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Efek Perlakuan Panas Terhadap Sifat Mekanik Logam Stainless Steel Seri J4 Priyotomo, Gadang; Astawa, I Nyoman Gede Putrayasa; Rokhmanto, Fendy
TEKNIK Vol. 42, No. 2 (2021): August 2021
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v42i2.36461

Abstract

Logam stainless steel (SS) seri J4 merupakan baja paduan austenitik krom dan mangan yang mempunyai kekuatan dan ketahanan korosi yang cukup baik. Namun umumnya, logam SS austenitik mengalami proses sensitasi saat terjadi pemanasan logam yang menurunkan sifat mekanik logam. Investigasi pengaruh sifat mekanik SS seri J4 terhadap variasi temperatur logam  dilakukan menggunakan uji tarik dan uji kekerasan mikro Vickers. Proses pemanasan logam dilakukan pada rentang suhu antara 600oC-1050oC. Penurunan nilai kekuatan tarik, kekuatan luluh, dan kekerasan yang disertai kenaikan ketangguhan dan elongasi terjadi seiring dengan kenaikan temperatur logam hingga 1050oC. Ini dimungkinkan akibat transformasi α’-martensite menjadi fasa austenit seiring dengan peningkatan temperatur pemanasan. Disisi lain, Penurunan nilai ketangguhan, kekuatan luluh dan elongasi terjadi pada kisaran temperatur pemanasan 700oC dimana ini mengindikasikan proses sensitasi paduan stainless steel J4 terjadi. Proses sensitasi logam SS akan berhubungan dengan kerentanan korosi retak tegang stainless steel.
LATTICE STRAIN ANALYSIS OF TITANIUM ROD PROCESSED BY EQUAL-CHANNEL ANGULAR PRESSING (ECAP) WITH Bc ROUTE USING X-RAY DIFFRACTION LINE BROADENING ANALYSIS Purawiardi, R. Ibrahim; Astawa, I Nyoman Gede Putrayasa
SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin Vol. 15 No. 1 (2021): SINTEK JURNAL
Publisher : Universitas Muhammadiyah Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24853/sintek.15.1.26-35

Abstract

Equal-channel angular pressing (ECAP) was one of severe plastic deformation method in order to increase the mechanical properties of solid metal without changing its dimension and without adding any alloy elements. The change of mechanical properties on ECAPed metals was caused by the change of lattice strain, so that the lattice strain investigation was recommended for evaluating ECAPed metals. In this study, pure titanium rod was treated by ECAP with Bc route and two passes. Before ECAPed, this titanium rod consisted of two lattice strains i.e. 0.001014 and 0.005241. After ECAPed, a lattice strain of 0.005241 reduces to 0.003205 and 0.003555 after first pass and reduces again to 0.002576 and 0.002647 after two passes. Meanwhile, a lattice strain of 0.001014 was annihilated after ECAP treatment. These results show that ECAP treatment can reduce and eliminate lattice strains on titanium rod. This study also shows that the reduction of lattice strains implicates to the increasing of its hardness value.