbstractASTM A532 Type II-A is a high chromium white cast iron with carbon content 2.3% and chromium morethan 13.3%. This material is widely used as a grinding ball. In this study, heat treatment process which isthermal hardened, was conducted to increase the hardness of this material. Quenching process used two kindof quench media, such as oil and forced air (which was blown directly from fan), while the tempering processwas conducted with various temperatures, 250 °C, 300 °C, and 350 °C. After thermal hardening process,material was characterized by hardness testing, metallography by OM (optical microscopy) and SEM(scanning electron microscopy), and XRD (X-ray diffraction). The optimum hardness value is 723 BHNresulted from thermal hardening process at 300 °C. Higher hardness value was obtained due to form oftempered martensite and numerous of chrom carbide disperse in this material.

PEMANFAATAN LIMBAH INDUSTRI BAJA: PELEBURAN MILL SCALE MENGGUNAKAN SUBMERGED ARC FURNACE Nurjaman, Fajar; Prilitasari, Nurbaity Marsas; Prasetyo, Arif Eko; Nugroho, Eko
Metalurgi Vol 34, No 1 (2019): Metalurgi Vol. 34 No. 1 April 2019
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Mill scale merupakan limbah/produk samping dari industri baja yang mengandung senyawa besi oksida hematite (Fe2O3), magnetite (Fe3O4) dan wustite (FeO). Telah dilakukan proses peleburan mill scale menjadi logam pig iron sebagai bahan baku alternatif untuk pembuatan material baja. Sebanyak 30 kg mill scale digerus hingga berukuran -40 mesh, kemudian dilakukan proses pencampuran dengan menambahkan batubara (reduktor internal) dan bentonite (perekat) sebanyak 2% berat untuk selanjutnya dilakukan proses aglomerasi menggunakan mesin briket. Briket komposit mill scale dilebur bersama dengan kokas (reduktor eksternal) dan batu kapur (material fluks) menggunakan submerged arc furnace. Pengaruh penambahan batubara dalam briket komposit, jumlah kokas dan batu kapur dalam proses peleburan mill scale telah dipelajari. Dari proses peleburan mill scale diperoleh kondisi optimum, yaitu konsumsi energi spesifik sebesar 3,64 kWH/kg produk, dengan menggunakan briket komposit mill scale dengan penambahan 0% batubara dan penambahan batu kapur sebanyak 3 kg (10% berat) serta kokas sebanyak 7 kg (stoikiometri). Basisitas optimum proses peleburan mill scale adalah 1,0. Produk logam pig iron hasil peleburan mill scale dapat dikembangkan lebih lanjut sebagai bahan baku pembuatan material besi tuang kelabu, putih dan mampu tempa.

PENGARUH PENAMBAHAN KROMIUM PADA Ni - HARD 2 TERHADAP SIFAT MEKANIK DAN STRUKTUR MIKRO Aritonang, Partogi A.F.; Ojahan, Tumpal; Nurjaman, Fajar
Jurnal Teknologi Bahan dan Barang Teknik Vol 12, No 1 (2022)
Publisher : Balai Besar Bahan dan Barang Teknik

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37209/jtbbt.v12i1.209

Pengaruh penambahan kromium pada material Ni-Hard 2 (kondisi as-cast) terhadap sifat kekerasan, impak, laju keausan, dan struktur mikro telah dipelajari dalam penelitian ini. Material Ni-Hard 2 paduan kromium dibuat dengan melebur scrap besi, ferrochrome dan ferronickel menggunakan tungku induksi frekuensi tinggi hingga temperatur 1450-1500°C. Selanjutnya logam cair tersebut dituang ke dalam cetakan pasir, hingga diperoleh sampel berukuran Ø20x100 mm. Nilai kekerasan tertinggi dan laju keausan optimum (terendah) diperoleh pada material Ni-Hard 2 dengan penambahan 12% kromium, yaitu sebesar 42,3 HRC dan 0,48 x 10-6 mm3/mm. Nilai impak optimum diperoleh pada material Ni-Hard 2 dengan penambahan 7% kromium, yaitu sebesar 54,8 J/cm². Hasil dari pengamatan foto struktur mikro material pada kondisi as-cast memiliki struktur fasa berupa austenit, ferit, dan karbida.

DAMPAK PENINGKATAN PANAS DAN JENIS REDUKTAN TERHADAP SAPROLIT: STUDI PENDAHULUAN Bahfie, Fathan; Manaf, Azwar; Astuti, Widi; Nurjaman, Fajar; Prasetyo, Erik; Susanti, Diah; Sipahutar, Wahyu Solafide
Indonesian Mining Journal Vol 27 No 1 (2024): Indonesian Mining Journal, April 2024
Publisher : Balai Besar Pengujian Mineral dan Batubara tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30556/imj.Vol27.No1.2024.1533

Indonesia significantly contributes to the global electric vehicle battery market due to its substantial medium- and low-grade nickel reserves. This study utilized saprolitic nickel ore from Halmahera, Maluku, Indonesia. However, the research on saprolite needs some improvements due to its complex mineral composition, which affected on the roasting process significantly. Therefore, a thorough understanding of the properties of laterite ores is critically important, particularly concerning laterite pre-reduction processes. The ore was finely sieved to a particle size of less than 100 mesh and then heated at temperatures of 250, 900, and 1150°C with the variation of reductant (anthracite and palm kernel charcoal). Extensive mineralogical analysis was conducted using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). The analysis of saprolite showed that it contains about 1.82% nickel, 30.47% iron, 10-20% magnesium, 4.86% aluminum, and 8.1% silicon by weight. Its mineral composition is mainly 53.1% goethite, 38.3% lizardite, and 8.7% quartz. The study found that goethite in saprolite was transformed into hematite around 250°C. At 900°C, the forsterite was crystallized, and at 1150°C, the ferronickel was formed. The transformation of lizardite is important as it affected on nickel diffusion within the iron matrix, which impacted on the material's properties. A thermal upgrading method with reductants like anthracite and palm kernel charcoal was used at lower temperatures to enhance the properties of saprolite. These findings provided valuable insights into saprolite's mineralogical composition and behavior, potentially offering improvements in various industrial processes and applications.

DAMPAK PENINGKATAN PANAS DAN JENIS REDUKTAN TERHADAP SAPROLIT: STUDI PENDAHULUAN Bahfie, Fathan; Manaf, Azwar; Astuti, Widi; Nurjaman, Fajar; Prasetyo, Erik; Susanti, Diah; Sipahutar, Wahyu Solafide
Indonesian Mining Journal Vol 27 No 1 (2024): Indonesian Mining Journal, April 2024
Publisher : Balai Besar Pengujian Mineral dan Batubara tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30556/imj.Vol27.No1.2024.1533

Indonesia significantly contributes to the global electric vehicle battery market due to its substantial medium- and low-grade nickel reserves. This study utilized saprolitic nickel ore from Halmahera, Maluku, Indonesia. However, the research on saprolite needs some improvements due to its complex mineral composition, which affected on the roasting process significantly. Therefore, a thorough understanding of the properties of laterite ores is critically important, particularly concerning laterite pre-reduction processes. The ore was finely sieved to a particle size of less than 100 mesh and then heated at temperatures of 250, 900, and 1150°C with the variation of reductant (anthracite and palm kernel charcoal). Extensive mineralogical analysis was conducted using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). The analysis of saprolite showed that it contains about 1.82% nickel, 30.47% iron, 10-20% magnesium, 4.86% aluminum, and 8.1% silicon by weight. Its mineral composition is mainly 53.1% goethite, 38.3% lizardite, and 8.7% quartz. The study found that goethite in saprolite was transformed into hematite around 250°C. At 900°C, the forsterite was crystallized, and at 1150°C, the ferronickel was formed. The transformation of lizardite is important as it affected on nickel diffusion within the iron matrix, which impacted on the material's properties. A thermal upgrading method with reductants like anthracite and palm kernel charcoal was used at lower temperatures to enhance the properties of saprolite. These findings provided valuable insights into saprolite's mineralogical composition and behavior, potentially offering improvements in various industrial processes and applications.

Analisis tekno ekonomi teknologi pengolahan bijih nikel laterit menjadi Nickel Pig Iron (NPI) menggunakan Hot Blast Cupola Furnace Herlina, Ulin; Nurjaman, Fajar; Handoko, Anton Sapto; Shofi, Achmad
Dinamika Teknik Mesin: Jurnal Keilmuan dan Terapan Teknik Mesin Vol 10, No 1 (2020): Dinamika Teknik Mesin: Jurnal Keilmuan dan Terapan Teknik Mesin
Publisher : Universitas Mataram

Processing technology on nickel laterite ore to becomeNickel Pig Iron (NPI) using Hot blast cupola furnace issuch technology developed to push up the growth ofprocessing industry iron/steel contains nickel inIndonesia. The need of this technology is more urgentlyalong with the enforcement of regulation no 4/2009 inmineral and coal mining law, which prohibits all industryto export raw mineral products without preliminaryprocess. For this reason, in this research, technoeconomicanalysis for designing nickel lateriteprocessing plant to become NPI using hot blast cupolafurnace was carried out. This research was conductedbased on several data processes taken from nickellaterite smelting using hot blast cupola furnace. Technoeconomic analysis showed processing nickel laterite oreto become NPI using 3 units of hot blast cupola furnacewith total capacity 9 ton/day at kabupaten SouthKonawe, Southeast Sulawesi province was feasible tobe carried out, whereas feasibility investment score wasfair enough. The net present value (NPV) was IDR11,278,271,245, and internal rate of return (IRR) was23.28% with a payback period (PBP) of 4 years and 10months.

Studi pengaruh kadar mangan dan temperatur austenisasi terhadap struktur mikro dan sifat mekanik baja mangan Bahfie, Fathan; Aleiya, Zakhrofa; Milandia, Anistasia; Nurjaman, Fajar
Dinamika Teknik Mesin: Jurnal Keilmuan dan Terapan Teknik Mesin Vol 10, No 1 (2020): Dinamika Teknik Mesin: Jurnal Keilmuan dan Terapan Teknik Mesin
Publisher : Universitas Mataram

High manganese steel or austenitic manganese steelcommonly are used in mining industries such as thecomponent in an excavator, hammer mill, crusher, andjaw crusher plates. Those components are the alloy caststeel with containing manganese (Mn) about 11-18%.The mechanical properties of austenitic manganesesteel are depending on the amount of manganese andcarbon. The austenitic steel has three dominantproperties, i.e. high hardness; good wear resistance, andhigh impact resistance. The objectives of this researchare investigating the effect of the composition ofmanganese and the austenitization temperature on themicrostructure and mechanical properties of austeniticmanganese steel. Each variation of manganesecomposition was 5.87%. 9.42% and 15.28%. It washeated at 950, 1000 and 1050oC for 60 minutes and thenquenched with water. The result showed that the highesthardness was 46 HRC where the composition ofmanganese and the austenitization temperature was5.87%. and 1050oC. The lowest hardness number was16.3 HRC where the content of manganese and thetemperature was 9.42%. and 1050oC. The results agreedwith the microstructure of the increase in carbides andthe composition of manganese increased too. For thewear resistance properties, the optimum one was 6.78 x10-6 mm3/m at the composition of manganese andtemperature of 5.87% and 1050oC.

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