KARAKTERISTIK SIFAT FISIS DAN MEKANIS MATERIALSTAINLESS STEEL 316L AKIBAT VARIASI DURASI SHOTPEENING 12 BAR DIKOMBINASIKAN DENGANNITRIDASIPLASMA 100 MENIT

Shidiq Indra Wijaya, Ir. Priyo Tri Iswanto, S.T., M.Sc., Ph.D., IPM., ASEAN Eng.

2025 | Skripsi | TEKNIK MESIN

Dalam bidang biomedis, stainless steel 316L banyak digunakan sebagai material implan karena ketahanan korosi dan biokompatibilitasnya yang baik. Namun, sifat mekanik dan ketahanan ausnya masih terbatas, terutama untukpenggunaan jangka panjang di lingkungan biologis. Oleh karena itu, diperlukanmodifikasi permukaan untuk meningkatkan performa material. Penelitianini bertujuan untuk mengetahui pengaruh variasi waktu shot peening terhadapkarakteristik sifat fisis dan mekanis stainless steel 316L yang telah mengalami proses nitridasi plasma. Proses shot peening dilakukan pada tekanan 12 bar dengan variasi waktu0, 10, 20, 30, 45, dan 60 menit, menggunakan bola baja berdiameter 0,6mmdengan kekerasan 45 HRc. Spesimen kemudian dikombinasikan dengan prosesnitridasi plasma pada suhu 400 °C selama 100 menit. Karakterisasi meliputi pengujian sudut kontak (wettability), kekasaran permukaan, kekerasan mikroVickers, dan pengamatan struktur mikro. Hasil penelitian menunjukkan bahwa kombinasi shot peeningdannitridasi plasma menurunkan sudut kontak hingga 63,90°, yang menandakanpeningkatan sifat hidrofilik permukaan. Nilai kekasaran maksimumtercapai pada2,078 ?m pada durasi 10 menit, sedangkan kekerasan tertinggi mencapai 508,64HV pada durasi 60 menit, lebih tinggi dibandingkan perlakuan shot peeningtunggal sebesar 394,10 HV. Struktur mikro menunjukkan pengecilan ukuranbutir, peningkatan densitas dislokasi, serta terbentuknya lapisan nitrida tipe expandedaustenite (S-phase) hingga kedalaman 182,29 ?m.

In the biomedical field, stainless steel 316L is widely used as an implant material due to its excellent corrosion resistance and biocompatibility. However, its mechanical strength and wear resistance remain limited, especially for longterm applications in biological environments. Therefore, surface modificationisrequired to enhance its performance. This study aims to investigate the ef ect of shot peening duration on the physical and mechanical characteristics of stainless steel 316L subjected to plasma nitriding. The shot peening process was carried out at a pressure of 12 bar withtreatment durations of 0, 10, 20, 30, 45, and 60 minutes, using steel balls withadiameter of 0.6 mm and a hardness of 45 HRc. The specimens were subsequentlytreated with plasma nitriding at 400 °C for 100 minutes. Characterizationincluded contact angle (wettability) testing, surface roughness measurement, Vickers microhardness testing, and microstructural observation. The results showed that the combination of shot peening and plasmanitriding reduced the contact angle to 63,90°, indicating improved surfacehydrophilicity. The maximum surface roughness of 2.078 ?m was obtainedat 10minutes, while the highest hardness of 508.64 HV was achieved at 60 minutes, higher than that of single shot peening (394.10 HV). Microstructural analysisrevealed grain refinement, increased dislocation density, and the formationof anexpanded austenite (S-phase) layer extending to a depth of approximately 182.29?m.

Kata Kunci : stainless steel 316L, shot peening , plasma nitriding, wettability, roughness, hardness, microstructure