bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen Induced Cracking of API X52 and X60 Sour Service Steels Subjected to Pre-Strain under Prolonged H2S Exposure
Authors: Korda A.A. , Taufiq T. 
Published: September 2019

Abstract
The effect of plastic deformation on API X52 and X60 sour service steels on hydrogen induced cracking was studied. Plastic deformation was performed with a tensile pre-strain with the percentage variation of strain. The HIC test was carried out with a duration of 168 hours of hydrogen charging to investigate the cracking behavior. After hydrogen charging, the cross sections of both steels were observed to find out hydrogen cracks. Ultrasonic testing was carried out on the specimen surface to see the distribution of laminated cracks. The hydrogen crack surface was observed using SEM. The results showed that the values of CSR, CLR and CTR increased with increasing percentage of pre-strain. Ultrasonic testing showed that the area influenced by HIC increased with increasing percentage of pre-strain. The susceptibility of API X52SS and X60SS to HIC increases with increasing percent of pre-strain. API Steel X52SS has better HIC resistance than X60SS on high pre-strain.
Effect of Shielding Gas and Filler Metal to Microstructure of Dissimilar Welded Joint Between Austenitic Stainless Steel and Low Carbon Steel
Authors: Purnama Dewin , Oktadinata Herry 
Published: September 2019

Abstract
Welding of dissimilar metals involves different types of metals which have different chemical composition, mechanical and thermal properties. This paper presents a study on dissimilar metal weld between type 304 stainless steel and SS400 carbon steel. The steel plates were welded by using different filler metals (solid wire, flux-cored wire) and different shielding gases (100%CO2, 90%Ar+10%CO2). Then the weldments were observed by optical microscope, scanning electron microscope and EDX analysis. It seems that the weldments which were welded by using 100%CO2 shielding gas have significant amount of inclusions in weld metal compared to 90%Ar+10%CO2 shielding gas mixture. The EDX analysis shown the inclusions are oxides which consist of some elements (C, Si, Cr, Mn) with O. The weldment which was welded by using 90%Ar+10%CO2 shielding gas mixture and solid wire has much less inclusions in weld metal.
Effect of Applied Voltage and Coating Time on Nano Hydroxyapatite Coating on Titanium Alloy Ti6Al4V Using Electrophoretic Deposition for Orthopaedic Implant Application
Authors: Nuswantoro Nuzul Ficky , Budiman Ikhwal , Septiawarman Andre , Tjong Djong Hon , Manjas Menkher , Gunawarman  
Published: September 2019

AbstractNanoparticles of Hydroxyapatite (HA) were coated onto biocompatible titanium alloy, Ti6Al4V ELI using Electrophoretic Deposition (EPD) in order to improve its bioactivity. Electrophoretic Deposition (EPD) has been selected as the coating method because of the simplicity of the instrument, inexpensive cost, and ability to coat complicated products. This study, therefore, aims to investigate the effect of voltage and coating time of EPD process on increasing of implant mass as a parameter of deposition rate, coating thickness, and surface coverage of the HA on implant screw prototype products. Voltages were controlled in the range of 3, 5, and 7 volt and coating times were in the range of 3, 5, and 7 minutes. Surface morphology was examined using scanning electron microscopy (SEM). Coating thickness was measured by coating thickness gauges. While surface coverage was determined using ImageJ software. Based on the result, applied voltage and coating time affects the mass growth of samples and HA coating thickness in positive correlation. However, on the surface coverage, applied voltage and coating time reach the optimum value at 5 volt and 5 minutes. The best HA coating in which fulfilling the standard for orthopaedic implants was obtained at 5 volts for 5 minutes with mass growth is 0.00107 g, coating thickness are 79.13 µm, and surface coverage is 97.89%. HA coating thickness that produced in this research has fulfilled the desired coating thickness for orthopaedic implant application (50-100µm). SEM micrographs show that nano-HA is coated the alloy surface uniformly at these parameters. It can be concluded that these parameters can be applied to coat titanium Ti6Al4V ELI with HA for improving bioactivity in the orthopaedic application.
Effect of Addition Tahongai Leaf Extract (Kleinhovia hospita Linn.) As Organic Inhibitor on 1040 AISI Steel
Authors: Yunita Triana , Putri Kusuma Asih Wentika , Novita Sari Eli , Sulistijono  
Published: September 2019

Abstract
This research will study about corrosion inhibition by using tahongai leaf extract (Kleinhovia hospita Linn.) in a 3.5% NaCl environment. The inhibitor is extracted using maceration process from Tahongai leaf (Kleinhovia hospita Linn.). Testing of antioxidant activity using DPPH method gives result that antioxidant activity of tahongai leaf extract (Kleinhovia hospita Linn.) is strong antioxidant (96%) compared to vitamin C (98%), functional group test by FTIR method indicates that tahongai leaf extract (Kleinhovia hospita Linn.) contain flavonoid shown by O-H bond (3357.41 cm−1), double bond C=C (164 3.36 cm−1), C-H bond (2922.24 cm−1, 1460.69 cm−1, 1375.57 cm−1), Efficiency of inhibition reach 99.9825% for addition of inhibitor with concentration 200 ppm and duration of immersion 20 days. This inhibition behavior is also supported by polarization measurements where the lowest corrosion rate of 8.3x10−4 mm/year is obtained at the same concentration and immersion time.
Corrosion Behaviour of Collagen Coated and Uncoated Biomedical Titanium Alloy (TNTZ) Within Human Synovial Fluid
Authors: Fajri Hidayatul , Ariani Windy , Gunawarman  , Tjong Djong Hon , Manjas Menkher 
Published: September 2019

AbstractThe corrosion behavior of uncoated Ti-29Nb-13Ta-4.6Zr (TNTZ) and collagen-coated TNTZ within human synovial fluid + NaCl 0.9% solution was investigated using immersion test in order to know the effectivity of collagen to increase bioactivity and also reducing corrosion rate as a coating material. Collagen was selected as coating material because of the ability of adhesion cell and increasing bone healing process. The immersion test has been used as corrosion method due to its simplicity and inexpensive. The immersion time in this study was for 2, 4, and 6 weeks. Surface morphology of material was examined by scanning electron microscope (SEM). Corrosion rate was calculated by measuring degradation of coating mass during the corrosion process. While mechanical property (hardness) of material was measured by microhardness testing. The result of this study showed that collagen coating has reduced the corrosion rate of TNTZ in the human synovial fluid where the corrosion rate of the coated TNTZ is 0.00125 mmpy and the corrosion rate of uncoated one is 0.00262 mmpy after 6 weeks immersion. On the other hand, the hardness of coated TNTZ is higher than the uncoated one. It can be concluded that the collagen coating increases both corrosion resistant and mechanical properties of TNTZ.
Effect of Aluminum and Silicon Antioxidants Addition on Porosity, Cold Crushing Strength, Wear Resistance and Hydration Effect of Alumina Spinel Refractories
Authors: Fernando E.D. , Korda A.A. 
Published: September 2019

Abstract
Due to their high resistance and wear resistance, alumina spinel (MgAl2O4) are widely used for slide gate on ladle. The characteristics strongly depend on the formation of ceramic phases in the matrix. Addition of antioxidants is used to prevent the graphite oxidation, possibly leading to porosity increase. Currently, other problem appears as the consequences of climate change. The object of this research is to study the effect of antioxidants addition in temperature variations. The influence of Al and Si addition is investigated by means of XRD, SEM, TGA-DTA, apparent porosity, CCS, wear resistance and hydration resistance tests. It was found that lowest porosity, highest CCS and best wear resistance were reached by sample containing Al 5% in 1400°C, while best hydration resistance was reached by sample containing Si 5%.
The Influence of Mold Material on Cooling Curve, Solidification Parameters, and Micro-hardness of Al–6wt.%Si in Unidirectional Solidification
Authors: Masnur D , Suyitno  , Malau V 
Published: September 2019

Abstract
The influence of mold material on cooling curve, solidification parameters, and micro-hardness were investigated. Al–6wt.% Si in clay and stainless steel mold was directionally solidified using vertical Bridgman type furnace. The samples were heated up to 700°C at 1.9°C/s heat rate, held for 60 minutes, cooled, and withdrawn at 40 µm/s. The results show that the increasing of thermal conductivity by 72% affects cooling curve shape, solidification parameters, and micro-hardness. Furthermore, comparative evaluation of the exponent value of the function of micro-hardness to distance and micro-hardness to growth rate also have been made to proposed the range of exponent value for each mold material.
The Effect of Variation of Nano SiC Reinforcement Particle Addition to Mechanical Properties of Mg/Nano SiC Composite by Stir Casting Method
Authors: Syahrial A Z , Hannan N D 
Published: September 2019

Abstract
Composites are advanced material which is being developed that contains of two materials or more in order to improve the mechanical properties. Magnesium composite is a suitable material beside aluminium and its alloy to be applicated as vehicle body structure due to its lightweight and its low density. Thus, the vehicle body structure with lightweight and good mechanical properties can be achieved. In this research, magnesium composite is fabricated by mixing magnesium as composite matrix and nano SiC as reinforcement particle with the variation of the volume fraction 0.05 %vf, 0.10 %vf, 0.15 %vf, 0.20 %vf, and 0.25 %vf with stir casting as fabrication methods. To characterize the composite product, several testing were done, which were chemical composition characterization, metallographic observation, SEM-EDS characterization, XRD characterization, hardness testing, wear testing, and impact testing. The result of this research shows that with nano SiC addition as reinforcement particle will increase mechanical properties of magnesium composite. The best mechanical properties of magnesium composite is shown by the addition of 0.15 %vf nano SiC. The result shows the brinnel hardness number of this composition is 39 HB and 0.0052 mm3/m wear rate. Mechanical properties of magnesium composite are increased due to several strengthening mechanism such as grain size reduction and Orowan strengthening mechanism.
Relationship Between Heat Treatment And Mechanical Properties Of Al-Si-Mg Alloy
Authors: Namikawa Yuki , Sugio Kenjiro , Sasaki Gen , Tabata Junji , Fuyama Nobuyuki 
Published: September 2019

Abstract
The relationship between heat treatment and mechanical properties of Al-Si-Mg alloy was investigated. Solution treatment at 808K for 6 hours, preliminary aging at room temperature for 60 hours and artificial aging at 473K for 1 hours were conducted. Not preliminary aged samples were prepared for comparison. The strength improved and the elongation decreased with increasing the amount of Mg. This trend was seen both preliminary aged and not preliminary aged samples. However, preliminary aged samples showed relatively high tensile strength and elongation comparing with not preliminary aged samples. EPMA analysis revealed that the precipitation of Mg2Si in preliminary aged samples was larger than that of not preliminary aged samples, and which possibly contributed to the improvement of strength of the preliminary aged samples. Thermodynamic calculation showed that Mg2Si phase was not undissolved at the solution temperature, 808K, and these undissolved Mg2Si particles might influenced on mechanical properties negatively.
Effects Of Ionic Immersion Time On Optical Properties Of Cu2ZnSnS4(CZTS) Deposited by Successive Ionic Layer Adsorption And Reaction (SILAR)
Authors: Rukini Asywendi , Reza Alvian , Munir Badrul 
Published: September 2019

Abstract
Cu2ZnSnS4(CZTS) thin films fabricated by successive ionic layer adsorption and reaction (SILAR) method is a promising combination to actualize a low cost thin films Solar Cell (TFSC). Ionic exchange and rinsing time are critical point for ionic layer formation in SILAR method. The purpose of this study is to investigate the influence of cationic and anionic immersing time on the band gap energy of CZTS. Immersing time was varied into 10, 20, 30 and 40 seconds for both deposited and annealed samples, which annealing was conducted on 300°C for two hours. Deposited results showed a linear increase on band gap energy as cationic immersing time extended. Whereas, nonlinear increment with optimum band gap 1.35eV at 30 seconds immersion happened for anionic time variation samples. Annealed CZTS with cationic time variation also showed a linear increasing band gap. Meanwhile, annealed with anionic time variation showed a backward tendency of the deposited samples which the band gap decrease nonlinearly as anionic immersing time lengthened.
The Effect of Adding Synthesis Silica from Rice Husk as Cement Substitution for High Strength Concrete
Authors: Fajar Fatriansyah J , Dhaneswara D , Aida Khairunnisa S , Kusumawardhani D 
Published: September 2019

Abstract
The synthesis of silica from agricultural waste was conducted. The thermal decomposition was conducted at 700°C which yields white-brown silica powder. Acid mechano-chemical method was done to reduce the size particle of silica and homogenize the distribution particle. The variables used were the rotational speed of planetary ball-mill at 22 rpm and the addition of acid (HCl 1M). Under controlled burning, the highly reactive ash (silica products) that is produced can be used as a supplementary cementing material or in the production of high strength concrete (HSC). The samples were tested during its 28th day to know its compressive strength.
Failure Analysis of Superheater Boiler Tube SA 213 T12
Authors: Ardy Husaini , Bangun Deri Andika 
Published: September 2019

Abstract
Superheater tubes SA213 T12 (OD = 57 mm, WT = 6 mm) has been in service for 11 years in a supercritical coal fired boiler (315 MW). Tubes operating temperature are 430°C and pressure is 11 MPa. Failure occurred on tube no. 20, row 2. Three tubes specimens from the same row (failed tube, tube no. 3, and no. 4), were drawn for laboratory examinations. Vickers microhardnesses of failed and no. 3 tubes are the same (140 VHN), while tube no. 4 hardness is 170 VHN. These hardness values are much lower compared to the new tube (192 VHN). The lower hardness value of failed tube is due to complete decomposition of pearlite colonies in inner and outer side of failed tube to ferrite and spheroidized cementite. Failure of tube is characterized by thin lip rupture which indicated that the tube circumferential deformation occur gradually following spheroidization process. Failure by intergranular crack occurred along grain bondaries when the stress on the tube wall (hoop stress) exceeding material strength at service temperature. Tube no. 3 and 4 are partially spheroidized, mostly on the innerside. The severity of microstructure damage is related to the flow direction of flue gas, from tube no. 1 to no.2, no.3 and so on. Tube no. 1 was survived because it was protected by a front cover that will limit heat transfer from the flue gas. The previous failure analysis of similar boiler tube revealed that the hardness of the bulging tube is about 140 VHN which is the same as the hardness of the failed tube (no. 2) and no.3. Tube no. 3 is in the early stage of damage and shall be replaced because the hardness is much lower than 170 VHN. The effect of flue gas flow direction not only affects the hardness and microstructure but also deposit thickness. Deposit thickness in tube no. 2, 3, and 4 are 149, 123, and 100 µm respectively. Thicker deposit in tube no. 2 is also contributed to premature failure of this tube compared to the others. The local temperature of tube wall will be higher because thick deposit will reduce heat transfer between flue gas and steam inside the tube.
The Tensile Strength of Petung Bamboo Fiber Reinforced Epoxy Composites: The Effects of Alkali Treatment, Composites Manufacturing, and Water Absorption
Authors: Refiadi Gunawan , Syamsiar Yusi , Judawisastra Hermawan 
Published: September 2019

AbstractNatural fiber application due to its competitiveness attracted many research in green composites. However, the tensile properties of natural fiber composites might be influenced by several factors such as treatment of the fibers, manufacturing processes, and water absorption levels. In this research, we use petung bamboo fibers as natural fibers candidate for a good reinforcement in green composites. The study focused on the tensile property of bamboo fiber reinforced epoxy composites due to alkali treatment, manufacturing process, and water absorption. The composites were made with three variations: the fibers were varied without and with alkaline treatment (5% NaOH); manual lay-up method and hot press were applied as manufacturing variation; moisture content in the composites was varied in dry condition and after water absorption treatment. Tensile testing and Scanning Electron Microscope (SEM), were performed to improve tensile strength of composite and fiber-matrix interface quality. The alkali treatment has less effect to the tensile strength than of the volume fraction gain and the void content. Composite manufacturing by hot press has a significant effect to the improvement of tensile strength up to 37% compare to the hand lay-up method. Water absorption up to 8.8% had decreased the tensile strength of composites up to 29%. The alkali treatment on the bamboo fibers had effectively reduced water absorption into the composite as well as the tensile strength reduction.
Effect of Temperature on Corrosion behavior of Copper Silver Phosphorus Brazing Alloys in Chloride Containing Solution
Authors: Prajatelistia Ekavianty , Nurrochman Andrieanto , Kyehyun Cho 
Published: September 2019

Abstract
The groups of phosphorus-containing brazing alloys are the most favored filler metals used for joining copper and copper-base alloys. These brazing alloys are expected to have the optimum corrosion resistance during the application. However, failures arise at the braze joint generally caused and initiated by the corrosion of the brazing alloys when used at higher temperature than the room temperature. Since most studies of the phosphorus containing brazing alloys were performed at room temperature, this work has been extended to investigate the effect of various temperature on the corrosion behavior. Electrochemical measurements were carried out to observed the temperature effect with the temperature variation of 25, 40, 55 and 70 °C in 3.5% NaCl electrolyte. As the results, the copper-silver-phosphorus brazing alloy was undergone a selective dissolution by the attack of Cl-to the copper element. The temperature dependence of the alloy showed in agreement with the relationship of 2.3RT/F that have similar manner on pure copper tafel region. The schematic diagrams of the corrosion process were then proposed. This work could be helpful to understand in the field practically because the application temperature is usually higher than that of room temperature in general.
Study to Enhance Tantalum and Niobium Contents in Bangka Tin Slag by NaOH and HClO4 Leaching
Authors: Vincia Shiva F , Permana Sulaksana , Maksum Ahmad , Soedarsono Johny W , Widana Kurnia S , Trinopiawan Kurnia , Munir Badrul 
Published: September 2019

Abstract
Indonesia is rich in tin ores. Slags from processing of tin ores naturally contain substantial amount of valuable metals, in this case tiobium and tantalum. This research explores how niobium and tantalum contents in local Bangka tin slag can be enhanced using NaOH and HClO4leaching reagents. First, Bangka tin slag was NaOH-leached and, then, the slag underwent HClO4leaching. Before undergoing any processes, the contents of niobium and tantalum in Bangka tin slag were 0.47% and 0.23%, respectively. After passing two leaching processes, niobium and tantalum contents reached 1.28% and 0.79%, respectively.
Enrichment of Tantalum and Niobium Contents in Bangka Tin Slag by NaOH and H3PO4Leaching
Authors: Akli Hendri F , Permana Sulaksana , Maksum Ahmad , Soedarsono Johny W , Widana Kurnia S , Anggraini Mutia , Munir Badrul 
Published: September 2019

Abstract
This study explores how 0.23% tantalum and 0.47% niobium in tin slag from the Bangka-Belitung archipelago, Indonesia, are upgraded. To enrich the contents of both metals, this research involves 8M NaOH leaching followed by 0.5M, 1M, and 1.5M phosphoric acid. First, tin slag was roasted at 900°C for 2 hours. Then, the sample was NaOH-leached while H3PO4 was exploited to leach its residues. Next, each of the residues from the leaching processes was characterized by XRF while the filtrates characterization used AAS and ICP-OES. On the one hand, NaOH leaching has proven to decrease the contents of iron, calcium, titanium, and aluminum. On the other hand, 0.5 M H3PO4 leaching optimizes tantalum contents up to 0.85% while 1.0 M H3PO4 leaching maximizes niobium contents up to 1.45%.
Effects of Austempering Process to Mechanical Properties of Thin Wall Ductile Iron Connecting Rod.
Authors: Sulamet-Ariobimo R.D. , Fadlan M. , Kamili S. , Sukarnoto T. , Mujalis Y. , Oktaviano Y. 
Published: September 2019

AbstractAustempering process was carried out on thin wall ductile iron (TWDI) connecting rod produced by the design built in previous research. Austempering process was applied to improve the mechanical properties of the component, so it will be equal to forged steel. The aim of this work is to study the effects of austempering holding time to microstructure and mechanical properties of TWDI connecting rod. The process was applied to all connecting rods resulting from the vertical casting. The austenitising temperature was 960°C with 35 minutes holding time and the austempering temperature was 350°C with varied austempering holding time, that were 15, 30, 45 and 60 minutes. The process was held in fluidized bed furnace. Metallographic examination, tensile and compression stress-strain test were conducted directly to the connecting rod. The results showed that austempering process improved the mechanical properties of TWDI connecting rod and the result of the compression stress-strain test showed that the austempered TWDI connecting rod met its requirements.