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Karakteristik Sifat Mekanik Baja Laterit Melalui Proses Pengerjaan dan Perlakuan Panas Bintang Adjiantoro; Adil Jamali; Rahardjo Binudi; Muhammad Yunan Hasbi
Jurnal Teknologi Bahan dan Barang Teknik Vol 6, No 2 (2016)
Publisher : Balai Besar Bahan dan Barang Teknik

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (773.49 KB) | DOI: 10.37209/jtbbt.v6i2.72

Abstract

Steel laterite potentially meet the national infrastructure demand that requires toughness properties because of Ni content is about 2-3%. In this study, there were five types composition of the as-cast steel laterite from decarburises Nickel Pig Iron (NPI) process. Five types of compositions as-cast steel were prepared for homogenizing process at 900 °C and subsequently hot rolled into the size 6,5 mm thick from 40 mm. Hot rolled process conducted at 980 °C with three stages of reduction. The first stage was 60%, 40% the second and last stage was 30%. Samples subsequently cooled in the air and prepared for hardness test and tensile test. Results of hot rolled process showed that the formability of steel laterite quite well with no crack during hot rolled. Increased mechanical properties of steel promoted by hot rolled process with optimum results 238,5 HB and 779 N/mm2 respectively. Metallography observation obtained show that Ni was promoted grain refining on recrystallization phenomena.Baja berbasis bijih nikel laterit berpotensi diaplikasikan dalam infrastruktur yang membutuhkan sifat tangguh karena kandungan Ni yang dimiliki yaitu sebesar 2-3%. Dalam studi ini telah dilakukan penelitian mengenai sifat mekanik terhadap lima jenis komposisi as-cast baja laterit hasil proses dekarburisasi Nickel Pig Iron (NPI).  Baja laterit hasil as-cast dengan  lima jenis komposisi terlebih dahulu dilakukan homogenisasi dengan proses anil pada suhu 900 °C. Spesimen baja kemudian dilakukan pengerolan panas hingga menjadi pelat dengan ketebalan 6 mm dari tebal awal 40 mm. Proses pengerolan dilakukan pada suhu 980 °C dengan tiga tahap reduksi yaitu 60%, 40% dan 30%. Setelah proses pengerolan panas dilakukan, pelat didinginkan di udara dan kemudian dilakukan uji kekerasan dan uji tarik. Hasil penelitian menunjukkan bahwa mampu bentuk baja laterit cukup baik dengan tidak ditunjukkannya keretakan pada sampel. Hasil uji kekerasan dan uji tarik juga menunjukkan kecenderungan peningkatan pada tiap sampel baja dengan nilai optimal mencapai 238,5 HB dan 779 N/mm2. Ditinjau dari pengamatan struktur mikro, paduan Ni memicu penghalusan butir dalam fenomena rekristalisasi.
Nichrome Dependency in Welding Layer Using In situ Fabrication on Hardness and Corrosion Properties Syaripuddin; Sopiyan; Muhammad Fauzan Perdana Putra; Maman Kartaman Ajiriyanto; Sigit Dwi Yudanto; Muhammad Yunan Hasbi; Susetyo, Ferry Budhi
Science and Technology Indonesia Vol. 9 No. 3 (2024): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.3.651-659

Abstract

The use of shielded metal arc welding (SMAW) equipment to synthesize alloys is one of the most promising methods as it can be used for in-situ fabrication. The hardness and corrosion properties of the deposited layer during the welding process can be enhanced by dilution of nichrome (NiCr) during the process. Therefore, the alloy was synthesized on the surface of the mild steel using SMAW equipment with various NiCr additions. The properties of the alloy were investigated using an X-ray diffraction (XRD), an Optical microscope, a Potentiostat, and a Vickers hardness apparatus. The appearance of martensite overlaps with the ferrite phase could be affected by the addition of NiCr to the alloy. An increase in NiCr content is followed by an increase in the lattice parameter value of the ferrite phase. The presence of a certain amount of nickel (Ni) contributes to the formation of lower transformation phases, including martensite. At the same time, the incorporation of chromium (Cr) also plays a significant role in promoting the formation of acicular ferrite. An increase in NiCr content in NiCr2 and NiCr3 samples results in a quantitative increase in martensite formation. Adding 0.434 g of NiCr to the weld deposited layer could result in the corrosion rate of the alloy being 0.1118 mm/y. Higher hardness is found in the NiCr3 sample, around 742.06 HV.
PENGARUH TITANIUM DALAM LAPISAN LAS TERHADAP STRUKTUR MAKRO-MIKRO, KEKERASAN, DAN LAJU KOROSI: Titanium Effect in Weld Layer on The Macro-microstructure, Hardness, and Corrosion Rate Sopiyan; Syaripuddin; Muhammad Hafidz Fatahillah; Muhammad Fauzan Perdana Putra; Muhammad Yunan Hasbi
Jurnal Konversi Energi dan Manufaktur Vol. 9 No. 2 (2024)
Publisher : Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/JKEM.9.2.2

Abstract

Low carbon steel cannot be hardened because of its low carbon content. Therefore, a hardfacing process is carried out to increase hardness. Apart from increasing hardness, the benefits of hardfacing can increase wear and corrosion resistance. The hardfacing process using the shielded metal arc welding (SMAW) process generally uses commercial electrodes. Therefore, it is necessary to add other elements such as titanium (Ti) to the weld layer to further increase its hardness. This research aims to study the influences of Titanium (Ti) addition in welding layers that were welded using HV 600 to micro and macrostructure, hardness, and corrosion rate. The hardfacing was conducted using the SMAW process with the various addition of Ti (0.115, 0.223, and 0.334 g) and cooled at room temperature. Macrostructure and microstructure were investigated using digital cameras and an optical microscope. Hardness and corrosion rate were investigated using the Vickers hardness test and weigh loss method. Based on macrostructure investigation, there is a perfect fusion between base metal and weld metal. The microstructure formed is a austenite, martensite and carbide phase. The lowest corrosion rate of 17.54 mpy was seen in the Ti1 sample. The lowest Ti addition would resulting higher hardness at 761.06 VHN.