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"Die soldering terjadi ketika lelehan alumunium menempel ke permukaan material cetakan dan tetap tertinggal setelah pengeluaran produk cor, yang berakibat pada peningkatan biaya produksi dan kehilangan produksi pada industri pengecoran. Perlakuan permukaan seperti nitridisasi dianggap sebagai cara yang efektif dalam menahan terjadinya reaksi soldering. Pada penelitian ini, baja perkakas H13 dengan tiga perlakuan permukaan berbeda dicelup ke dalam lelehan alumunium ADC12 pada temperatur 680°C dan di tahan selama 30 detik, 30 menit, 2 jam, dan 5 jam.Karakterisasi permukaan baja difokuskan pada struktur mikro, distribusi kekerasan, komposisi kimia, kekasaran permukaan, dan kehilangan berat dari baja perkakas H13. Hasilnya ditemukan bahwa shot peening sebelum nitridisasi menghasilkan kekerasan permukaan dan kedalaman lapisan nitrida yang lebih tinggi, yaitu 1033 HV (68 HRC) dan 105 µm, dibanding dengan perlakuan nitridisasi saja, 1033 HV (68 HRC) dan 105 µm.Hasil pernelitian ini juga menunjukkan bahwa perlakuan permukaan yang berbeda memberikan morfologi permukaan yang berbeda, dimana perlakuan shot peening saja menghasilkan kecenderungan soldering yang disertai pembentukan lapisan intermetalik; namun soldering tidak ditemukan pada permukaan dengan perlakuan nitridisasi dan shot peening yang dilanjut dengan nitridisasi.

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Die soldering occurs when molten aluminum sticks to the surface of a die material and remains there after the ejection of the part. This resulted in low productivity and economic value in the foundry industry. Nitriding surface treatment is considered as an effective way to prevent soldering. In this research, H13 tool steel with three different surface treatments were dipped into the molten of ADC12 at temperature 680°C and held for 30 seconds, 30 minutes, 2 hours, and 5 hours.

Characterizations on the surface of the steel were focused on the microstructure, microhardness profile, chemical composition, surface roughness, and weight loss of the H13 tool steel. It was found that shot peening prior to nitriding gives a higher surface hardness and depth of nitride layer of H13 tool steel, 114 HV (>70 HRC) and 120.5 µm, than the nitriding only process, 1033 HV (68 HRC) and 105 µm.

The research results also showed that different surface treatment produced different morphologies of the steel surface in which the shot peening only treatment showed a soldering tendency with the present of intermetallic layer; while the soldering was not found on the nitrided and shot peened - nitrided sample."

"[ABSTRAKPada proses pembentukan logam metode die casting, nitridisasi memegangperanan penting dalam peningkatan umur pakai dies. Inovasi proses perlakuanpermukaan yang dilakukan sebelum nitridisasi bertujuan untuk meningkatkan efisiensi nitridisasi dan kedalaman lapisan nitrida pada baja H13 Modifikasi.Nitridisasi gas dilakukan dalam vacuum furnace, pada suhu 510oC selama 5 jam.Shot peening dilakukan dengan menggunakan bola baja dengan tekanan 461 kPa.Shot blasting dilakukan sebagai metode pembersihan permukaan material menggunakan partikel SiC. Karakterisasi permukaan sampel sebelum dan sesudahvariasi proses difokuskan pada perubahan struktur mikro, distribusi kekerasanmikro, dan komposisi kimia lapisan nitridisasi. Dari proses nitridisasi yangdidahului shot peening, didapatkan kekerasan maksimal 1196 HV dengan kedalaman efektif lapisan difusi 72 !m. Nilai ini lebih besar dari proses nitridisasitanpa didahului perlakuan permukaan, yang menghasilkan kekerasan maksimal 1101,4 HV dengan kedalaman efektif lapisan difusi 54!!m. Variasi proses nitridisasi dengan shot peening menghasilkan ketebalan white layer 4,1!!m; lebih tebal dari proses nitridisasi tanpa shot peening 3,7!!m. Sedangkan pada nitridisasiyang tidak didahului perlakuan permukaan tidak ditemukan adanya white layer.ABSTRAKIn the die casting practice, nitriding represents an important factor in enhancingthe service life of dies. Surface treatment innovation prior to nitriding in thisresearch aim to increased the nitriding efficiency and the depth of nitrided layer ofH13 Modification steel. The gas nitriding process was performed at temperature510oC for 5 hours in a vacuum furnace. Shot peening was performed prior tonitriding using a cast steel ball with 461 kPa nozzle pressure. Shot blasting withSiC particle was also performed as a surface cleaning method. Characterizationson the surface of steel were done before and after the variation of nitriding processwith focused on the microstructure, microhardness profile, and the chemicalcomposition of the nitrided layer formed. It was found that shot peening prior tonitriding significantly increased the nitriding kinetics, that results in 1196 HVmaximum surface hardness with 72 !m effective case depth. This results werehigher than the nitriding process without prior surface preparation, which haveonly 1101,4 HV maximum surface hardness with 54!!m effective case depth.While the nitrided only process did not formed a white layer, the shot peenedsample was found to have a white layer with 3,7!!m thick., In the die casting practice, nitriding represents an important factor in enhancingthe service life of dies. Surface treatment innovation prior to nitriding in thisresearch aim to increased the nitriding efficiency and the depth of nitrided layer ofH13 Modification steel. The gas nitriding process was performed at temperature510oC for 5 hours in a vacuum furnace. Shot peening was performed prior tonitriding using a cast steel ball with 461 kPa nozzle pressure. Shot blasting withSiC particle was also performed as a surface cleaning method. Characterizationson the surface of steel were done before and after the variation of nitriding processwith focused on the microstructure, microhardness profile, and the chemicalcomposition of the nitrided layer formed. It was found that shot peening prior tonitriding significantly increased the nitriding kinetics, that results in 1196 HVmaximum surface hardness with 72 !m effective case depth. This results werehigher than the nitriding process without prior surface preparation, which haveonly 1101,4 HV maximum surface hardness with 54!!m effective case depth.While the nitrided only process did not formed a white layer, the shot peenedsample was found to have a white layer with 3,7!!m thick.]"