Purpose The purpose of this paper is to analyze the failure of the left waterwall tube of a boiler furnace in the steam power plant which led to cracks and rupture. Macro visual observation showed the rupture like a fish mouth with slag adhering at the outer surface of the tube. Magnetite as a protective layer was peeled off. Changes in the thickness were analyzed through dimensional measurement. In this research, an analysis to find the cause and determine the fracture mechanism is presented. Design/methodology/approach A physical analysis was performed through visual observation of changes in the thickness. Micro visual testing with a metallography test provided the data required to measure the change of grain size. The mechanical analysis used Von Mises criteria and API 530 standard and provided the pressure limits data. Findings The thickness of the tube decreased at the peak curvature of the tube. The smallest thickness at the peak curvature of the tube was 0.108 inches. The working pressure was 40.74 percent from permit limits with Von Mises calculations. The percentage of pressure calculated by the API standard was 48.42 percent from permit limits. Larger crystal grains occurred only in the nearby area of the oxide layer and at the end of the crack tip. It indicated that part of the inner surface had a relatively high temperature and plastic deformation occurred because of the pressure from inside the tube. Combining all these factors ruptured the tube at this location because the cross-section could not hold up the pressure. Originality/value The analysis of this discussion focuses on the combined effect of those factors causing the ability to decrease stress being received. It restricts the tube from holding up the stress and furthermore it will generate fractures.
The development of technology in manufacturing is currently very fast. One of the important processes involved is joining, including the process of resistance spot welding or better known as spot welding. The use of point welding has several advantages, including a neat shape of the joint, the process is faster, the connection is tighter and the operation is relatively easy and does not require filler metal. The connection of relatively thin plate-shaped steel using resistance spot welding is an alternative option that is widely used by the automotive parts production industry. However, there are no data regarding the best time and data regarding the hardness test, nugget diameter, and shear test on SPCEN steel material. This study aims to determine the effect of spot welding time on hardness, shear strength and nugget diameter on SPCEN steel material. This study used an experimental method with a time variable of 1 second, 2 seconds and 3 seconds with standard material SPCEN JIS G 3141, standard hardness testing using DIN 50103 and standard shear testing using ASTM D 1002. equal that is 3.3 mm. The lowest average nugget hardness results are found on steel plates marked with the name ABC, time of 1 second with an average nugget hardness of 116.6 HRB and the highest average nugget hardness is found on GHI steel within 3 seconds with an average nugget hardness of 117 , 9 HRB. The lowest average yield of shear strength is found in ABC steel at 1 second with a maximum shear strength of 294.82 N / m² and a maximum load of 1592.01 Newton, the highest average yield of shear strength is found on steel plates marked with the name GHI time 3 seconds with a maximum tension of 415.89 N / m² and a maximum load of 2245.83 Newton. Thus the longer the spot welding time (spot welding), the greater the current used, the greater the heat generated and the hardness and shear strength become stronger. Shows the best time for spot welding (spot welding) of 1.6 mm SPCEN steel plate in 3 seconds.
Many environmentally friendly automotive technologies have been developed to support the blue sky program. Among the several innovations, metallic catalytic converter (MCC) technology used in environmentally friendly motorcycle exhausts system with titanium dioxide (TiO2) is one of the innovations available to reduce the rise in air pollution due to exhaust emissions. In terms of reducing exhaust emissions, this technology certainly does not doubt its ability. But the problem is that not many researchers have examined the effect of the application of these technologies on engine performance. Thus, the high aim of this study is to analyze the effectiveness of the use of TiO2 based MCC on the four-stroke motorcycle engine performance. This type of experimental research uses a Yamaha Vixion motorcycle as an object of research. Engine performance testing is performed based on SAE J1349, namely Engine Power Test Code-Spark Ignition and Compression Ignition-Net Power Rating. The equipment used in this study is the inertia of the chassis dynamometer, digital tachometer, digital thermometer, humidity meter, and blower. The independent variables in this study are the standard muffler and modified muffler with TiO2 based MCC. The control variables are engine speed, engine oil temperature, ambient air temperature and humidity, and Pertamax fuel, while the dependent variable is engine performance (torque, power, and fuel consumption). Data analysis techniques using quantitative descriptive methods. This study found that the use of environmentally friendly motorcycle mufflers with TiO2 based MCC technology could increase the torque of the Yamaha Vixion motorcycles. In line with these results, vehicle power also increases, and fuel consumption is relatively economical if the TiO2-based MCC is compared to standard exhaust.
ABSTRAKProgram Studi (Prodi) S1 Teknik Mesin adalah salah satu prodi di Jurusan Teknik Mesin Universitas Negeri Surabaya (Unesa) yang memiliki bidang penjurusan otomotif dan produksi. Dalam memenuhi tugas tri dharma perguruan tinggi seorang dosen harus melakukan tugas pokok, dua diantaranya adalah penelitian dan pengabdian kepada masyarakat. Dari data hasil laporan borang akreditasi S1 Pendidikan Teknik Mesin pada tahun 2011, data dosen terbanyak melakukan penelitian adalah dengan sumber pembiayaan yang berasal dari depdiknas yaitu TS-2 sebanyak 12 orang, TS-1 sebanyak 14 orang, dan TS mengalami penurunan sehingga jumlahnya menjadi 2 orang. Hasil maksimal terdapat pada dosen yang melakukan pengabdian kepada masyarakat dengan pembiayaan yang berasal dari Depdiknas, yaitu 10 dosen pada TS-2, 7 dosen pada TS-1, dan 9 dosen pada TS. Pada penelitian ini kajian yang menyangkut kinerja dosen dibidang penelitian dan pengabdian kepada masyarakat berupa pelacakan terhadap kinerja 11 dosen dalam tiga tahun ajaran terakhir, yang dimulai pada tahun 2012/2013. Kajian menggunakan metode deskriptif dengan pendekatan kuantitatif. Data jumlah penelitian dan pembiayaan didapatkan dari Unit Penjaminan Mutu, sedangkan data pendukung didapatkan dengan melakukan survei acak terhadap mahasiswa dan terhadap lima belas dosen di Jurusan Teknik Mesin. Berdasarkan hasil yang dicapai penelitian dosen-dosen selama tiga tahun ajaran mengalami penurunan dari beberapa segi pembiayaan, namun mengalami peningkatan pada pembiayaan oleh universitas di tahun ajaran 2013/2014 dan menurun pada tahun ajaran 2014/2015. Pada pengabdian kepada masyarakat mengalami peningkatan dari variasi pembiayaan dimana pada tahun ajaran pertama hanya dibiayai Depdiknas namun pada tahun ajaran kedua dan ketiga sudah ada pembiayaan oleh perguruan tinggi. Kegiatan penelitian dan pengabdian kepada masyarakat dengan pembiayaan sendiri masih belum ada. Berdasarkan hasil angket kepada mahasiswa, sebagian besar memiliki keinginan dilibatkan dalam kegiatan penelitian dan pengabdian masyarakat yaitu sebesar 54%. Berdasarkan angket terhadap dosen menunjukkan minat yang tinggi terhadap kegiatan penelitian dan pengabdian masyarakat sebesar 87%. Kata Kunci: akreditasi, deskriptif kuantitatif, penelitian, pengabdian kepada masyarakat, variasi pembiayaan. ABSTRACTThe Mechanical Engineering Study Program (S1) is one of the study programs in the Department of Mechanical Engineering, Surabaya State University (Unesa), which has automotive and production majors. In fulfilling the tri dharma task of a tertiary institution, a lecturer must perform basic tasks, two of which are research and community service. From the results of the accreditation forms report S1 Mechanical Engineering Education in 2011, the most lecturer data conducted research was with funding sources from the Ministry of National Education, namely TS-2 as many as 14 people, TS-1 as many as 14 people, and TS decreased so that the number became 2 person. Maximum results are found in lecturers who do community service with funding from the Ministry of National Education, namely 10 lecturers at TS-2, 7 lecturers at TS-1, and 9 lecturers at TS. This study was involving the performance of lecturers in the field of research and community service in the form of tracking the performance of 11 lecturers in the last three academic years, which began in 2012/2013. The study uses descriptive methods with a quantitative approach. Data on the amount of research and financing was obtained from the Quality Assurance Unit, while supporting data was obtained by conducting a random survey of students and fifteen lecturers in the Department of Mechanical Engineering. Based on the results achieved by the research of the lecturers during the three academic years, there was a decrease in several aspects of funding, but an increase in funding by the university in the 2013/2014 academic year and decreased in the 2014/2015 school year. In community service, there has been an increase in the variation of funding where in the first academic year it was only funded by the Ministry of National Education, but in the second and third academic years there was already funding by universities. Research and community service activities with self-funding are still lacking. Based on the results of the questionnaire to students, most of them had the desire to be involved in research and community service activities in the amount of 54%. Based on the questionnaire towards the lecturers, it showed a high interest in research and community service activities by 87%. Keywords: accreditation, quantitative descriptive, research, community service, financing variations.
Visual observation on waterwall tube failure showed crack at the outer surface and fish mouth on reheater tube. An analysis of this research is to compare the causes of failure of waterwall and reheater tube boiler. Method of this used descriptive qualitative with macro and micro visual observation. Crack appeared from the outside waterwall tube occurred at a place attached to the oxide layer, it indicated that failure on this tube achieved in long period. The small crack as a place for new oxide layer and corrosive media. Larger crystal grains at the edge of the oxide layer and tip of crack because the corrosion reaction between oxides and metal, it produces local heat on the area. Failure on reheater tube was presence of scale attached on the outer caused differences in the distribution of temperature between inner and outer surface tube.The dominant factor of this failure occurred intergranular creep fracture. The results shows that main mechanism on waterwall tube failure is physical and mechanical factor on reheater tube.
Jurnal ini menjelaskan tentang perhitungan cooling capacity yang dibutuhkan pada Kapal Tanker 17500 LTDW, perhitungan cooling capacity bertujuan untuk mengetahui daya compressor yang dibutuhkan pada system pendingin. Metode yang digunakan adalah menghitung cooling capacity berdasarkan GA (General Arranggement) yang mencakup beberapa parameter yaitu jumlah orang, jumlah jendela, volume ruangan, equipment, dan panas dari lampu. Sehingga didapatkan perhitungan Heat Calculation, Air Capacity, dan Cooling capacity pada sebuah kapal tanker. Hasil penelitian ini menunjukkan bahwa cooling capacity kapal Tanker 17500 LTDW sebesar 487,87 kW.
Masterplan Percepatan dan Perluasan Pembangunan Ekonomi Indonesia berupa pembangunan infrastruktur jalan tol sepanjang 1334 km membutuhkan semen sebesar 4 juta ton. Melihat total kebutuhan semen menjadikan pabrik semen memiliki peran besar dalam mensukseskan mega proyek yang sedang dilakukan. Kegiatan produksi merupakan salah satu hal yang diperhitungkan sehingga kesiapan peralatan untuk operasional harus dilakukan sesuai dengan tahap perencanaan. Agar tahapan tersebut dapat berjalan dengan baik diperlukan proses pemeliharaan dan perawatan secara berkala. Pemeliharaan pada peralatan produksi semen mesin kiln merupakan salah satu bagian yang utama karena di dalam kiln terjadi semua proses kimia pembentukan klinker dari bahan baku untuk pembuatan (raw mix). Perawatan dilkukan pada komponen drag bucket (pan conveyor) yang berfungsi untuk membawa klinker dari cooler menuju dum clinker. Tahapan yang dilakukan untuk mendapatkan data adalah dengan melakukan observasi di lapangan. Observasi dilakukan dengan terjun langsung melalui proses pengamatan pada peralatan yang dianalisa. Tahap kedua adalah mengumpulkan data yang berupa melakukan pencatatan terhadap proses normalisasi dan maintenance. Tahap ketiga adalah analisis data yang menggunakan metode deskriptif kualitatif. Hasil yang didapatkan dengan proses adjusment sebesar 0.3 sehingga mempengaruhi axial load dari 8 bar mengalami kenaikan 24 bar, sedangkan pada tyre 2 dari 53 bar mengalami penurunan menjadi 36 bar. Proses maintenace pada drag bucket (pan conveyor) menjadikan kerja drag bucket dapat berjalan baik dengan identifikasi dari beberapa parameter diantaranya;pengangkutan material berjalan dengan sempurna karena tidak ada gangguan dari roda drag bucket , masa pakai atau life time komponen roda drag bucket lebih terjaga dan tidak menimbulkan kerusakan pada komponen lain.
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