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The carburizing process involves adding carbon components to the steel surface at an austenite temperature to harden it. The goal of this study was to see how the process of carburizing ST 60 steel at 825°C for 4 hours using wood charcoal that had been converted into carbon affected the microstructure and surface hardness. Microstructure testing is used to detect the steel's phase after it has been carburized. The goal of hardness testing is to assess the material's hardness following the carburizing process. The carbon sieving procedure produced a dry carbon size of 100 mesh with a particle size of 554.621m2 and a wet carbon size of 500 mesh with an average area of 113.542m2 of carbon particles. Based on the findings of the tests, it can be assumed that following the carburizing process, the number of carbon particles would decrease. Carbon was lost at a rate of 33.58 percent, with an average particle area of 554.621m2. Carbon with an average particle area of 113.542m2 was lost by 9.91 percent. According to the Vickers hardness test, the raw material's average hardness from points 1 to 5 is 280.42kg/mm2. Steel with a hardness of 1-5 points is carburized with an average area of 554.621m2 carbon particles with a density of 214.56kg/mm2. The area of carbon particles in carburizing steel is 113.542m2, and the average hardness value is 245kg/mm2. [ABSTRACT FROM AUTHOR]

The purpose of this research is to determine the effect of casting mold inlet (In-Gate) diameter on chemical composition, porosity defects, micro-photographs, and casting product hardness. The casting sample material is made from scrap aluminum and poured into the mold in 5mm, 7.5mm, and 10mm In-Gate diameter variations. Chemical composition testing, porosity observation, microphotography with a metallography microscope, and Brinell hardness testing (ASTM E– 10 standard) are used to collect data for this investigation. The result indicates that the sample aluminum alloy silicon metal (Al-Si) material has an 81.86 percent aluminum content and a 9.84 percent silicon content. The 10mm In-Gate size has the highest hardness value of 98.68 BHN, while the 7.5mm In-Gate has a hardness value of 84.46 BHN. Due to porosity defects that can reduce metal hardness, the 5mm In-Gate has the lowest hardness value of 73.07 BHN. [ABSTRACT FROM AUTHOR]

A grinder is a tool used in manufacturing processes such as finishing workpieces and smoothing cuts or welding products, and it can also be used to sharpen metal tools such as knives and chisels with an abrasive material. In this study, the wear rate of a self-manufactured grinding stone made from aluminum slag treated with HCl as the abrasive material was compared to grinding stones from previous studies and commercial grinding stones sold on the market using the ASTM D-3702 standard wear test. The self-manufactured grinding stone was made of liquid and powder phenolic resins, cast aluminum slag, water and HCl-treated meshes 12 and 40, and fiberglass mesh fibers. The mixture is then combined with a predetermined composition. The mixture is then placed in a mold and compacted for 5 minutes with a press machine with a force of 15 tons, allowed to stand at room temperature for at least 24 hours, and sintered at 140 degrees Celsius for 1 hour. The results showed that the average wear value of the grinding stone with HCl treatment is higher than the wear value of the grinding stone with water treatment, which is 0.0664 gram/minute and 0.0129 gram/minute, respectively. The commercial grinding stone had the lowest average wear value of 0.0031 gram/minute. Surprisingly, the wear value of commercial grinding stones is lower than the wear rate of self-designed grinding stones. [ABSTRACT FROM AUTHOR]

The metal will experience a phase change during the casting process, both changes in physical and mechanical properties caused by the freezing process. Changes in these properties are influenced, among others, by the cooling medium used during the cooling process. Because the physical and mechanical properties of a metal are very important in machinery construction, in this study different cooling media were used, namely: seawater, well water, and SAE 40 oil. The purpose of this study was to determine the effect of different cooling media on seawater, water wells, and SAE 40 oil on the chemical composition of brass cast products, hardness, and microstructure of brass castings. From the hardness test, the test object with seawater media has a better hardness value than well water and SAE 40 oil. From the results of testing the chemical composition, there are 18 elements, but only 4 elements have the most influence on cast brass, namely: Cu, Zn, Fe, and Sn are the most dominant. Judging from the elements present in this material, it can be classified as brass, and zinc alloy (Cu-Zn). [ABSTRACT FROM AUTHOR]

This study examines the density, porosity, microstructure, and hardness of aluminum raw materials from used pistons using gravity dies casting and gravity investment casting processes. Gravity die casting and gravity investment casting at a casting temperature of 750°C were employed in this research. Emission Spectrometry is used to determine the chemical composition of a substance (ASTM E-1251). Porosity was measured using macro photography and a digital microscope, with the findings of each mold temperature fluctuation compared. The Rockwell hardness tester is used to determine the hardness of a material (ASTM E-384). A metallographic microscope was used to examine the microstructure of the castings (ASTM E3-11). According to ASTM B-85 standards, this material comprises 71.05% (Al) composition, 13.65% (Si), 7.178% (Cu), 3.4508% (Fe), 1.7870% (Zn), and additional components up to 100%, and is categorized as Aluminum Al-Si (Aluminum-Silicon)A413.0. The density of the test object was calculated using gravity die casting at 2.6972 gr/cm3 and gravity investment casting at 2.6764 gr/cm3. The quantity of porosity impacts the density value, according to the results of porosity observations. The phase (Al) and the phase (Zr) are observed in the microstructure results (Si). In gravity investment casting, the beta phase granules (Si) appear to be larger and fewer. The beta phase granules seem smaller and more abundant in gravity die casting. The hardness value is influenced by the size, number, and dispersion of beta granules. Hardness testing with gravity investment casting yielded a hardness value of 86.84 HVN, according to the results. [ABSTRACT FROM AUTHOR]

When used as a friction-prone component, commercially pure titanium must be hardened. Plasma nitrocarburizing can increase the hardness of commercially pure titanium. N2 and CH4 gases are used as nitrogen and carbon ion sources in plasma nitrocarburizing. The objective of this work is to investigate how the ratio of N2 to CH4 gas flow rates affects the thickness and hardness of the thin layer created. At a pressure of 1.6 mbar and a temperature of 450 oC, plasma nitrocarburizing was carried out for 4 hours with different gas flow rate ratios of 1:1, 1:2, 1:3, and 1:4. To analyze the microstructure and surface composition of the material, a metallographic test was performed using a ZEISS EVO Scanning Electron Microscope-Energy Dispersive Spectrometry. To determine the compounds formed, a composition test was conducted using X-ray Diffraction (XRD) with the brand Pw3040 60 X Pert Pro Mpd Diffractometer. The Matsuzawa MMT-X7 Micro Vickers Hardness tester was used to measure surface hardness. Hardness testing on commercially pure titanium nitrocarburized plasma with variations in gas flow rate ratios of 1:1, 1:2, 1:3, and 1:4 resulted in hardness of 312.68 VHN, 134.96 VHN, 111.56 VHN, 109.3 VHN, respectively. The metallographic test by using Scanning Electron Microscope results showed the formation of a thin layer. The thicknesses were 1.88 µm, 1.69 µm, 1.65 µm, and 1.44 µm. This thin layer was confirmed by a composition test formed from TiN and TiC compounds. The plasma nitrocarburizing technique increased the hardness of commercially pure titanium, according to the test results, however, when the flow rate of CH4 was increased by a ratio of 1:2, 1:3, and 1:4, there was a decrease in hardness compared to a ratio of 1:1. Plasma nitrocarburized commercially pure titanium has the potential to be used in the medical field as a material for hip joint arthroplasty. [ABSTRACT FROM AUTHOR]

Plastic product development requires dimensional accuracy in the product. One method to improve the accuracy of dimension is by making a mold that has a uniform cooling channel following the contour of the cavity, so that the direction of product shrinkage on cooling cycle can be uneven. The existing solid-type mold has several limitations on the cooling channel system. Meanwhile, products with complicated shapes mostly require cooling channel that follows the shape of the cavity (conformal). Type of conformal cooling channels can be made by the method of manufacturing each layer laminate plate arranged with adhesive into a single unit (laminated steel tooling) and the method of using a resin molding mixed with metal powder in which there is a pipe that follows the shape of the cavity (soft tooling). The present study compares the shrinkage of plastic products made from three types of mold, namely: a solid mold with straight cooling channel, laminated steel tooling with conformal cooling channel, and soft tooling with conformal cooling channel. Analysis of shrinkage measurement products includes high direction and inside diameter and outside diameter of elongated cylindrical products. Three types of mold were made, namely mold with a straight cooling channel, laminated steel tooling mold with conformal channel, and soft tooling mold with conformal channel. Three specimens were made from each mold. Plastic material for injection was Polypropylene. The volume of cooling channels between the straight-type channel and conformal was set equal. Data were collected after the injected products were stored for 24 hours. The results show that the percentage of both shrinkage lamination conformal cooling system and soft tooling is smaller when compared to that of a straight cooling system. Moreover, the shrinkage difference of diameter dimension on the X axis and Y axis is insignificant. It proves that the lamination conformal cooling systems and soft tooling are more optimal in controlling the shrinkage dimensions of the product. [ABSTRACT FROM AUTHOR]

Hip Joint is located between the hip and the base of the upper femur. Diseases such as osteoarthritis and rheumatoid arthritis can cause total replacement of hip joints with prosthesis. Hip joint prosthesis’s components consist of acetabular cup, femoral head, and femoral stem. One of acetabular cup material is a polymer. Therefore, injection molding is one of the processes that can be used to produce it. The problem that often arises is a product defect due to shrinkage. Regarding to shrinkage, the research will investigate the effect of water cooling on the shrinkage of the product’s size in the injection molding process of making acetabular cup. The work begins with the manufacture of molds, then two injections of liquid polypropylene are carried out into the mold. The first injection is for mold without cooling and the second with cooling. The resulting shrinkage is then compared. The shrinkage measurement of the outer part of the product is taken from three directions, namely the product's height, the product's outer diameter in the direction of y axis, and the outer diameter of the product in the direction of z axis. For the interior of the product with a half-ball shape, shrinkage measurements are carried out by measuring the average radius. Test result shows that shrinkage in injection molding testing with cooling is lower than injection molding testing without cooling. The average shrinkage of the product’s height on the test with cooling is 1.224%, while the test without cooling is 1.591%. The average shrinkage of the outer diameter in the direction of y axis on the test with cooling is 1.857%, while the test without cooling is 2.32%. The average shrinkage of the outer diameter in z axis on the test with cooling is 1.83%, while the test without cooling is 2.369%. Measurement the average shrinkage of the product's radius is also obtained the similar trend. The test with cooling obtains the average shrinkage of the product's radius of 0.825%, while the test without cooling is 1.267%. [ABSTRACT FROM AUTHOR]

In this work, the effect of the Ni underlayer with different thicknesses on the mechanical properties of Cu surface was studied. A laminated structure of Ni/Cu layer was prepared using electroplating on carbon steel substrates. The nickel layer was firstly plated on the steel using a current voltage of 2.3 V and varied plating times using 30, 60, 90, 120 and 150 minutes. The copper layer was subsequently electroplated on the nickel surface using a fixed current voltage of 1.9 V and plating time of 30 minutes. The result showed that XRD pattern observed on the surface of Ni/Cu coating indicates the formation of Cu single phase instead of Ni/Cu alloy. Application of plating time variations on the Ni underlayer using 30, 60, 90, 120 and 150 minutes produced an average thickness of Ni underlayer with 19.9, 48.4, 50.1, 62.1 and 64.9 µm, respectively. The thickness of Cu as the outer layer for different thickness of Ni was kept constant at approximately 23.66 µm. The hardness measurement on the Cu underlayed by Ni deposited using different plating times indicated that the hardness of Cu was 91.63, 93.20, 97.93, 102.60 and 106.1 HV, respectively. Whereas, the specific wear rates of Cu were 6.59 × 10-6, 6.11 × 10-6, 5.99 × 10-6, 3.63 × 10-6 and 3.55 × 10-6 mm3/kg.m, respectively. The present study showed that the mechanical properties of Cu layer surface with a fixed layer thickness were influenced by the application Ni underlayer with different thicknesses. An increase of Ni underlayer thickness has increased the hardness and specific wear rate of the Cu layer. [ABSTRACT FROM AUTHOR]

In this work, a laminated structure of Cr-Ni coating was prepared using electroplating on carbon steel substrates. Two baths of chrome and nickel electrolyte solutions were prepared to deposit laminated Cr and Ni layers. Chrome was firstly plated on a steel substrate in constant routes whereas nickel was subsequently electroplated on the Cr coating using varied plating times. The effect of Ni plating time on the thickness, hardness and wear specific of the Ni layer was investigated. The results show that an increase of plating times increased the thickness and hardness of the Ni layer, but reduced the wear specific. This study showed that Ni can be a potential candidate as a material replacement for chromium plating maintenance. [ABSTRACT FROM AUTHOR]