AISI 1020 steel is categorized in low carbon steel which widely used for automotive parts industry and construction because its characteristic like high ductility, relatively low hardness value, and high formability. In continuously usage for long time, this steel tends to be worn down because its low surface hardness value. The surface hardness is congruity to wear resistance of AISI 1020 steel. In this research, the experimental method of pack carburizing process was carried out by heating AISI 1020 steel samples packed along charcoal with catalysts variation of Na2CO3 and CaCO3 till temperature 900 oC and hold it for 4 hours to effect diffusion carbon mechanism in surface treatment. Thereupon, AISI 1020 steel samples was fast cooled by using distilled water. The selection of different catalyst variation according to diffusion capability which will be expected to enhance AISI 1020 steel’s microstructure and mechanical properties. From this research, it obtained that pack carburized AISI 1020 steel using Na2CO3 possesses significant microstructure transformation which will affect to the highest hardness value increment (505,4 HV) and the lowest wear rate decrease (0,00821 mm3/minute). Thereby, pack carburized AISI 1020 steel using Na2CO3 also exhibits good wear resistance characteristic so that can be used in long lifetime.
Salah satu penopang perekonomian di Desa Cikahuripan Kabupaten Sumedang adalah kelompok petani biji kopi yang tergabung dalam Lembaga Masyarakat Desa Hutan (LMDH) Hurip Raharja. Kelompok ini memiliki total lahan produksi sebesar 15 Hektar dengan rata-rata total pertahun menghasilkan 50 ton biji kopi segar (ceri). Kondisi saat ini, hasil panen biji kopi ceri dijual dengan harga sangat rendah yang disebabkan oleh belum adanya mesin pengupas biji kopi (pulper) yang dimiliki para petani kopi. Berdasarkan permasalahan tersebut, maka sebagai salah satu solusi yang diterapkan adalah dengan melakukan proses pembuatan mesin pengupas biji kopi ceri berkapasitas 150 kg/jam dan dilanjutkan dengan pendampingan implementasi mesin tersebut pada dalam LMDH Hurip Raharja. Mesin pengupas biji kopi bekerja dengan cara sistem pengerolan melalui dua buah rol yang berputar dengan perbedaan permukaan kasar dan halus agar dapat melakukan pemisahan biji kopi dari kulitnya. Transmisi mesin menggunakan jenis V-Belt dengan motor penggerak listrik. Hasilnya berupa mesin pengupas biji kopi dengan efisiensi sebesar 70 % dari total 10 kilogram biji kopi. Untuk mempermudah pengoperasian dan perawatan mesin, maka telah dilaksanakan implementasi kepada LMDH Hurip Raharja berupa pelatihan bimbingan teknis menggunakan mesin pengupas biji kopi. Dengan demikian, mesin pengupas biji kopi (pulper) ini diharapkan dapat meningkatkan produksi petani kopi di Desa Cikahuripan Kabupaten Sumedang.
Welding is one of the metals joining methods to assembly parts which are used in manufacturing, automotive, and aerospace industries. The welding process merely simulated in modelling using finite element method (FEM). Simulation is used to determine how the effect of welding speed on the distribution of temperature, residual stress, and deformation in the V-Butt Joint welding model. The material used in this welding simulation is AISI 1045 plate with a thickness of 8 mm. Variable speed of welding performed in 30 cm/minute, 40 cm/minute and 50 cm/minute. As the result, the residual stress and distortion will be compared in order to find the best welding speed which produces the smallest residual stress and distortion value. Welding simulation based on SMAW with 6.3 mm of E7016 electrode, current of 150 A, voltage of 26 V, and single-pass welding. The finite element method using the ANSYS 2020 R2 software for simulation. Welding simulation uses transient thermal and moving heat flux features, while residual stresses and distortion use static structural features. From this research, the maximum temperature distribution after welding at welding speeds of 30 cm/minute, 40 cm/minute and 50 cm/minute were 295.22 ℃, 240.59 ℃ and 205.94 ℃, respectively. In this study, the welding speed of 30cm/minute has the highest values of residual stress and distortion, which is about 0.00000036965 MPa and 0.090894 mm. Besides, for welding speed of 40 cm/minute and 50 cm/minute, the total residual stress and total distortion value are 0.00000027744 MPa; 0.067248 mm and 0.00000022218 MPa; 0.053419 mm, respectively.
Indonesia has long coastal line surrounding the country, so it becomes a maritime country. Due to this situation, the country was endowed to numerous trading via sea by utilizing numerous harbors. In harbors, there were several activities specifically about heavy equipment lifting and loading. To uplift the heavy equipment, it is necessary to develop such tools which capable to result the lifting force. Lifting crane which extensively used for heavy equipment lifting is designed to tackle that problem. The design process of lifting crane involves several efforts of planning, design process, and numerical simulation. The planning step used initial and conceptual criteria based on references. Afterwards, the design process was developed by using computer aided design of Solidworks. The numerical simulation was carried out by using ANSYS R2 2020. The design process of lifting crane has successfully done which present a comprehensive framework to model the lifting crane of capacity 300 kilograms. The resulted design of lifting crane also meets with the safety requirement for heavy equipment lifting and loading. Therefore, the result of this research would facilitate PT. Pelabuhan Indonesia to improve the lifting crane tool with high safety and robust loading capacity.
Manganese steel is a special alloy steel which has good mechanical properties, especially high ductility and toughness values. This steel has high work hardening capability so it will be easy to engineer. In industrial applications, this steel is susceptible to a decrease in the value of its mechanical properties such as the hardness value due to continuous loading. From these problems, a steel engineering process is needed in order to significantly improve the mechanical properties of steel so that it has good durability and lifetime. This study aims to determine the effect of holding time of heat annealing treatment process on the microstructure and mechanical properties of austenitic manganese steel. This research was conducted by heating the annealing process at a temperature of 1000 oC with four variations of holding time for 0, 40, 80, and 120 minutes. After the austenitic manganese steel specimen is heated for a certain time, it is then subjected to very high temperature cooling (in the furnace). The steel specimen is then prepared for metallographic testing and mechanical properties (hardness) testing. Metallographic testing is carried out to be able to analyze the microstructure formed in the austenitic manganese steel specimens after undergoing annealing process. From the metallography results, it was found that the effect of holding time on the annealing process affected carbide precipitation at the grain boundaries in the austenite matrix of manganese steel specimens. In the annealing process with a holding time of 80 minutes, the austenitic manganese steel showed a microstructure with perfect carbide precipitation at the grain boundaries so that this would have an effect on a significant increase in the hardness value. From the results of the hardness test, it was also found that the hardness value of steel specimens by annealing process for 80 minutes was 39.5 HRc. Thus, the effect of the optimal holding time of the annealing heat treatment process to improve the microstructure and mechanical properties (hardness value) is 80 minutes.
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