Sihombing, Meikel Argus Paidotua (2026) Studi Pengaruh Heat Input Dan Multiple Repair Smaw Terhadap Struktur Mikro Material, Sifat Mekanik, Dan Ketahanan Korosi Pada Sambungan Las Similar Dan Dissimilar SCR TEN 2–SS316L. Masters thesis, intitut Teknologi Sepuluh Nopember.
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Abstract
Penelitian ini menganalisis pengaruh variasi heat input dan multiple repair welding menggunakan proses Shielded Metal Arc Welding terhadap struktur mikro, evolusi fasa, kekerasan, dan ketahanan korosi sambungan similar SCR TEN 2–SCR TEN 2 dengan elektroda E8018-W2 serta sambungan dissimilar SCR TEN 2–SS316L dengan elektroda E309L-16 untuk aplikasi chimney liner pada lingkungan sulfuric acid dew point corrosion. Pengelasan dilakukan pada kondisi low heat input dan high heat input hingga tiga siklus repair. Karakterisasi meliputi pengamatan struktur makro dan mikro, X-ray diffraction, perhitungan fraksi ferit, SEM-EDS, uji kekerasan Vickers, uji tarik, polarisasi potensiodinamik, voltametri siklik, serta uji imersi ASTM G31 dalam larutan H₂SO₄ 20% selama 6 jam. Hasil menunjukkan repair welding berulang mengubah keseimbangan fasa dan meningkatkan heterogenitas mikrostruktur. Pada sambungan similar, fasa α-Fe meningkat dari 51% pada Original Weld menjadi 85–87% pada LHI-R1 dan LHI-R2 dengan kekerasan tertinggi 242,2 HV, sedangkan pada sambungan dissimilar fasa kaya Cr-Ni meningkat hingga 37% pada HHI-R2 dengan kekerasan tertinggi 298,1 HV. Sambungan dissimilar menunjukkan laju korosi imersi lebih tinggi (9,37–27,28 mmpy) dibandingkan similar (2,78–7,07 mmpy), dengan LHI-R2 paling kritis. Tingginya laju korosi ini disebabkan oleh heterogenitas komposisi dan fasa sambungan dissimilar yang menimbulkan korosi galvanik. Pada skala makro, SCR TEN 2 bersifat anodik terhadap SS316L, sedangkan pada skala mikro, dilusi menghasilkan sebaran fasa kaya Cr-Ni yang tidak merata pada logam las, sehingga bagian dengan kandungan paduan lebih rendah terkorosi lebih dahulu dalam H₂SO₄. Secara keseluruhan, HHI-R1 direkomendasikan untuk sambungan dissimilar dan LHI-R1 untuk sambungan similar karena memberikan keseimbangan terbaik antara mikrostruktur, sifat mekanik, dan ketahanan korosi.
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This study analyzed the effect of heat input variation and multiple repair welding using the Shielded Metal Arc Welding process on the microstructure, phase evolution, hardness, and corrosion resistance of similar SCR TEN 2–SCR TEN 2 joints welded with E8018-W2 electrodes and dissimilar SCR TEN 2–SS316L joints welded with E309L-16 electrodes for chimney liner applications in sulfuric acid dew point corrosion environments. Welding was performed under low heat input and high heat input conditions with up to three repair cycles. Characterization was carried out through macrostructure and microstructure observation, X-ray diffraction, ferrite fraction calculation, SEM-EDS, Vickers hardness testing, tensile testing, potentiodynamic polarization, cyclic voltammetry, and ASTM G31 immersion testing in 20% H₂SO₄ solution for 6 hours. The results showed that repeated repair welding altered the phase balance and increased microstructural heterogeneity. In the similar joints, the α-Fe phase increased from 51% in the Original Weld to 85–87% in LHI-R1 and LHI-R2, with the highest hardness of 242.2 HV, while in the dissimilar joints, the Cr-Ni-rich phase increased up to 37% in HHI-R2, with the highest hardness of 298.1 HV. The dissimilar joints exhibited higher immersion corrosion rates (9.37–27.28 mmpy) than the similar joints (2.78–7.07 mmpy), with LHI-R2 being the most critical condition. This higher corrosion rate was attributed to the compositional and phase heterogeneity of the dissimilar joints, which induced galvanic corrosion. At the macro scale, SCR TEN 2 was anodic to SS316L, while at the micro scale, dilution produced an uneven distribution of Cr-Ni-rich phases in the weld metal, causing regions with lower alloy content to corrode preferentially in H₂SO₄. Overall, HHI-R1 is recommended for dissimilar joints and LHI-R1 for similar joints, as they provide the best balance of microstructure, mechanical properties, and corrosion resistance.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Heat Input, Multiple Repair Welding, SMAW, Sambungan Dissimilar SCR TEN 2–SS316L, Korosi Galvanik, Korosi Titik Embun Asam Sulfat Heat Input, Multiple Repair Welding, SMAW, SCR TEN 2–SS316L, Sulfuric Acid Dew Point Corrosion, Galvanic Corrosion,Low Alloy Corrosion-Resistant Steel |
| Subjects: | T Technology > TS Manufactures T Technology > TS Manufactures > TS227 Welding. |
| Divisions: | Faculty of Industrial Technology > Material & Metallurgical Engineering > 27101-(S2) Master Thesis |
| Depositing User: | Meikel Argus Paidotua Sihombing |
| Date Deposited: | 21 Jul 2026 01:44 |
| Last Modified: | 21 Jul 2026 01:44 |
| URI: | http://repository.its.ac.id/id/eprint/135939 |
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