Analisis Pengaruh Ukuran Partikel SiC Terhadap Kekerasan Dan Ketahanan Oksidasi Dalam Proses Pelapisan Dengan Metode HVOF

Pada boiler yang menggunakan sistem CFB, Batubara yang sudah diperkecil ukuranya, dimasukkan dan dicampur dengan limestone dan pasir silica. Material bahan bakar tersebut kemudian didorong ke atas oleh udara yang bertekanan tinggi sehingga memudahkan pembakaran. Efek samping dari proses ini adalah terjadinya erosi pada water wall tube boiler dan pertikel erosi juga akan menempel pada water wall tube sehingga terjadi reaksi kimia oxide scale. Jika proses ini di biarkan maka water wall tube boiler akan mengalami penipisan yang pada akhirnya menyebakan kebocoran pada water wall tube. Sehingga dibutuhkan material yang memiliki ketahanan terhadap keausan, abrasi dan oksidasi yang tinggi. Salah satu cara yang dapat dilakukan untuk mengatasi permasalahan pada boiler tube adalah dengan cara pelapisan mengguanakan metode HVOF (high velocity oxygen fuel). Pada penelitian ini pelapisan dilakukan pada tube baja A-192 dengan material pelapis NiCrBSi-30SiC dan variasi ukuran partikel SiC sebesar 50μm dan 37μm. Proses pelapisan dilakukan menggunakan peralaatan HVOF dengan gas pembakaran yang digunakan adalah gas propane (C3H8), gas oksigen (O2) dan gas pengangkut berupa nitrogen (N2). Metode pengujian yang digunakan pada penelitian ini adalah pengamatan struktur mikro, pengujian kekerasan mikro, pengujian siklus termal dan pengujian kekuatan adhesi pelapisan. Dari hasil penelitian ini didapatkan bahwa Nilai kekerasan tertinggi sebesar 782 HV didapat pada specimen dengan ukuran partikel 37µm. Proses pelapisan pada material mampu mengurangi laju oksidasi temperature tinggi jika dibandingkan dengan material tanpa pelapisan. Struktur lapisan NiCrBSi-30SiC dengan ukuran partikel SiC 37 mikron memiliki struktur mikro yang lebih padat jika dibandingkan dengan ukuran partikel SiC yang lebih besar. ================================================================================================ In boilers that use a CFB system, coal which has been reduced in size, is inserted and mixed with limestone and silica sand. The fuel material is then pushed up by high-pressure air to help combustion process. The side effect of this process is the erosion of the boiler water wall tube and erosion particles will also stick to the water wall tube so that a chemical oxide reaction occurs. If this process is allowed, the boiler water wall tube will experience thinning which in turn will cause a leak in the water wall tube. So material is needed that has a high resistance to wear, abrasion and oxidation. One method that can be done to overcome the problems in the boiler tube is by coating using the HVOF (high velocity oxygen fuel) method. In this research, coating was carried out on tube A-192 with NiCrBSi-30SiC coating material and SiC particle size variation of 50μm and 37μm. The coating process is carried out using HVOF devices with combustion gases used are propane gas (C3H8), oxygen gas (O2) and transport gas in the form of nitrogen (N2). The test methods used in this research were microstructure observation, micro hardness testing, thermal cycle testing and coating adhesion strength testing. From the results of this research it was found that the highest hardness value 782 HV was obtained in specimens with smaller particle size. The coating process on the material is able to reduce the high temperature oxidation rate when compared with non-coating material. the microstructure of NiCrBSi-30SiC layer with a particle size of SiC 37 microns has a denser micro structure compared with greater particle size of SiC

Liquefaction potential evaluation on reconstruction project of irrigation canal in the Jono Oge and Lolu Village

In Indonesia's liquefaction history, the province of Central Sulawesi was severely affected in several locations when a 7.5 Mw earthquake occurred in September 2018. This study aims to evaluate the liquefaction potential and generate the liquefaction hazard map in the reconstruction project of the Gumbasa Irrigation Canals passed through Jono Oge Village and Lolu Village, closely related to the liquefaction event in the Sigi Regency area. Using the simplified procedure method by Idriss and Boulanger, the Liquefaction Factor of Safety (FOS) was calculated for each layer of soil from thirteen (13) locations of soil investigation test at the end of 2021 by the Ministry of Public Works and Housing. Furthermore, it was followed by calculating the Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI). The analysis results show that the construction work area has the liquefaction potential with the observed groundwater level. It is mapped on irrigation canals along the Jono Oge Village and Lolu Village to know the critical segment of the irrigation project. Hereafter, an irrigation canal segment named BGKN-45 to BGKN-46 in Jono Oge required a specific mitigation plan to prevent damage from liquefaction in the future

Liquefaction potential evaluation on reconstruction project of irrigation canal in the Jono Oge and Lolu Village

In Indonesia's liquefaction history, the province of Central Sulawesi was severely affected in several locations when a 7.5 Mw earthquake occurred in September 2018. This study aims to evaluate the liquefaction potential and generate the liquefaction hazard map in the reconstruction project of the Gumbasa Irrigation Canals passed through Jono Oge Village and Lolu Village, closely related to the liquefaction event in the Sigi Regency area. Using the simplified procedure method by Idriss and Boulanger, the Liquefaction Factor of Safety (FOS) was calculated for each layer of soil from thirteen (13) locations of soil investigation test at the end of 2021 by the Ministry of Public Works and Housing. Furthermore, it was followed by calculating the Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI). The analysis results show that the construction work area has the liquefaction potential with the observed groundwater level. It is mapped on irrigation canals along the Jono Oge Village and Lolu Village to know the critical segment of the irrigation project. Hereafter, an irrigation canal segment named BGKN-45 to BGKN-46 in Jono Oge required a specific mitigation plan to prevent damage from liquefaction in the future