Oktaviani, Risma (2026) Analisis Pengaruh Variasi Filler Metal 308L dan 316L serta Arus Pengelasan terhadap Karakteristik Mikrostruktur dan Distribusi Kekerasan Sambungan Las Kombinasi GTAW+SMAW pada Baja Tahan Karat AISI 304L. Other thesis, Institut Teknologi Sepuluh Nopember.
![[thumbnail of 5011221010-Undergraduate_Thesis.pdf]](http://repository.its.ac.id/style/images/fileicons/text.png) |
Text
5011221010-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (40MB) | Request a copy |
Abstract
Baja tahan karat austenitik AISI 304L banyak digunakan dalam industri fabrikasi logam dan konstruksi pipa karena kombinasi ketahanan korosi dan kemampuan las yang baik. Pada praktik di lapangan, substitusi filler metal ER316L/E316L sebagai pengganti ER308L/E308L sering dilakukan berdasarkan pertimbangan praktis, sementara data metalurgi yang spesifik untuk kombinasi proses GTAW+SMAW dengan variasi arus masih terbatas. Penelitian ini bertujuan menganalisis pengaruh perbedaan komposisi kimia filler 308L dan 316L terhadap prediksi mikrostruktur berdasarkan diagram Schaeffler, pengaruh variasi arus terhadap karakteristik mikrostruktur weld metal, serta perbedaan distribusi kekerasan pada zona weld metal, HAZ, dan base metal. Pengujian dilakukan melalui analisis komposisi kimia menggunakan OES dan PMA, pengamatan metalografi, plotting diagram Schaeffler berbasis data OES aktual, serta pengujian kekerasan Vickers pada tiga variasi arus (85A, 105A, dan 125A). Hasil penelitian menunjukkan weld metal 308L menghasilkan Creq/Nieq sebesar 1,68 pada mode solidifikasi FA dengan fraksi ferrite 6% dan morfologi dominan lathy ferrite, sedangkan weld metal 316L menghasilkan Creq/Nieq sebesar 1,47 pada mode solidifikasi AF dengan fraksi ferrite 4% dan morfologi seragam skeletal ferrite. Peningkatan arus dari 85A ke 125A secara konsisten menghasilkan morfologi ferrite delta yang semakin kasar pada kedua filler. Filler 316L menghasilkan kekerasan lebih tinggi dibandingkan 308L akibat efek solid solution strengthening molibdenum, namun kandungan Mo yang jauh lebih tinggi dari base metal 304L berpotensi menciptakan ketidakselarasan komposisi di zona transisi. Berdasarkan hasil tersebut, filler 308L direkomendasikan untuk aplikasi yang mengutamakan keselarasan komposisi dengan base metal, sedangkan filler 316L direkomendasikan untuk aplikasi yang membutuhkan kekerasan sambungan las lebih tinggi. Pada kedua filler, arus 85A dapat dipertimbangkan apabila kualitas mikrostruktur menjadi prioritas utama dalam prosedur pengelasan AISI 304L di industri fabrikasi.
===================================================================================================================================
Austenitic stainless steel AISI 304L is widely used in metal fabrication industries, pipeline construction, and industrial process equipment due to its excellent combination of corrosion resistance and weldability. In field practice, the substitution of ER316L/E316L filler metal in place of ER308L/E308L for welding 304L base metal is commonly performed basemicrostructuralconsiderations, while metallurgical data specifically addressing the GTAW+SMAW combined process with current variation under these conditions remains limited as a comprehensive technical basis. This study aims to analyze the effect of chemical composition differences between filler metals 308L and 316L on weld metal microstructure prediction based on the Schaeffler diagram, the effect of welding current variation on weld metal microstructural characteristics, and hardness distribution differences across the weld metal, HAZ, and base metal zones. Testing was conducted through chemical composition analysis using Optical Emission Spectrometry (OES) and Positive Material Identification (PMA), metallographic examination, Schaeffler diagram plotting based on actual OES data, and Vickers hardness testing at three welding current variations (85A, 105A, and 125A). Results show that weld metal 308L produced a Creq/Nieq ratio of 1.68 in FA solidification mode with 6% ferrite fraction and dominant lathy ferrite morphology, while weld metal 316L produced a Creq/Nieq ratio of 1.47 in AF solidification mode with 4% ferrite fraction and uniform skeletal ferrite morphology across all current variations. Increasing welding current from 85A to 125A consistently produced coarser delta ferrite morphology in both fillers. Filler 316L produced higher weld metal hardness than 308L across all current variations due to the solid solution strengthening effect of molybdenum, however its significantly higher Mo content compared to 304L base metal potentially creates compositional mismatch at the transition zone. Based on these findings, filler 308L is recommended for AISI 304L welding applications that prioritize weld metal compositional compatibility with the base metal, while filler 316L is recommended for applications requiring higher weld joint hardness. For both fillers, a welding current of 85A produces the finest and most densely distributed delta ferrite morphology and may be considered when microstructural quality is the primary priority in AISI 304L welding procedures in fabrication industries.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | AISI 304L, filler metal 308L, filler metal 316L, GTAW, SMAW AISI 304L, GTAW, SMAW, filler metal 308L, filler metal 316L |
| Subjects: | T Technology > TS Manufactures > TS227 Welding. |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis |
| Depositing User: | Risma Oktaviani |
| Date Deposited: | 24 Jul 2026 01:24 |
| Last Modified: | 24 Jul 2026 01:24 |
| URI: | http://repository.its.ac.id/id/eprint/135232 |
Actions (login required)
 |
View Item |