Jurnal Rekayasa Mesin

ANALISIS SURFACE HARDNESS ALUMINUM 6061 HASIL GAS NITRIDING DENGAN VARIASI HOLDING TIME

Tjuk Oerbandono — Fri, 15 Dec 2023 00:00:00 +0000

The nitriding coating process is widely applied in the industry. Gas nitriding is a technique used to improve the mechanical properties of a metal. This study aims to determine the influence of holding time variations on surface hardness and diffusion depth in aluminum alloy 6061 (Al-Mg-Si) that undergoes gas nitriding. The independent variable used in this study was holding time, namely, initial specimen (without holding time treatment), and specimens that experienced holding ranging from 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours. The cooling medium used after gas nitriding was air. The highest surface hardness value was obtained in aluminum alloy 6061 specimens without holding time treatment, namely with a hardness value of 141 VHN while the lowest surface hardness value was produced by the specimen with a holding time of 5 hours. The lowest surface hardness value was 55.4 VHN. Based on the results of the EDAX composition test known that the specimen of aluminum alloy 6061 with a holding time of 5 hours diffused nitrogen element of 1.57% and oxygen element of 5.27%.

THE EFFECT OF INFILL PATTERN AND DENSITY PARAMETERS ON TENSILE STRENGTH OF POLYMER MATERIALS IN 3D PRINTING

Sally Cahyati, Reky Amanda Putra — Fri, 15 Dec 2023 00:00:00 +0000

One of the references for selecting materials in designing a machine component is its mechanical property which is tensile strength. However, the current tensile strength from the materials used in 3D printing products has not been standardized due to many parameters in the design and process that affect them. The selection of correct design and process parameters may result in the proper mechanical properties and minimize the time and amount of materials used during the printing process. The parameters expected to affect the mechanical properties are density and infill pattern. This study was conducted to observe how far the effect of them on the mechanical properties of 3D printing product's tensile strength. The specimen standard of tensile strength used was ASTM D638, while the tested infill pattern was Grid, Triangles, and Tri-Hexagon patterns, with the percentage of total infill density of 20%, 40%, and 60%. PLA (Polylactic Acid) was chosen as the material used in this study. The 3D print machine operated was 3D Print MakerGear M2 with the tensile testing machine of HTE Hounsfield. The results of this study concluded that the percentage of infill density 20%, 40%, and 60% with different infill patterns had different tensile strengths. The specimen with a Tri-Hexagon infill pattern and 60% density had the biggest tensile strength value, followed by the Triangles infill pattern and the smallest one was the Grid pattern with 20% density.

PEMODELAN SISTEM DINAMIK DAN IMPLEMENTASI SIMULINK PENGENDALIAN KESTABILAN UNMANNED AERIAL VEHICLE MULTIROTOR HEXACOPTER CARGO

Steven Wiliam Soputra, Sheila Tobing, Seno Sahisnu Rawikara — Fri, 15 Dec 2023 00:00:00 +0000

The rapid growth of Unmanned Aerial Vehicle (UAV) technology, or drone, has shown its popularity and has been significantly applied to various purposes today. Nevertheless, with all the sophistication of drones, many related topics are still attractive, especially when a drone is designed to carry out a cargo mission. Thus, in this research, the dynamic model of a Hexacopter drone to deliver goods belongs to PT Aero Terra Scan is being developed. This dynamic modeling aims to further the drone's development by modeling it in 2 cases: no-payload and with a payload of 5 kg cases. The dynamic model of this Hexacopter is based on flight dynamics, a field of science studied in Aeronautical Engineering, and is implemented using Simulink. Through the results of this research, several conclusions have been withdrawn: (1) The drone's unstable nature characteristic inherently, even though it is analyzed from the initial hover condition. Thus, the drone and its system as a whole can never be separated with the feedback control that made it can maneuver adequately. (2) Several technical parameters of this Hexacopter, including the geometry, mass, the moment of inertia, until the estimation of motor throttle is required to achieve its hover conditions, both in the no-payload case and with-payload of 5 kg case. (3) The Hexacopter basic dynamic system model is based on the flight dynamics until its motion system control tuning through root locus map analysis using Simulink.

DINAMIKA DAN NYALA API PEMBAKARAN DROPLET CAMPURAN METIL LAURAT – METIL OLEAT

Lilis Yuliati, Nurkholis Hamidi , Muhamad Luthfi Lazuardi — Fri, 15 Dec 2023 00:00:00 +0000

This research intended to investigate the dynamics and flame of the droplet combustion of methyl laurate - methyl oleate blended. Methyl oleate is an unsaturated FAME with a relatively long carbon chain, frequently found as the dominant component in various biodiesel. Meanwhile, methyl laurate is a saturated FAME with a shorter carbon chain, which is the main component in coconut oil biodiesel. The methyl oleate content in the droplets was varied by 0, 20, 40, 60, 80, and 100%. Visual observations and temperature measurements were conducted on the combustion of suspended droplets with a diameter of 1.24 mm. The droplet is supported by a thermocouple junction with a wire diameter of 0.1 mm. The experimental results show that increasing of the methyl oleate content increase the ignition delay time, burning time, thermal expansion of droplets as well as fluctuations in droplet diameter and combustion temperature. Ignition delay time has a much greater value than burning time. This parameter should be suppressed to obtain more complete combustion and cleaner exhaust emissions, especially in internal compression engine applications where the time available for the combustion process is very short. This can be obtained by increasing the percentage of methyl laurate in biodiesel.

OPTIMASI MULTIOBJEKTIF PARAMETER PROSES 3D PRINTER JENIS FUSED DEPOSITION MODELLING MENGGUNAKAN GREY RELATIONAL ANALYSIS-TAGUCHI

Fri, 15 Dec 2023 00:00:00 +0000

The development of fused deposition modelling (FDM) 3D printer models is increasing where the applications can be found in several aspects such as rapid prototyping, functionally components, and parts for assembly process. These conditions required excellent printing quality. One of the factors that affect the printing quality was process parameter setting. There are several parameters process that are used in 3D printing. Hence, the use of these parameters that recommended by manufacturer often give the average results, not the best results. The recent study purposes are to gain optimal setting that give accuracy in the dimension and suitable surface condition. There are 12 factors with 3 different levels. The study used Taguchi method L-27 and grey relational analysis (GRA) to determine the most efficient combinations that can fulfill multi-objective. The results showed that to acquire the accuracy and total dimension, the following combination are used; LH0,075mm, LW0,45mm, IPLines, WT0,8mm, PT205C, FR85%, RD6,5mm, RS30mm/s, PS30mm/s, OWS15mm/s2, PA10mm/s2, and PJ10mm/s where wall thickness (WT); flow rate (FR); and retraction distance (RD) used as 3 essential factors that can influence the respond of the machine. The best surface roughness gathered with the combination as follow; LH0,075mm, LW0,35mm, IPGrid, WT0,8mm, PT200C, FR95%, RD2mm, RS30mm/s, PS70mm/s, OWS25mm/s, PA3000mm/s2, dan PJ30mm/s where the layer height (LH) was the essential factor that affect the machine respond. The accuracy of the dimension and the most optimum surface roughness can be acquired by the following combinations: LH0,075mm, LW0,35mm, IPGrid, WT0,8mm, PT205C, FR95%, RD4,5mm, RS30mm/s, PS70 m/s, OWS15 mm/s, PA3000 mm/s2, dan PJ10mm/s.

CITRONELLA OIL AS BIOADDITIVES ON SI ENGINE PERFORMANCE CHARACTERISTICS

Fri, 15 Dec 2023 00:00:00 +0000

Current dynamics of world energy supply have driven various innovations by the industry as well as research communities. Fossil fuels, although experiencing a declining interest due to sustainability issues, remain undeniably crucial since they are nearly irreplaceable in some sectors including electricity generation, it is necessary to continuously establish efforts to improve efficiency of those kinds of fuel. In this work, the authors evaluate the potential of locally sourced essential oils, namely citronella, as a fuel additive in a vision of raising the fuel economy of gasoline RON 90. Citronella oil was selected based on a positive hypothesis deduced from its chemical properties, as mentioned in multiple published works. Tests were made on a generator-set powered by gasoline engine using the mixture of RON 90 and citronella oil of various concentrations as the fuels. In addition, a commercial synthetic additive was also tested alongside the essential oil to provide a comparative figure. Meanwhile other investigators suggest a favorable effect of essential oils, our results show that citronella oil additions lead to higher fuel consumption at the same power level. A similar negative effect was also demonstrated by the synthetic additive. The only sector showing positive results is in terms of exhaust temperature where experiments with citronella additives create lower exhaust temperature as compared to pure gasoline and synthetic additives. However, rooms for innovation remain open by exploring other variables such as higher additive concentrations or combining different kinds of essential oils.

SURFACE QUALITY AND CORROSION RESISTANCE OF 316L STAINLESS STEEL ELECTROPOLISHED USING PHOSPHORIC – SULFURIC ACIDS

Hudiyo Firmanto, Budhyantoro Arief — Fri, 15 Dec 2023 00:00:00 +0000

Electropolishing is an electrochemical surface finishing technique. It is commonly applied to equipment that requires a gleaming finish. This surface property is frequently required in 316L stainless steel (SS) medical implants. Electropolishing removes a thin layer from the metal's surface through electrochemical processes. This results in a very clean, smooth, and bright metal surface. The process parameters, such as electrolyte solution, electrical current, and electropolishing time, influence surface roughness and glossiness. The dissolution of metallic ions during the process may also affect the corrosion resistance of the treated material in addition to producing a shiny surface. This study investigated the surface glossiness, surface roughness, and corrosion of electropolished 316L SS. Electropolishing experiments on 316 SS were carried out using various H₃PO₄ (50%) and H₂SO₄ (32%) electrolyte solution compositions. The influences of electrolyte solution composition, electric current, and electropolishing time were studied. The results showed that increasing the H₂SO₄ content of the mixture and electropolishing the 316L SS for a longer period of time improved the surface roughness and glossiness. Under 10 Amp electric currents, the best surface glossiness was discovered. A corrosion test revealed that the electropolishing produced a Cr and Ni-rich layer that improved the corrosion resistance of the samples.

DETEKSI CACAT BANTALAN GELINDING BERBASIS ALGORITMA DECISION TREES DAN PARAMETER STATISTIK

Berli Paripurna Kamiel, Fauzan Anjarico, Sudarisman Sudarisman — Fri, 15 Dec 2023 00:00:00 +0000

Rolling bearings are a common machine element found in rotary machines. The components in the rolling bearing such as the inner race, outer race, rolling element, and cage are the parts that are often damaged. Traditionally spectrum analysis is used to diagnose bearing defects. However, spectrum analysis is not effectively applied to bearings with early defects because the vibration signal generated is dominated by frequency components from other machine elements, so the frequency of bearing defects cannot be observed. This study proposes an alternative method of detecting bearing defects based on vibration signals using machine learning with a decision tree algorithm. This method is more effective than the spectrum analysis method because machine learning is based on feature extraction and pattern recognition of vibration signal data, therefore, providing classification results directly without further analysis. Vibration signals were recorded using an accelerometer mounted on a bearing housing on a test rig. Nine-time domain statistical parameters and six frequency domain statistical parameters were extracted from the vibration signal and then used as input for decision trees. The results show that the decision trees algorithm gives an accuracy of 94.4% for classifying three rolling bearing conditions using the input of 6 selected frequency domain statistical parameters.

PENGARUH LIQUID SUCTION HEAT EXCHANGER TERHADAP KINERJA SISTEM PENDINGIN PADA MESIN PORTABLE CHILLER

Fajar Budi Sulistiono, Ramon Trisno — Fri, 15 Dec 2023 00:00:00 +0000

When the Covid-19 pandemic occured, most of the industries and public facilities were not used properly, but the cooling machines was still used, resulting in large consumption of power and electrical energy. Along with high energy consumption where the availability of energy is running low, savings are needed. As an alternative so that the cooling machine can save energy is to use the subcooling method, namely the addition of a liquid suction heat exchanger on a spiral portable chiller with 29 spirals. Furthermore, the refrigerant used in the portable chiller is R407c. This study aims to determine the effect and effectiveness of Liquid Suction Heat Exchanger on a portable chiller. The results obtained are the coefficient of performance on the non-Liquid Suction Heat Exchanger portable chiller is 4,699 with a cooling capacity of 6,668 kW and compressor performance of 1,419 kW while the portable chiller with the addition of Liquid Suction Heat Exchanger, the Coefficient Of Performance obtained is 5,197 with a cooling capacity of 6,719 kW and compressor performance of 1,219 kW. From the calculation above, the use of a liquid suction heat exchanger in a portable chiller can increase the cooling capacity by 1,97 %.

SIMULATION-BASED ASSESSMENT KINERJA TERMAL PADA CONCENTRIC TUBE HEAT EXCHANGER

Fri, 15 Dec 2023 00:00:00 +0000

The double-pipe heat exchanger is one of the most popular heat exchanger devices. In this study, the concentric tube heat exchanger as the double pipe heat exchanger device was simulated with ANSYS code FLUENT. The simulation was done by based on the Reynolds number variation from 400010.000 using the method of co-current and counter flow. The hydrodynamic and thermal simulation results agree with the empirical correlation of the Pethukov and Dittus-Bolter equations, respectively. The friction factors of the water base fluid and nanofluid f TiO2/water f (0.1 vol.%) do not result in a significant difference in the turbulent flow regime for both co-current and counter flow. The thermal performance of TiO2/water (0.1% vol) nanofluid as indicated by the value of the heat transfer coefficient results in an increase of 6.9% for counter low flow and 6.0% for co-current flow. Meanwhile, the direction of fluid flow in the heat exchanger does not have a significant effect on its thermal performance.

PENGARUH VARIASI KECEPATAN PUTAR DAN DIAMETER PIN TOOLS TERHADAP KUAT GESER DAN STRUKTUR MAKRO SAMBUNGAN FRICTION STIR WELDING DISSIMILAR HIGH DENSITY POLYETHYLENE-POLYPROPYLENE

Totok Suwanda, Nur Ardiyansyah — Fri, 15 Dec 2023 00:00:00 +0000

The purpose of this study is to find out the effect of pin tool turn speed and pin tool diameter on strong shear and macro structure on the friction stir welding dissimilar high-density polyethylene and polypropylene sheets. Variations in welding process parameters used in this study were: rotary speed of 980, 1560, 2360 rpm, and pin tool diameter of 4 and 5 mm. The shape of the cylinder pin, the feeding speed of 11 mm/min, and the plunge depth of 7.8 mm were maintained constant. The results showed that the highest shear strength value was obtained on the connection with a rotary speed of 1560 rpm and a pin tool diameter of 5 mm 4.8 N / mm2 or 23.71% of the tensile strength of raw material high density polyethylene. Observations of macro structures show that the pin tool diameter 5 mm has only slight defects in the stir zone.

DESAIN KONSEP PURWARUPA MESIN INJECTION MOLDING TIPE VERTIKAL UNTUK DAUR ULANG LIMBAH PLASTIK SKALA RUMAH TANGGA

Sufiyanto Sufiyanto, Waridin Niam, Marfizal Marfizal, Myson Aziz — Fri, 15 Dec 2023 00:00:00 +0000

Plastic waste is the main cause of environmental pollution. It is necessary to research the design of the Injection Molding machine to process plastic waste. This study describes the design concept of a vertical type Injection Molding machine prototype by considering the factors to be utilized by small-scale plastic recycling businesses. The design stage starts from the identification of component requirements to the design of 3D drawings. The results of this study obtained a prototype design of a Vertical Injection Molding Machine. The embodiment of the design is not only determined directly by the design team and the manufacturing team, but is obtained from customer requests described in the technical specifications. At the concept design stage, there are 5 sub-functions and each function has 3 to 4 options. From the combination of these sub-functions and options, 3 assembly sketches were obtained so that 3 alternative design concepts were obtained. From the results of the concept assessment, design concept C was chosen from several alternative concepts.

IMO-COMPLIANT ANALYSIS OF THE LARGE ANGLE STABILITY OF CHEMICAL TANKERS DURING THE LOADING AND UNLOADING LIQUID CAUSTIC SODA

Ahmad Firdhaus, Mulyatno Imam Pujo, Muhammad Luqman Hakim, Wangi Nimas Ayu Sekar — Fri, 15 Dec 2023 00:00:00 +0000

MT. Sinar Masela 8831 DWT is a ship transporting oil and chemicals certified by IMO Chemical Class 2,3. According to Chapter B, SOLAS CHAPTER VII, regarding water safety, loading and unloading oil and chemicals is categorized as dangerous due to water damage and pollution. Various studies are needed to expedite the loading and unloading process to reduce damage and pollution in the waters. One of these studies is regarding the stability of ships in accordance with IMO criteria. The study was conducted to determine the ship stability on the MT. Sinar Masela is in the loading-unloading process. This study applies eight conditions with seven-compartment tanks on the ship using software to analyze the stability calculation when the loading-unloading process meets the stability criteria set by IMO A.749(18) Ch 3. The results show the measure of stability in eight conditions with a seven-compartment tank during the loading and unloading process has a higher GZ value in all states, which has met the IMO stability criteria. Comparison of stability calculations on loading and unloading has an average difference of 0.226 m at 2.075 deg at the GZ value in each condition.

ANALYSIS OF FIXED CARBON AND VOLATILE MATTER BRIQUETTES OF PINE SAWDUST AND COCONUT SHELL WASTE

Rany Puspita Dewi, Sumardi Sumardi, Rizal Isnanto — Fri, 15 Dec 2023 00:00:00 +0000

Briquetting technology became one appropriate method that can be used to convert biomass waste into a renewable energy source. Sources of biomass raw materials that have promising potential are pine sawdust and coconut shell waste. Sawdust has potential for about 0.78 million m3/year and coconut shell waste around 360 thousand tons/year. The research aim was to analyse the effect of the carbonization temperature to volatile matter and fixed carbon of briquette. The research was done by variating carbonization temperature at 400 ^oC, 500 ^oC, and 600 ^oC. The result showed that at carbonization temperature of 400 ^oC, the volatile matter and fixed carbon was 42.28% and 55.74%. The volatile matter and fixed carbon are 43.19% and 54.96%, found at carbonization temperature 500 ^oC. The highest fixed carbon 55.98% and the lowest volatile matter 42.19% was found from carbonization temperature at 600 ^oC. The carbonization temperature in briquetting process affects the volatile matter and fixed carbon of briquette.

PENGARUH GEOMETRI DAN PENAMBAHAN JUMLAH SIRIP TERHADAP DISTRIBUSI TEMPERATUR HEAT SINK SEBAGAI ALTERNATIF PENDINGINAN PADA PIRANTI ELEKTRONIK

Fajar Subekti, Slamet Wahyudi, Femiana Gapsari — Fri, 15 Dec 2023 00:00:00 +0000

This study aims to determine the effect of the geometry shape of the copper material heat sink fins on the surface temperature distribution of the heat sink. The material used in this research is pure copper, the shape of the heat sink fins is made rippled with the addition of the number of fins 5, 6, and 7 and the input temperature is varied from 40 C to 80 C with airflow variations from 0.2 m/s to 1 m/s. The first step is to create a heat sink design with Autodesk Inventor. Then the plan is simulated with Autodesk CFD to solve the continuity, momentum, turbulence, and energy equations. Based on the method that has been carried out, it is found that the addition of variations in the number of fins affects the decrease in surface temperature. The highest temperature drop on fin 5 ripples is 24.1 C. The heat energy transfer rate increased by 0.4657 W. The convection heat transfer coefficient increased by 3.47 W/m²C. Nusselt number shows an increase of 271. Fin performance has increased efficiency by 63.4 %, and effectiveness by 1.61. The results of this study are expected to provide practical alternatives that can be widely adopted on a heatsink plate that is very promising for future thermal developments.

PHYSICAL-MECHANICAL PROPERTIES OF PINEAPPLE LEAF FIBRE REINFORCED IN UNSATURATED POLYESTER RESIN FILLED WITH CALCIUM CARBONATE

Fri, 15 Dec 2023 00:00:00 +0000

Using natural fibres is often recommended as polymer composite materials owing to their potential to reduce the pollution of synthetic material waste. This study aimed to obtain the physical properties of unsaturated polyester resin matrix composite containing calcium carbonate fillers of 15 and 30 parts per hundred weights of the resin and natural pineapple leaf fibre of the amount 20% and 30% of the composite weight. The composite samples were three millimetres thick, with the pineapple leaf fibres arranged in one longitudinal direction. Some parameters observed included density, water absorption, response to fire, hardness, tensile strength, modulus of elasticity, and impact strength. The results showed that adding calcium carbonate filler into the matrix increased the density, water absorption, hardness, and modulus of elasticity of the composite. However, it reduced the flame propagation rate, tensile strength, and impact strength. Also, the use of pineapple leaf fibre contributed to increased water absorption, rate of flame propagation, tensile strength, modulus of elasticity, and impact strength of the composite, but it reduced the density and hardness. As these samples use economical materials, they are likely valuable for building materials that do not require high mechanical properties, especially guttering materials.

PERANCANGAN DAN MODIFIKASI MOLD INSERT UNTUK MENINGKATKAN KAPASITAS PRODUKSI LIGHT GUIDE

Fri, 15 Dec 2023 00:00:00 +0000

The use of plastic is often found in human life. Therefore, many manufacturing companies are competing to increase the production and quality of their plastic products. One way to increase production is to redesign a Mold base so that the Mold has a larger production capacity than before. The increase in product demand from consumers, which was initially 65,000 pcs/month to 95,000 pcs/month, is also the background for conducting this research. The purpose of this study is to redesign the soft tool using the old Mold base. The design uses Siemens UG NX 5 software. The Mold used is a two-plate Mold. The manufacture of the core cavity uses NAK 80 steel and plastic raw material in the form of Polycarbonate (PC). At the end of the study, a simulation was carried out using the Moldex 3D Flow Mold software to see the cycle time of the old and new Mold injection processes. From the results of this study, production capacity increased from 67,804 pcs/month to 118,536 pcs/month resulting in twice as many products as the old Mold design, with an increase in cycle time of 14.37% longer than the old Mold design also ensuring the quality of the product is maintained.

KARAKTERISASI BIODEGRADASI PADA KOMPOSIT POLYMER POLYLACTID ACID (PLA) DENGAN PENAMBAHAN CHITOSAN DAN HYDROXYAPATITE

Fri, 15 Dec 2023 00:00:00 +0000

Polylactid Acid (PLA) is a biodegradable polymer made from natural ingredients so it is safe to use for biomaterials. The purpose of this study was to determine the biodegradation characteristics of the addition of chitosan powder and Hydroxyapatite to PLA. There were 4 variations in this study, namely PLA 100 (pure PLA), PLA-chitosan-Hydroxyapatite 94-3-3 (Composite 1), PLA-chitosan-Hydroxyapatite 94-0-6 (Composite 2), PLA-chitosan-Hydroxyapatite 94-6-0 (Composite 3). Samples were prepared using the extrusion method to form filaments, then the filaments were injected with a temperature of 170-190°C and an injection pressure of 5-6 bar. Characterization was carried out using the Immerse Test, FTIR Test, and SEM-EDS Test. The results of the Immerse Test showed an increase in sample mass of 1.04%, 1.1%, 1.05% and 1.14% respectively. FTIR test results did not show any new functional groups in the composite. The results of the SEM test indicated the presence of Na and Cl deposits on the sample surface as evidenced by the results of the EDS test that all samples contained Na and Cl elements. So that the weight gain occurs because the three materials are not chemically mixed which easily separate and cause cavities, these cavities are filled with HBSS liquid.

PERANCANGAN SISTEM HIDROLIK PADA MESIN PRESS BAMBU LAMINASI

Fri, 15 Dec 2023 00:00:00 +0000

The hydraulic system is a power transmission system by using the compressive energy of the fluid into mechanical energy to obtain a power greater than the initial power released. The press machine is one of the pieces of equipment that apply the hydraulic system. In the process of making laminated bamboo, the bamboo gluing technique is assisted using a press machine. Based on observations, the press machine used is a manual press machine, so the pressing process is not efficient. This study aims to increase the effectiveness of pressing laminated bamboo. The results of the study found that the press machine has 4 hydraulic cylinders so the pressing process can be carried out at several points simultaneously. The results of the hydraulic system analysis diagram show hydraulic cylinder moves in 16,9 seconds with a pressure of 100 bar, so the pressing process is fast. Mathematical calculations produce data, a hydraulic gear pump with a displacement of 13 cc/rev, electric motor power of 3,7 kW, hydraulic cylinder diameter of 63 mm, cylinder rod of 35 mm, rod of 400 mm, and a hydraulic tank capacity of 12 liters.

PENGARUH PENGGUNAAN MINYAK JAGUNG UNTUK CUTTING FLUID PADA PROSES FACE MILLING TERHADAP KEKASARAN PERMUKAAN PERMUKAAN DAN LAJU KOROSI BAJA KARBON

Fri, 15 Dec 2023 00:00:00 +0000

The corrosive coastal environment will result in a high corrosion rate for any equipment installed there. This is due to the constant exposure to saltwater, high humidity levels, and strong winds. Therefore, it is crucial to use corrosion-resistant materials and regularly maintain the equipment to ensure its longevity in such an environment. One method to reduce the rate of corrosion is to pay close attention to the manufacturing parameters of these components, one of which is the face milling process. The aim of this study is investigating the effect of face milling process with different dept of cut using minimum quantity lubrication method with corn oil as a renewable vegetable cutting fluid. In this study AISI 316L stainless steel was face milled using HAAS VF-2 CNC machine. The depth of cut is varied between 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm. The results demonstrated that the greater the depth of cut, the greater the surface roughness value that will be generated. It is resulting in increment in the corrosion rate value.

A COMPREHENSIVE REVIEW ON THE NON-DESTRUCTIVE TEST FOR POLYMER MATRIX COMPOSITE

Ari Wahjudi, Agung Sugeng Widodo — Fri, 15 Dec 2023 00:00:00 +0000

Polymer matrix composite (PMC) is widely applied in structural engineering mainly due to its high strength-to-weight ratio. Of many benefits, the transportation industry uses this type of material mainly due to its high strength-to-weight ratio. In many cases, this strength-to-weight ratio is higher than aluminum or steel base materials. Its manufacturing and fabrication, however, are challenging. For this reason, destructive and non-destructive tests to control product quality during the manufacturing process are worked out. The non-destructive test delivers many benefits since the finished product does not. This paper discusses the benefits of polymer matrix composite application in the structural engineering. In addition, this work also outlined the key parameters and comparison of various non-destructive tests applied for the PMC.

DELAYED CRACKING FAILURE OF A FREEZER BARREL

Thomas Albatros, Husaini Ardy — Fri, 15 Dec 2023 00:00:00 +0000

Freezers were used to produce ice cream, pumped by a screw pump into a barrel. The barrel’s outer surface was operated with NH₃ gas at -40^oC and a 12–13 bar pressure. After being in service for 3 years, the unit experienced cracking. The barrel material was Nickel 200, with a base metal average grain size of 48μm. The weld metal has a larger average grain size of 800μm and contains many gas pockets inside and along the grain boundaries, which coalesce one after another, forming micro-cracks that result in intergranular cracking. The weld metal failed in a brittle manner; this embrittlement was attributed to hydrogen atoms ingressing into the weld metal during welding. Atomic hydrogen will diffuse, forming hydrogen gas. Since atomic diffusion takes place over a long period, the occurrence of cracks is well-known as delayed cracking.

UPAYA PERBAIKAN SIFAT MEKANIK BAJA PLAT JOIN G 3131 SPHC MELALUI SIMULASI PROSES INTERCRITICAL ANNEALING DI INDUSTRI KONSTRUKSI BAJA

Imam Nur Fathoni, Alfirano Alfirano, Djoko Muljono — Fri, 15 Dec 2023 00:00:00 +0000

Improvement of the mechanical properties of G3131 SPHC equivalent to JIS G 3101 SS330 plate joint steel through intercritical annealing simulations has been carried out. The JIS G 3131 grade SPHC steel was gradually heated by intercritical annealing at temperatures of 750–850 ^oC for holding times of 1–15 minutes. After intercritical annealing treatment, the tensile strength and yield strength of steel increased compared to non-treatment samples. The average tensile strength obtained was 573 MPa with an increase of 76.85% compared to the tensile strength before the intercritical annealing process. Meanwhile, the yield strength of steel increased by 60% to 421 MPa. Increasing the annealing temperature and holding time will promote the formation of the martensite phase, as well as enlarge the austenite and ferrite grains. Optimal heating variable obtained at a temperature of 750 ℃ with a holding time of 15 minutes. Using these variables produced a tensile strength of 625 MPa and a yield strength of 434 MPa with an elongation of 23% which is standardly included in JIS G 3101 SS400.At the optimal value, the grain growth kinetic of K and n values were 0.280466778 and 0.6905, respectively, with an activation energy (Q) of 12.4268517 J/mol.

PENGARUH TEMPERATUR AUSTEMPERING TERHADAP SIFAT MEKANIK DAN STRUKTUR MIKRO BESI COR KELABU DENGAN NIKEL 10% UNTUK KOMPONEN BOILER PLTU

Fikri Widyansyah, Efendi Mabruri, Alfirano Alfirano — Fri, 15 Dec 2023 00:00:00 +0000

Effect of austempering temperature on microstructure and mechanical properties gray cast iron with 10%wt nickel for boiler combustion application has been studied. Cast iron with the JIS FCD 45 standard with a minimum tensile strength of 414 MPa and a hardness of 187 HB is commonly used for this application. To improve its mechanical properties such as strength and hardness, austempering heat treatment usually applied. Austempering was carried out at 250°C, 300°C, 350°C, 400°C, and 450°C for 1 hour, with the same austenization temperature of 850°C for 1 hour. The highest increase in hardness was found at the austempering temperature of 250°C. The hardness was 321.80 HB or 19.30% of the initial hardness of 259.70 HB. In terms of strength, the highest increase occurred at the austempering temperature of 250°C which was 257 MPa or 31.52% of the initial strength of 176 MPa.

PENINGKATAN SUHU KRITIS PADA SINTESIS BAHAN SUPERKONDUKTOR MAGNESIUM DIBORIDA DENGAN VARIASI UKURAN PARTIKEL SERBUK MG

Fri, 15 Dec 2023 00:00:00 +0000

Studying the evolution of the MgB₂ superconductor manufacturing process to improve critical temperature is important. The solid-state approach was used in this work to create a low-cost MgB₂ superconductor. Variations in the purity of Boron were used as control parameters to evaluate the impact of dry milling on the production of the MgB₂ bulk and low-temperature electrical properties. A 2:1 stoichiometric ratio of magnesium and boron powder was weighed and ground for 30 minutes. The ground powder was compressed and sintered for one hour at 1073 K. We were able to confirm through XRD and SEM research that the small particle size improved the MgB₂ phase fraction and increase crystallite size in the production of the MgB₂ sample. At 1073 K and 200 um of Mg, the sample sintered produced an MgB₂ phase of 99.3%. The critical onset temperature (Tc-offset) improved from 39 to 40K, respectively.

TRIBO-CORROSION INVESTIGATION ON MATERIAL 316LX MANUFACTURING RESULT OF 3D PRINTING MATERIAL ADDITIVES IN 5% H2SO4 SOLUTION

Fri, 15 Dec 2023 00:00:00 +0000

Tribocorrosion is a type of material degradation caused by simultaneous wear and corrosion of metal surfaces caused by laminar or turbulent flow. Additive manufacturing technology plays an important role in its application to precision components and complex assemblies. This study developed a 316LX material with Fe, Ni, Cr, and other powder alloys that was processed into an ultra-protective wire as a 3D printing filler. This simulation of tribocorrosion conditions was performed on a triboester machine. This simulation is expected to provide important insights and understanding into the behavior and properties of the 316LX 3D printing material, especially when exposed to abrasion and corrosion conditions in a sulfuric acid solution environment. Corrosion Rate Testing of 316LX Material Additives Using Potentiodynamic Methods in a Modified Rotating 5% Sulfuric Acid Fluid. In addition to corrosion rate, the Vickers hardness, metallography, and shrinkage of the 316LX green part material were also tested at 1000^oC after sintering.

PEMETAAN KOROSIFITAS ATMOSFER MENGGUNAKAN LOGAM BAJA KARBON RENDAH DAN KARBON TINGGI PADA WILAYAH KOTA SURABAYA

Fri, 15 Dec 2023 00:00:00 +0000

Corrosion of metals is inevitable. One of the factors that affect corrosion is environmental conditions that contain pollutants like SO₂, NO₂, and Cl^- which are found in many industrial and seaside areas. Surabaya is an area that has 2 types of conditions. In addition, Surabaya is the capital of the province where infrastructure development is running rapidly. Thus, this study maps the level of atmospheric corrosion in five areas in Surabaya by collecting corrosion rate data for 4 months with weight loss method using AISI 1020 Steel and SK5 Steel as test metals. XRD and SEM-EDX tests were conducted to compare the corrosion results. The average corrosion rate of low carbon steel was 0,6561 mpy and high carbon steel was 1,2523 mpy. The results concluded that the high level of atmospheric corrosivity of low carbon steel is in Sukomanunggal, Bulak, Rungkut, Pakal, Krembangan, and Bubutan sub-districts. The medium level is in Tegalsari, Gubeng, Tenggilis Mejoyo, Karang Pilang, Jambangan, Sawahan, and Dukuh Pakis sub-districts. The low level is in Lakarsantri, Mulyorejo, Simokerto, Sambikerep, Genteng, and Wonokromo sub-districts. Meanwhile, high atmospheric corrosivity levels for high carbon steel are in Krembangan, Karang Pilang, Bulak, Tenggilis Mejoyo, Pakal, and Jambangan sub-districts. The medium level is in Rungkut, Sawahan, Bubutan, Wonokromo, Tegalsari, Sukomanunggal, and Lakarsantri sub-districts. The level is in Dukuh Pakis, Genteng, Gubeng, Simokerto, Sambikerep, and Mulyorejo sub-districts. This mapping is based on the level of corrosion in each sub-district which is influenced by the presence of industry and its geographical location.

ANALISIS PENGARUH VARIASI HOLDING TIME ANNEALING TERHADAP LAJU KOROSI TITANIUM PADA LARUTAN CAIRAN TUBUH SINTETIS

Fri, 15 Dec 2023 00:00:00 +0000

Biomaterials are crucial for bone implants due to their biocompatible and inert nature, ensuring no adverse effects within the human body. Titanium is renowned for its exceptional corrosion resistance. This research aims to analyze the impact of annealing holding time and pH of synthetic body fluid on the hardness and corrosion rate of titanium. The annealing process was performed at 700°C, with holding times of 30, 60, and 90 minutes. As an electrolyte medium, a Hanks' solution with pH variations of 4, 6, and 8 was used and maintained at 37°C. Potentiodynamic corrosion testing demonstrated the lowest corrosion rate in specimens treated with 30 minutes of annealing at pH 8, measuring 0.32 x 10-2 mmpy. The 30-minute annealing exhibited the lowest corrosion rate, which was confirmed by Electrochemical Impedance Spectroscopy (EIS) results showing a higher Rp value, indicating a lower corrosion rate. This is attributed to the presence of a passive Rutile TiO2 layer formed during the annealing process, as confirmed by X-ray Diffraction (XRD) analysis. Metallography observations indicated that the microstructure of untreated specimens consisted of α and β phases. Scanning Electron Microscopy (SEM) analysis of specimens annealed for 30 minutes revealed an oxide layer on the surface without any visible pores. However, an increase in annealing holding time led to the formation of pores, particularly noticeable after 90 minutes of annealing. The presence of pores in the oxide layer resulted in an increased corrosion rate with longer annealing holding times. Conversely, hardness testing demonstrated that longer annealing holding times resulted in higher hardness values.

THE EFFECT OF PYROLYSIS DURATION ON THERMAL CONDUCTIVITY, STABILITY, AND VISCOSITY OF DISPERSED PCB-BASED PARTICLES IN THERMAL FLUID

Fri, 15 Dec 2023 00:00:00 +0000

Solid particles have a higher thermal conductivity compared to a fluid. Therefore, it is a common practice to disperse solid particles inside a base fluid to increase its thermal conductivity. The particle-dispersed fluid is called a thermal fluid. Thermal fluid, such as a coolant, is widely used as a heat transfer fluid. Several types of particles can be used to increase the thermal conductivity of the fluid, i.e., metallic particles, metal-oxide particles, or even carbon-based particles. In this research, a carbon-based particle was used as the dispersed particle. The particle was obtained by processing electronic waste, specifically Printed Circuit Board (PCB). The PCB was pyrolyzed for variable duration at 15, 30, and 45 minutes to increase the carbon content. After pyrolyzing, the particle was milled to reduce its size. Subsequently, the PCB particle was added to distilled water. Sodium Dodecylbenzene Sulfonate (SDBS) was added as a surfactant to increase fluid stability and prevent particle agglomeration. Thermal conductivity was improved by up to a 13% increase at the 15-minute pyrolysis. Adding SDBS surfactant also improves the thermal fluid's stability to -29,1 mV. The fluid's viscosity was slightly increased up to a maximum of 0.984 mPa.S.

PENGECORAN ALUMINIUM MATRIKS KOMPOSIT BERPENGUAT CARBON NANOTUBE (CNT) DENGAN VARIASI PENAMBAHAN SERBUK MAGNESIUM

Muhammad Syahid, Elyeser Elyeser, Azwar Hayat — Fri, 15 Dec 2023 00:00:00 +0000

Aluminum matrix composite reinforced CNT have been developed to improve the mechanical properties of aluminum. In this study, the melting of Aluminum 1100 reinforced Carbon Nanotube (1 wt.% CNT) with variations in the addition of Magnesium powder was carried out by the slurry-based method. The casting of the specimens is carried out using a metal mold. CNT powder was first mixed with magnesium powder at 60°C. Then the aluminum is melted to a temperature of 700°C until it melts, then the temperature is lowered to 500°C or the texture has changed to be like mush (slurry based) and then mixed with CNT powder and Magnesium powder are added. After that the alloy was raised again at 720°C for 30 minutes and the stirring process was carried out, after that it was poured into a metal mold with a mold temperature of around 400°C. The samples were then analyzed for mechanical properties and microstructure observations. The results of the Vickers hardness test before the addition of Mg powder and CNT were 36.7 HV. While after the variation of adding 1wt.% Mg powder, the hardness of the specimen increased to 44.5 HV, the variation of adding 3% Mg powder was 45.3 HV, and the variation of adding 5% Mg powder reached a hardness value of 46 HV. The tensile test results on 3% Mg powder is 241.6 MPa. The wear test results show the wear rate value for the 1% Mg variation of 0.146 mg/s, the 3% Mg variation of 0.106 mg/s, and the 5% Mg variation with a wear rate value of 0.093 mg/s. The α-Al phase is the dominant phase formed, where the grain size and grain boundaries in the 3% Mg variation have a relatively small size and the spread of CNT is evenly distributed in the alloy, so the addition of Mg to the alloy can help spread CNT in Aluminum alloys.