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Teknologi Pembuatan Material Shot Blast untuk Mendukung Industri Pengecoran Logam Nasional Nurjaman, Fajar
Jurnal Teknik Mesin Vol 11, No 2 (2009): OCTOBER 2009
Publisher : Institute of Research and Community Outreach - Petra Christian University

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Abstract

Shot blast material is a supporting material in foundry which is used at surface finishing process of metal casting. Recently, there is no one of national industry that produce shot blast material, in consequence, the purpose of this research is to lessen the dependence of using shot blast material import by making a shot blast material which improve its hardness exceed the shot blast material import. This research use the raw material from scrap iron with the following composition: C (3.2%), Si (1.18%), Mn (6.1%), Cu (0.35%), Fe (88.7%). The scrap is melted in induction furnace untill melt (hot metal), then the hot metal (1200 oC) is tilted into a runner which is connected with pan crucible, which is consisted of 107 holes with diameter of each holes is 10 mm. Hot metal that is leave from the holes, is injected by pressurized water 1.1 atm with the velocity 0.8 m/s, untill obtained grains of shot blast material, then these grains goes into the water tank which it has temperature 40oC. From thermodynamic study, to avoid the happening of the explosion that is arising out because the effect of high temperature difference at injection process beetween water and hot metal, hence the comparison value beetween the mass of water and hot metal equal to 1:4.6. From this research is obtained shot blast material Ø0.8-3.2 mm with the metallography structure with martensite domination and dispersion of cementite and a little austenit. The hardness value of this material is 54.8 HRC, where this value is larger than shot blast material import (45-50 HRC). Abstract in Bahasa Indonesia: Material shot blast merupakan material pendukung pengecoran logam yang digunakan pada proses surface finishing benda cor logam. Saat ini belum ada satupun industri nasional yang memproduksi material shot blast, karena itu tujuan penelitian ini untuk mengurangi ketergantungan penggunaan material shot blast impor dengan membuat material shot blast yang nilai kekerasannya melebihi material shot blast impor. Penelitian ini menggunakan bahan baku scrap besi dengan komposisi: C (3,2%), Si (1,18%), Mn (6,1%), Cu (0,35%) Fe (88,7%). Scrap dilebur dalam tungku induksi hingga mencair (hot metal), lalu hot metal (1200oC) di tuang ke dalam runner yang terhubung dengan pan crucible yang terdiri dari 107 buah lubang berukuran Ø10 mm. Hot metal yang keluar dari lubang tersebut diinjeksi oleh air bertekanan 1,1 atm dengan kecepatan 0,8 m/s, hingga diperoleh butiran material shot blast, lalu butiran itu masuk ke dalam bak air bertemperatur 40oC. Dari kajian termodinamika, untuk menghindari terjadinya resiko ledakan yang timbul akibat diferensiasi temperatur yang tinggi saat proses injeksi, maka besarnya nilai perbandingan massa air dan hot metal sebesar 1:4,6. Dari penelitian ini diperoleh material shot blast berukuran Ø0,8-3.2 mm dengan struktur metalografi yang didominasi oleh struktur martensit dengan sebaran sementit dan sedikit austenit. Nilai kekerasan material ini adalah 54,8 HRC, dimana nilai ini melebihi nilai kekerasan material shot blast impor (45-50 HRC). Kata kunci: Shot blast, induction furnace, nozzle, hot metal, pengecoran logam.
APPLICATION OF HIGH ALLOY CAST STEEL MATERIAL ON THE GRINDING COMPONENT (HAMMER) IN HAMMER MILL MACHINE Nurjaman, Fajar; Sumardi, Slamet; Handoko, Anton Sapto
Widyariset Vol 14, No 3 (2011): Widyariset
Publisher : LIPI-Press

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Abstract

Hammer mill is one kind of machine that needs high durability, especially for grinding components such as hammers, which has a function to crush stone (mineral) in to fi  nely shaped (mesh 80). So these components should be made from materials which have some properties, such as high strength, toughness, and wear resistance. In his experiment, the hammers was made from high alloy cast steel, by using mangan, chrom, and copper as alloying materials. The chemical composition of these hammers are: (1) 3~5% Mn – 3~5% Cr – 3~5% Cu; (2) 4~6% Mn – 3~5% Cr – 7~9% Cu; (3) 3~5% Mn – 4~6% Cr – 7~9% Cu; (4) 3~5% Mn – 3~5% Cr – 10~12% Cu; (5) 5~7% Mn – 4~6% Cr – 14~16% Cu. Some of mechanical testing was given to these hammers, such as hardness testing, microstructure analysis testing, and also durability evaluation by using hammer mill machine with capacity 300 kg iron ore/hour. From durability evaluation, those hammers which are made from high alloy cast steel, with mangan, chrom, and copper as alloying material, showed a good result in wear rates by less than 0.4 mm2/kg iron ore. The lowest wear rates of this hammers is 0.14 mm2/kg iron ore, showed by hammers which had a composition 1.6%C – 3.2%Mn – 4.5% Cr – 3.2%Cu with 360 HBN in hardness value.
TEKNOLOGI PEMBUATAN SPIEGEL PIG IRON MENGGUNAKAN HOT BLAST CUPOLA FURNACE Nurjaman, Fajar
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 25, No 1 (2015)
Publisher : Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1524.468 KB) | DOI: 10.14203/risetgeotam2015.v25.138

Abstract

ABSTRAK Spiegel pig iron merupakan besi kasar (pig iron) mengandung 10-20% Mangan (Mn), yang dapat diperoleh dengan cara melebur bahan baku, berupa bijih mangan, reduktor dan flux. Spiegel pig iron dapat digunakan sebagai bahan paduan pada material baja, seperti plain steel carbon, low alloy steel, dan manganese steel. Dalam penelitian ini akan dipelajari proses pembuatan spiegel pig iron menggunakan tungku hot blast cupola. Spiegel pig iron terbuat dari pellet komposit, yang terdiri dari; bijih mangan kadar rendah (85,5%), batubara (12,5%) dan bentonit (2%). Pelet komposit tersebut dilebur ke dalam hot blast cupola dengan menggunakan bahan bakar berupa kokas. Batu kapur (CaCO3) juga ditambahkan ke dalam tungku tersebut sebagai flux (material pembentuk slag). Serangkaian pengujian dilakukan terhadap produk logam spiegel pig iron dan slag yang dihasilkan, meliputi uji komposisi (menggunakan Optical Electron Spectroscopy/ OES dan Emission Dispersive X-Ray/EDAX) serta analisis struktur mikro (menggunakan mikroskop optik). Dari hasil penelitian ini diperoleh material spiegel pig iron dengan komposisi sebagai berikut: 3,67 C - 1,92 Si - 21,26 Mn. Struktur mikro terdiri dari karbida (Fe,Mn)3C dalam matriks pearlit. Slag memiliki komposisi 20,1 Mn - 1,73 Fe - 52,19 SiO2 - 8 CaO, dengan nilai basisitas 0,2. Struktur mikro slag berbentuk batang (rod) memanjang.ABSTRACT Spiegel pig iron is a pig iron containing 10-20% Manganese (Mn). It is produced by smelting some raw materials, such as manganese ore, reductor, and flux. This material can be used as alloying element in some type of steels, such as plain steel carbon, low alloy steel, and manganese steel. The investigation of Spiegel pig iron making process in hot blast cupola has been conducted in this research. The spiegel pig iron was made from  pellets composite, consists of low grade manganese ore (85.5% wt); coal (12.5% wt); and bentonite (2% wt). The pellets composite were smelted with cokes, as a fuel in hot blast cupola. Limestone (CaCO3), as a flux (slag forming material), was also charged. Some of testing method was conducted to spiegel pig iron and slag, which includes; composition analysis (by using Optical Electron Spectroscopy/OES and Emission Dispersive X-Ray/EDAX); and micro structure analysis (by using optical microscopy). The spiegel pig iron containing 3.67 C - 1.92 Si - 21.26 Mn was resulted in this experiment. Its microstructure consists of carbide (Fe,Mn)3C inside pearlite matriks. The slag, containing 20.1 Mn - 1.73 Fe - 52.19 SiO2 - 8 CaO, had basicity 0.2. Its microstructure was in the form of a rod lamellae.
PEMBUATAN NPI (5-8% Ni) MENGGUNAKAN HOT BLAST CUPOLA FURNACE KAPASITAS 3 TON/HARI Nurjaman, Fajar; Shofi, Achmad; Astuti, Widi; Suharno, Bambang
Jurnal Teknologi Mineral dan Batubara Vol 14, No 1 (2018): Jurnal Teknologi Mineral dan Batubara Edisi Januari 2018
Publisher : Puslitbang tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (617.472 KB) | DOI: 10.30556/jtmb.Vol14.No1.2018.193

Abstract

Bijih besi nikel laterit merupakan batuan mineral dengan kandungan 10-40%Fe; 0,8-3,5%Ni; dan 1-2%Cr, yang merupakan bahan baku untuk pembuatan Nickel Pig Iron (NPI) yang selanjutnya dapat diolah menjadi besi-baja paduan mengandung Ni dan Cr. Dalam penelitian ini telah dilakukan pembuatan NPI menggunakan teknologi berinvestasi rendah, yaitu hot blast cupola furnace (tungku kupola udara panas) dengan kapasitas 3 ton NPI/hari. Proses aglomerasi bijih nikel laterit menjadi pellet komposit (Ø10-20 mm) terlebih dahulu dilakukan sebelum dilebur ke dalam hot blast cupola furnace. Komposisi (dalam %berat) pellet komposit adalah 85,5% bijih nikel laterit; 12,5% batubara; dan 2% bentonit. Dalam proses peleburan ditambahkan kokas (sebagai bahan bakar dan reduktor) dan batu kapur (sebagai flux) ke dalam tungku tersebut. Rasio penggunaan kokas terhadap pellet komposit adalah 0,4. Penambahan batu kapur (CaCO3) dilakukan untuk memperoleh kondisi basisitas slag 1,0. Aditif berupa MnO2 (39% Mn) juga ditambahkan ke dalam hot blast cupola furnace. Pada proses peleburan, kondisi temperatur udara panas (hot blast) adalah 250-300 ºC. Dari hasil penelitian diperoleh NPI dengan kandungan 5-8% Ni. Penambahan aditif MnO2 sebanyak 1% mampu menekan laju reduksi senyawa besi oksida sehingga mampu meningkatkan kandungan Ni dalam NPI.
RANCANG BANGUN TUNGKU BUSUR LISTRIK SATU FASE UNTUK PELEBURAN KONSENTRAT MANGAN DAN BESI MENJADI FEROMANGAN SUPRIYATNA, YAYAT I.; RISTIANA, RINA; NURJAMAN, FAJAR; SHOFI, ACHMAD
Jurnal Teknologi Mineral dan Batubara Vol 10, No 3 (2014): Jurnal Teknologi Mineral dan Batubara Edisi September 2014
Publisher : Puslitbang tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (811.225 KB) | DOI: 10.30556/jtmb.Vol10.No3.2014.732

Abstract

Telah dilakukan rancang bangun tungku busur listrik satu fase untuk melebur konsentrat mangan, konsentrat besi, dan sedikit skrep besi menjadi logam paduan feromangan berkapasitas 10 kg. Tungku dirancang dengan mempertimbangkan sistem geometri, elektrik dan sistem aktuator hidroliknya. Rancangan tungku berbentuk cawan silindris dengan diameter bagian dalam 15 cm dan tinggi selubung bagian dalamnya 22 cm. Suplai daya yang diperlukan sebesar 35 KVA. Energi yang dibutuhkan dalam proses peleburan sebesar 32,016 KJ. Dengan dimensi diameter elektroda grafit sekitar 2,7 cm, maka panas akan terjadi saat busur listrik berdekatan dengan bahan baku/konsentrat. Panas yang ditimbulkan mampu melebur konsentrat mangan, konsentrat besi dan skrep besi menjadi lelehan logam paduan feromangan. Ujicoba tungku tersebut menghasilkan komposisi produk logam paduan feromangan berkadar Mn ≥ 70% dan Fe = 14 - 16%. Oleh karena itu, model rancangan tungku busur listrik ini layak diperbesar skalanya dengan mempertimbangkan konstruksi geometrik, daya dan aktuator hidrolik yang digunakan.
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 | Full PDF (16.051 KB) | DOI: 10.14203/jti.v35i2.181

Abstract

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

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (570.606 KB) | DOI: 10.14203/metalurgi.v28i3.261

Abstract

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.
Pengaruh Temperatur Austenisasi terhadap Struktur Mikro dan Nilai Kekerasan Material 14%Cr-3%Ni-2%Mo-2%C untuk Aplikasi Bola Gerus Romaeni, Imaniar; Manurung, Posman; Nurjaman, Fajar
Jurnal Teori dan Aplikasi Fisika Vol 5, No 2 (2017): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (634.936 KB) | DOI: 10.23960/jtaf.v5i2.1381

Abstract

This study was conducted to determine the effect of heat treatment in the form of sub-critical, austenization, quenching and tempering the hardness values of the white cast iron material as consideration for testing wear resistance of local and foreign products as grinding balls. Samples was treated sub-critical at a temperature of 700°C with a hold time of 2 hours and continued with austenization temperature variation of 850, 950 and 1050°C with a hold time of each sample is 5 hours. The optimum hardness value was obtained at a temperature of 950°C austenization in the amount of 68.3 HRC and decreased at a temperature of 1050°C. It is because the solubility of carbon elements making up the matrix. Next will be tempering at a temperature of 250°C and holding time 2 hours hardness values decreased but the value of wear resistance is obtained even better ie grinding balls of 0.03 g/kg of product due to the combination of its constituent elements, namely chromium-molybdenum and nickel are high the presence of wear phenomena induced martensite.
THE EFFECT OF ADDITIVES AND REDUCTORS IN SELECTIVE REDUCTION PROCESS OF LATERITE NICKEL ORE Nurjaman, Fajar; Sa'adah, Anis; Shofi, Achmad; Apriyana, Wuri; Suharno, Bambang
Jurnal Sains Materi Indonesia Vol 20, No 1: OCTOBER 2018
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (257.505 KB) | DOI: 10.17146/jusami.2018.20.1.5404

Abstract

THE EFFECT OF ADDITIVES AND REDUCTORS IN SELECTIVE REDUCTION PROCESS OF LATERITE NICKEL ORE. Selective reduction of laterite nickel ore followed by magnetic separation was carried out to produce ferronickel products. The effect of adding additives and reductor types in the selective reduction process was studied in this study. Reductors used were anthracite coal and palm shell charcoal with variations of 5 to 15% by weight, while the additive used was sodium sulfate (Na2SO4). The reduction process was carried out at temperatures of 950 ºC, 1050 ºC and 1150 ºC for 60 minutes. The addition of 10% sodium sulfate additives by weight in the reduction process of laterite nickel ore produced higher concentrations of nickel as 6.09%, compared to no additives, i.e. 2.45%. The addition of reductors in the selective reduction process of laterite nickel ore shows that the higher the amount of reductors causes a decrease in the concentrate level of nickel. Furhtermore, the type of reductors used shows that the concentrate from the reduction result using anthracite coal reductor produces higher level of nickel and lower level of iron compared to the use of palm shell charcoal reductor.
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

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/metalurgi.v34i1.464

Abstract

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.