Pengaruh Substitusi Ion Mn dan Ion Co Serta Ion Ti pada Pembentukan Fasa dan Sifat Magnetik Barium Hexaferrite BaFe9(MnCo)1,5Ti1,5O19 Disintesis Melalui Rute Metallurgi Serbuk

ABSTRACT Barium hexaferrite dengan struktur molekul BaFe12O19 dikenal dengan baik sebagai magnet permanen yang memiliki sifat mekanik dan banyak menyita perhatian peneliti beberapa tahun lalu hingga sekarang. Pada penelitian ini serbuk hexaferrite dihasilkan melalui mekanisme konvensional menggunakan metoda metallurgi serbuk. Struktur kristal serbuk hexaferrite dianalisis menggunakan Difraksi X dengan sumber Co(kα) pada panjang gelombang 1.78896 ˚A sedangkan sifat magnetik material diuji dengan Permeagraph dengan medan magnet luar 1.5 Tesla. Hasil kalkulasi parameter kisi pada magnet konvensional (BaFe12O19) diperoleh hasil a = b = 5,894 Å dan c = 23,210Å, sedangkan pada fasa tersubstitusi memiliki perubahan pada kisaran a = b = 5,893 Å – 5,899Å dengan nilai c pada kisaran 23,328Å sampai dengan 23.346Å. Dengan adanya substitusi parsial ion Fe +3 dengan Ion Mn+2 , ion Co+2 dan ion Ti +4 terjadi penurunan sifat magnetik terutama pada koersivitas magnetik pada dari 125 kA/m (konvensional) menjadi dibawah 5 kA/m pada material tersubstitusi. Kata kunci: magnet ferrite, mikrostruktur, koersivitas, remanen, saturasi magnetik ABSTRAK Barium ferrite with hexagonal molecular BaFe12O19 is well-known for its high performance permanent magnetic and good mechanical properties and attracted attention of researchers for a long time. The hexaferrite powders were produced according to a conventional ceramic process with powder metallurgy method. Moreover, the powders were analyzed by X-ray diffraction, to detect the presence of secondary phases. The magnetic properties of the samples were measured at room temperature using Permeagraph with a maximum applied field of 1.5 T. The calculation of the lattice parameter on conventional magnets (BaFe12O19) results a = b = 5,894 Å and c = 23,210 Å, while the substituted phase has a range value of a = b between 5,893 Å to 5,899 Å, and c lattice parameter value is in the range of 23,328 ˚A to 23,346 Å. With the partial substitution of Fe +3 ions by Mn+2 ions, ion Co+2 and Ti +4 ion magnetic properties decrease primarily on the magnetic coercivity from 125 kA / m (conventional) to ~ 5 kA /m in the substituted materials. Keywords: ferrite magnetic, microstructure, coersivity, remanent, magnetic saturatio

Evaluasi Besar Butir Terhadap Sifat Mekanis Cuzn70/30 Setelah Mengalami Deformasi Melalui Canai Dingin

The research was conducted because of the many industries that use CuZn 70/30 as a raw material in industrialization. CuZn 70/30 was studied to obtain the strong mechanical properties of brass. Research CuZn 70/30 was evaluated using a process of heating of about 6150 ± 50C and then held for 90 minutes. The next process is the process of cold rolling by using a variety of reduction and then tested by using a Vickers hardness testing, tensile testing, observation of the microstructure. The result of this research is a fine microstructure (below 10 μm), hardness (HV 211.67). Tensile test also conducted to get how much resistance CuZn 70/30 to resist the pull. The cold rolling process causing the decrease the mechanical properties and also increase the plastic properties of the brass

Failure Analysis of ICDP Work Roll of Hot Strip Mill: Case Study of Shell-Core Interface Spalling

The failure of the roll during the rolling process causes cobble to lose production time for several hours. Investigations include visual inspection, lltrasonic test, chemical analysis, metallography, and hardness measurement. Stand finishing F1-F4 uses High Chrome (HCr) material type, while Stand F5-F6 uses ICDP material type. Spalling work roll occurs on stand F5 with Roll Top position. Roll was chipped between shell and core with an exfoliation percentage of 30% of the roll surface area. Visually, the chipped part looks smooth and even. Thus no typical sign of fatigue or brittle failure was observed. The chemical composition of the roll conforms to the standard. Roll surface hardness that does not experience spalling follows the standard. The metallography analysis found micro-cracks in the spalled samples and inclusions in the form of scale in the shell-core interface. Based on the study, it can be concluded that the spalling roll is caused by poor bonding of the shell and core on the roll

Pengaruh Kecepatan Dan Temperatur Uji Tarik Terhadap Sifat Mekanik Baja S48c

Influence of Strain Rate and Temperature of Hot Tension Testing on Mechanical Properties of Medium Carbon Steel S48C. The characterization of S48C by hot tension testing was done to understanding the influence of temperature and strain rate for S48C flow stress, that close relationship with its forge ability. The hot tension testing was performed on temperatures and strain rates variation (T 850, 900, 950 0C and έ 0,01;1 s-1). The result of hot tension testing showed that increasing temperature decreases ultimate tensile strength (UTS) and flow stress of S48C. The higher decreasing of UTS is on 950 0C about 85% from room temperature condition, while the higher decreasing of flow stress has occurred on 950 0C about 31 % compare to conditions of temperature 850 0C, strain 0,23 & strain rate (έ)1 second-1 and about 27% compare to the same conditions but έ= 0,01 second-1 . For increasing strain rate from 0,01 to 1second-1 on the temperature range (850-950 0C) increases UTS about 33 - 50 % and flow stress about 46-53%

Evaluation of Microstructure High Chrome Austenitic Stainless-Steel grade 253MA after Creep Test at Temperature of 700°C

High Chrome Austenitic Stainless-Steel grade 253 MA is a material that widely used for high temperature. This is due the fact this material has excellent mechanical properties and creep resistance. However, changes in microstructure can occur in long-term use, which will affect the creep resistance (shortened service life of the material). The microstructure of High Chrome Austenitic Stainless-Steel 253 MA creep test specimens was investigated. Creep testing at a temperature of 700 °C with a loading of 150 MPa was carried out. The cold rolling process with 53% reduction in thickness was applied followed by annealing at 900°C, 1000°C, and 1100°C for 3600s to obtain different grain size. Grain size after annealing and after creep test was measured to see the effect of annealing temperature on the grain size of tested steel and to see its effect on creep resistance based on the creep test conducted. Grain size and morphology of the phase after creep test were observed by scanning electron microscope and optical microscop

SIFAT BALISTIK METAL MATRIX COMPOSITE DENGAN WOVEN METODE SATIN TWILLED WEAVE

Material Komposit terdiri dari dua atau lebih material yang berbeda menjadi satu material, bertujuan untuk meningkatkan sifat mekanik dari setiap material yang dimilikinya. Komponen komposit terdiri dari matrix dan reinforcing. Matrix digunakan material Al-Si, dengan reinforcing berupa fiber stainless steel wire rope, berdiameter 6 mm. Metode penelitian dengan melakukan anyaman (woven) metode Satin Twilled Weave, casting, machining, pengujian tekuk dan sifat balistik menggunakan senapan otomatis . Hasil uji tekuk pada kondisi patah, dengan jarak tumpuan 140 mm, diameter penekan 80 mm,sudut lengkung 180o dengan woven metode Satin Twilled Weave gaya maksimum 6,75 kN .Pada uji komposisi kimia bahan matrix menunjukkan kandungan Silikon (Si) sebesar 10,533 %. Untuk uji balistik, pada jarak 5 m menggunakan senapan otomatis peluru caliber 9 mm MU1TJ, material tidak tertembus peluru.Kata kunci: matrix, reinforcing,woven,caliber

Failure Analysis on Tube Arm Cylinder Hydraulic Excavator

The Failure on tube rod arm cylinder hydraulic excavator caused to lose production and processing time on mining site. Investigation included visual inspection, chemical analysis, metallography analyze, and microhardness test. Tube material used high silicon material type while the standard used ST52 carbon steel type. The tube was broken and crack to several pieces. The chemical composition of the tube has different in sulfur and silicon content. From hardness test with micro hardness method, sample tube broken has lower hardness compared to standard hardness. Metallography analysis obtained the phase of tube has same phase with standard which is ferrite and pearlite phase but has different grain size. Based on this study, it can be resumed failure on tube is because impurities and different specification on raw material.   &nbsp

Risk Indentification on Superheater Pipeline Boiler of 600 MW Power Plants Using a Risk Based Inspection (RBI) Method

Steam power plants are the most efficient type of power generation and can make a significant contribution to the demand for electricity resources. Steam power plants, in general, utilize energy derived from seawater to be process into steam in boilers so that often many pipe failures have occurred due to thinning due to corrosion caused by inappropriate water quality in small units and difficult to detect continuously. In general, inspection planning related to pipe thinning in steam power plants shows a minimal trend compared to inspections in the oil & gas industry. Moreover, it has no basic policy as to how inspection intervals and piping methods will be carry out. In this study, it carried out with the aim of conducting a risk assessment of boiler pipe failure so that it can provide a more optimal overview of the inspection plan. Analysis using Risk Based Inspection (RBI) will be used as a research reference to create the most effective and efficient inspection system as to minimize the impact and expenses cost in pipeline maintenance. After RBI assessment, the inspection plan for superheater pipeline on boiler line will be held every 2 years

PENGARUH KECEPATAN DAN TEMPERATUR UJI TARIK TERHADAP SIFAT MEKANIK BAJA S48C

Influence of Strain Rate and Temperature of Hot Tension Testing on Mechanical Properties of Medium Carbon Steel S48C. The characterization of S48C by hot tension testing was done to understanding the influence of temperature and strain rate for S48C flow stress, that close relationship with its forge ability. The hot tension testing was performed on temperatures and strain rates variation (T 850, 900, 950 0C and έ 0,01;1 s-1). The result of hot tension testing showed that increasing temperature decreases ultimate tensile strength (UTS) and flow stress of S48C. The higher decreasing of UTS is on 950 0C about 85% from room temperature condition, while the higher decreasing of flow stress has occurred on 950 0C about 31 % compare to conditions of temperature 850 0C, strain 0,23 & strain rate (έ)1 second-1 and about 27% compare to the same conditions but έ= 0,01 second-1 . For increasing strain rate from 0,01 to 1second-1 on the temperature range (850-950 0C) increases UTS about 33 - 50 % and flow stress about 46-53%.Keywords : forgeability, flowstress, temperature, strain rate, hot tensile testin

Pengaruh Proses Rolling Terhadap Struktur Mikro Dan Sifat Mekanis Pada Kuningan Setelah Diproses Ecap

Brass material widely used in industry because it has the advantage of being a metal that resists corrosion, has high ductility, good toughness and easy on the form. This study was conducted to determine the effect of rolling process on mechanical properties and microstructure of metal brass after ECAP process on brass (CuZn) 70/30. The initial step is to make the specimens with a diameter of 10 mm and height 80 mm has been done annealing 600 ° C with a hold time of 90 minutes. Then a ECAP 3-pass process and cold rolling process. To determine the mechanical properties of tensile test specimens and hardness test) and metallographic observations to determine the microstructure. The results after the execution of the research note that the specimen after passing through annealing process, ECAP and rolling have a higher hardness. Prior to treatment the specimen hardness value is 78 VHN and after treatment to 252 VHN hardness value. Metallographic observations of known properties of brass increasingly refined microstructure and grain boundary between micro become increasingly tight