Analisa Pengaruh Temperatur Dan Waktu Tahan NH3 Nitriding Terhadap Struktur Mikro Dan Sifat Mekanik Pada Material Stainless Steel 316 L

Lokawibana, Rakha (2026) Analisa Pengaruh Temperatur Dan Waktu Tahan NH3 Nitriding Terhadap Struktur Mikro Dan Sifat Mekanik Pada Material Stainless Steel 316 L. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Stainless steel 316L banyak digunakan pada komponen industri seperti plunger pump karena memiliki ketahanan korosi yang baik, namun kekerasan permukaannya relatif rendah sehingga rentan mengalami keausan akibat kontak gesek berulang. Penelitian ini bertujuan menganalisis pengaruh temperatur dan waktu tahan proses NH₃ gas nitriding terhadap struktur mikro dan sifat mekanik stainless steel 316L. Proses nitriding dilakukan pada variasi temperatur 450°C, 500°C, dan 550°C dengan waktu tahan 10 dan 20 menit. Karakterisasi dilakukan melalui pengujian metalografi untuk mengamati struktur mikro dan ketebalan case depth, X-Ray Diffraction (XRD) untuk mengidentifikasi fasa yang terbentuk, SEM-Mapping untuk mengamati persebaran unsur Fe, Cr, dan N, serta uji Microhardness Vickers untuk mengetahui perubahan kekerasan permukaan. Hasil metalografi menunjukkan terbentuknya lapisan difusi nitrogen pada permukaan material setelah proses nitriding. Pada waktu tahan 10 menit, case depth meningkat dari 26,85 µm pada 450°C menjadi 43,49 µm pada 500°C dan 65,20 µm pada 550°C. Pada waktu tahan 20 menit, case depth meningkat dari 54,81 µm pada 450°C menjadi 60,56 µm pada 500°C dan 80,58 µm pada 550°C. Hasil XRD menunjukkan indikasi terbentuknya S-Phase/expanded austenite sebagai fasa utama dengan kemungkinan terbentuknya Fe₃N. Pembentukan fasa tersebut berkaitan dengan masuknya nitrogen secara interstisial ke dalam kisi austenit dan pembentukan nitrida besi, sehingga meningkatkan kekerasan permukaan. Nilai kekerasan meningkat dari 245,6 HV pada material tanpa perlakuan menjadi 904,1–998,9 HV pada waktu tahan 10 menit dan 994,3–1203 HV pada waktu tahan 20 menit. SEM-Mapping menunjukkan Fe dan Cr tersebar merata, sedangkan N tidak tampak dominan karena keterbatasan deteksi unsur ringan. Secara keseluruhan, peningkatan temperatur dan waktu tahan NH₃ gas nitriding meningkatkan case depth dan kekerasan permukaan SS316L. Kondisi optimum pada penelitian ini diperoleh pada temperatur 550°C dengan waktu tahan 20 menit, karena menghasilkan lapisan difusi paling tebal dan kekerasan tertinggi, meskipun potensi ketidakseragaman lapisan perlu dikendalikan pada penelitian lanjutan melalui kontrol parameter proses yang tepat. =======================================================================================================================================
Stainless steel 316L is widely used in industrial components such as plunger pumps due to its excellent corrosion resistance. However, this material has relatively low surface hardness, making it susceptible to wear caused by repeated sliding contact. This study aims to analyze the effects of temperature and holding time in the NH₃ gas nitriding process on the microstructure and mechanical properties of stainless steel 316L. The nitriding process was carried out at temperature variations of 450°C, 500°C, and 550°C with holding times of 10 and 20 minutes. Material characterization was conducted using metallographic testing to observe microstructural changes and case depth, X-Ray Diffraction (XRD) to identify the formed phases, SEM-Mapping to examine the distribution of Fe, Cr, and N elements, and Vickers microhardness testing to evaluate changes in surface hardness. The metallographic results showed the formation of a nitrogen diffusion layer on the material surface after the nitriding process. At a holding time of 10 minutes, the case depth increased from 26.85 µm at 450°C to 43.49 µm at 500°C and 65.20 µm at 550°C. At a holding time of 20 minutes, the case depth increased from 54.81 µm at 450°C to 60.56 µm at 500°C and 80.58 µm at 550°C. The XRD results indicated the formation of S-Phase or expanded austenite as the main phase, with a possible formation of Fe₃N. These phases are associated with the interstitial diffusion of nitrogen into the austenitic lattice and the formation of iron nitride, which contribute to the improvement of surface hardness. The hardness value increased from 245.6 HV in the untreated material to 904.1–998.9 HV at a holding time of 10 minutes and 994.3–1203 HV at a holding time of 20 minutes. SEM-Mapping showed that Fe and Cr were uniformly distributed, while N did not appear dominant due to the limitation of detecting light elements. Overall, increasing the temperature and holding time of NH₃ gas nitriding increased the case depth and surface hardness of stainless steel 316L. The optimum condition in this study was obtained at 550°C with a holding time of 20 minutes, as it produced the thickest diffusion layer and the highest hardness value, although layer uniformity needs to be further controlled.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Stainless Steel 316L, NH₃ gas nitriding, S-Phase, case depth, kekerasan Vickers, Vickers hardness.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ903 Pumping machinery.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Rakha Lokawibana
Date Deposited:	03 Aug 2026 03:40
Last Modified:	03 Aug 2026 03:40
URI:	http://repository.its.ac.id/id/eprint/138641

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