Hutajulu, Romonang (2025) Analisis Pengaruh Pengelasan Berulang Terhadap Evolusi Strukture Mikro, Sifat Mekanik Dan Laju Korosi Baja Tahan Karat Duplex UNS S32205. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Siklus panas yang tidak terkontrol pada proses pengelasan berulang Duplex Stainless Steel (DSS) akan mempengaruhi keseimbangan fasa ferit (), fasa austenit () dan terbentuknya fasa lainnya seperti fasa sigma (σ), Chi () dan yang lainnya. Akibat dari ketidak seimbangan ini akan menghasilkan perubahan sifat mekanik dan ketahanan korosi dari hasil akhir lasan. Tesis ini menyelidiki secara komprehensif dampak pengelasan berulang pada mikrostruktur, sifat mekanik, dan ketahanan korosi duplex stainless steel UNS 32205. Tujuh sampel di las dengan proses pengelasan gas tungsten arc welding (GTAW). Sampel pertama disiapkan sebagai original weld (OW), kemudian daerah lasan di preparasi kembali pada area yang sama yang selanjutnya di lakukan pengelasan kembali dengan variasi masukan panas, yaitu masukan panas rendah dan tinggi. Sampel repair pertama diberi identifikasi LHI-R1 & HHI-R1 kemudian proses repair kedua dan ketiga di lakukan sama dengan proses repair pertama dengan identifikasi LHI-R2 & HH1-R2 dan LHI-R3 & HH1-R3. Sampel ini kemudian dianalisa untuk mempelajari perubahan strukture mikro, sifat mekanik dan laju korosi hasil lasan. Pengujian kekerasan dilakukan untuk mengetahui sifat mekanik hasil penyambungan, struktur mikro diteliti menggunakan mikroskopik optic, jumlah kandungan ferit dihitung dengan menggunakan metoda manual, morfologi atau struktur dari pengelasan diteliti dengan menggunakan Scanning Electron Microcope (SEM), struktur kristal di analisa dengan menggunakan X-Ray Diffraction (XRD), karakterisitik kimia dari pengelasan di analisa dengan menggunakan Energy Dispersive X-Ray (EDX) dan dalam hal ketahanan korosi pengujian yang dilakukan adalah Cyclcic Voltammetry dan potensiodinamik. Hasil penelitian proses pengelasan berulang menunjukkan terjadinya perubahan yang signifikan terhadap sifat mekanik, struktur mikro, jumlah ferit dan laju korosi. Ukuran butir pada HAZ sampel HHI cenderung lebih besar dibandingkan dengan LHI dan Jumlah ferit pada daerah HAZ LHI-R2 cenderung tinggi yaitu sekitar 68%. Nilai Kekerasan cenderung meningkat didareah HAZ yaitu nilai maksimum 295 HV. Sedangkan untuk laju korosi cenderung meningkat dengan meningkatnya pengelasan berulang.
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Uncontrolled heat cycles on the repeated welding process of Duplex Stainless Steel (DSS) will affect the balance of the ferrite phase (), austenite phase () and the formation of other phases such as sigma (σ), Chi () and Chromium Nitride (CrN) phases. The result of this imbalance will result in changes in the mechanical properties and corrosion resistance of the final weld. This thesis comprehensively investigates the impact of repeated welding on the microstructure, mechanical properties, and corrosion resistance of duplex stainless steel UNS 32205. Seven samples were welded using the gas tungsten arc welding (GTAW) welding process. The first sample is prepared as an original weld (OW), then the weld area is reprepared in the same area which is then welded again with variations in heat input, namely low and high heat input. The first repair sample was identified R1-LHI & R1-HHI then the second and third repair processes were carried out the same as the first repair process with the identification R2-LHI & R2 HH1 and R3-LHI & R3 HH1. This sample is then analyzed to study changes in microstructure, mechanical properties and corrosion rate of the weld results. Hardness testing was carried out to determine the mechanical properties of the joining results, the microstructure was examined using optical microscopy, the amount of ferrite content was calculated using manual methods, the morphology or structure of the weld was examined using a Scanning Electron Microscope (SEM), the crystal structure was analyzed using X-Ray Diffraction (XRD), the chemical characteristics of welding are analyzed using Energy Dispersive X-Ray (EDX) and in terms of corrosion resistance the tests carried out are Cyclic Voltammetry and Potentiodynamic. The research results of the repeated welding process showed significant changes in the mechanical properties, microstructure, amount of ferrite and corrosion rate. The grain size in the HAZ of the HHI sample tends to be larger compared to the LHI and the amount of ferrite in the LHI-R2 HAZ tends to be high, namely around 68%. The hardness value tends to increase in the HAZ area, namely the maximum value is 295 HV. Meanwhile, the corrosion rate tends to increase with increasing repeated welding.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | DSS, pengelasan berulang, mikrostruture, sifat mekanik, korosi, repeated welding, microstructure, mechanical properties, corrosion. |
| Subjects: | T Technology > TN Mining engineering. Metallurgy > TN879.6 Welding |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 27101-(S2) Master Thesis |
| Depositing User: | Romonang Hutajulu |
| Date Deposited: | 31 Jan 2025 02:20 |
| Last Modified: | 31 Jan 2025 02:20 |
| URI: | http://repository.its.ac.id/id/eprint/117204 |
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