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All Journal Traksi : Majalah Ilmiah Teknik Mesin Jurnal Pendidikan Teknologi dan Kejuruan Jurnal Sains Materi Indonesia SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin ROTOR: JURNAL ILMIAH TEKNIK MESIN Widyariset Jurnal METTEK (Jurnal Ilmiah Nasional Dalam Bidang Ilmu Teknik Mesin) Science and Technology Indonesia Majalah Ilmiah Material, Komponen dan Konstruksi Jurnal AUDI Jurnal Rekayasa Material, Manufaktur & Energi Indonesian Journal of Chemistry NUSANTARA : Jurnal Ilmu Pengetahuan Sosial Majalah Ilmiah Pengkajian Industri Metalurgi Jurnal Metalurgi dan Material Indonesia Journal of Engineering and Scientific Research (JESR) Piston: Journal of Technical Engineering Widyariset Teknomekanik Indonesian Journal of Engineering and Science (IJES) Journal of Materials Exploration and Findings Malcom: Indonesian Journal of Machine Learning and Computer Science Metalurgi Jurnal Sains Materi Indonesia Recent in Engineering Science and Technology
Rini Riastuti, Rini
Departemen Teknik Metalurgi Dan Material, Fakultas Teknik, Universitas Indonesia, Depok
Aerospace Engineering Astronomy Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Immunology & microbiology Industrial & Manufacturing Engineering Library & Information Science Materials Science & Nanotechnology Mechanical Engineering Neuroscience Physics Transportation

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A STUDY OF STRESS CORROSION CRACKING RESISTANCE FOR COLD FORMING PLASTIC DEFORMED Cu-30Zn ALLOY Gadang Priyotomo; Akhmad Faizal; Rini Riastuti
Widyariset Vol 4, No 1 (2018): Widyariset
Publisher : Pusbindiklat - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1019.12 KB) | DOI: 10.14203/widyariset.4.1.2018.29-36

Abstract

Cu-30Zn alloy has good atmospheric corrosion resistance. It is mainly used as automotive radiator cores, ammunition component, lamp fixture, flashlight shells and kickplates. Cold rolled Cu-30Zn with deformation degree 33,87% at 300OC was tested its Stress Corrosion Cracking (SCC) property. Stress corrosion cracking (SCC) of a Cu–30Zn has been investigated using Mattsson solutions 0,5 M (NH4)2SO4 + 0,05 M CuSO4 in room temperature by using a constant load method. Cu-30Zn has a weakness on stress corrosion cracking in ammonia environment (mattson solution). Scanning electron microscope (SEM) testing indicated the failure of cold roll Cu-30Zn was a transgranular cracking. Furthermore, cracking occued at stress below yield stress. Energy dispersive Spectroscopy (EDS) test exhibited dezincification indication on fracture surface. The visual examination of surface morphology on alloy showed discoloration from yellow to red. Homogenized Cu-30Zn showed better SCC resistance than cold rolled Cu-30Zn.
PERUBAHAN MORFOLOGI STRUKTUR MIKRO PADUAN Cu-Zn 70/30 YANG DILAKUKAN TMCP DI SUHU 300°C Eka Febriyanti; Amin Suhadi; Ayu Rizeki Ridhowati; Rini Riastuti
SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin Vol 11, No 1 (2017): SINTEK JURNAL
Publisher : University of Muhammadiyah Jakarta

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Abstract

Cu-Zn 70/30 alloy are used for various equipment to industry application. However, Cu-Zn 70/30 alloy has a weakness that is susceptible corrosion due to exposure to corrosive environments such as chloride ion (Cl-). Therefore, these characteristics can reduce working efficiency and performance equipment. This research focuses to study about increasing of toughness, corrosion resistance, and surface quality from Cu-Zn 70/30 alloy by conducting Themomechanical Control Process (TMCP). Warm rolling on temperature 300°C is experienced by double pass reversible method with deformation 2x25%, 2x30%, and 2x35%. Warm temperature is temperature between hot and cold work for obtain small grains with a narrow grain boundaries. The result showed that as the increase of deformation degree from 31.6% to be 48.93% causes a decrease diameter grain size, the size of the average grain size decrease from 50.53 μm to be 24.41 μm. This phenomenon is due to partial recrystallization which is indicated by existence of nuclei.
PERUBAHAN MORFOLOGI STRUKTUR MIKRO PADUAN Cu-Zn 70/30 YANG DILAKUKAN TMCP DI SUHU 300°C DENGAN VARIASI WAKTU TAHAN PEMANASAN Eka Febriyanti; Ahmad Fadli; Amin Suhadi; Rini Riastuti
SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin Vol 12, No 1 (2018): SINTEK JURNAL
Publisher : University of Muhammadiyah Jakarta

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Abstract

Cu-Zn alloy (70/30) used extensively for core and tank automotive radiator, ammunition component, and architectural hardware so that susceptible to exposure of corrosive environments such as seawater and ammonia environments. Therefore, this research focuses on the study of mechanical properties and corrosion resistance Cu-Zn 70/30 by implementing warm rolling TMCP method. Thermo-Mechanical Controlled Processing (TMCP) is one method consists of controlled heating and controlled forming to produce high quality materials. Rolling process was conducted in reversible way with deformation degree of 60% (30%-30%) and before each pass of the rolling the material is heated up to temperature 300oC with different holding time from 30, 60, and 120 minutes. The results showed that as the longer holding time of the heating and was continued by further deformation, it affects the grain size to be much smaller from 92.2 μm to 36.5 μm. In addition, it is also found an increasing of annealed twin, deformed twin, as well as finer and newer grains that indicate partial dynamic recrystallization.
THE EFFECT OF FLY ASH UTILIZATION IN REINFORCEMENT CONCRETE: A REVIEW Rachmat Hermawan; Rini Riastuti
Indonesian Journal of Engineering and Science (IJES) Vol. 3 No. 1 (2022): Table of Contents
Publisher : Asosiasi Peneliti Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (170.834 KB) | DOI: 10.51630/ijes.v3i1.37

Abstract

Indonesia signed the Paris Agreement on facing climate change. Carbon dioxide is the main issue contributing to the greenhouse effect. Most power plant in Indonesia uses non-renewable energy to generate electricity. Increasing demand for electricity makes increasing coal consumption for steam power plants and directly contributes to greenhouse gasses from coal combustion and produces fly ash as a waste product. Otherwise, fly ash from Steam Power Plant is classified as pozzolanic materials being a part of substitution ordinary portland cement (OPC) on making reinforcement concrete. Many Researchers studied reinforcement concrete from fly ash composition and others development using renewable energy resources such as biomass. This paper presents a literature review on focus studying the properties of various types of fly ash and their effect on the performance of concrete, including corrosion resistance.
A STUDY OF STRESS CORROSION CRACKING RESISTANCE FOR COLD FORMING PLASTIC DEFORMED Cu-30Zn ALLOY Gadang Priyotomo; Akhmad Faizal; Rini Riastuti
Widyariset Vol 4, No 1 (2018): Widyariset
Publisher : Pusbindiklat - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1019.12 KB) | DOI: 10.14203/widyariset.4.1.2018.29-36

Abstract

Cu-30Zn alloy has good atmospheric corrosion resistance. It is mainly used as automotive radiator cores, ammunition component, lamp fixture, flashlight shells and kickplates. Cold rolled Cu-30Zn with deformation degree 33,87% at 300OC was tested its Stress Corrosion Cracking (SCC) property. Stress corrosion cracking (SCC) of a Cu–30Zn has been investigated using Mattsson solutions 0,5 M (NH4)2SO4 + 0,05 M CuSO4 in room temperature by using a constant load method. Cu-30Zn has a weakness on stress corrosion cracking in ammonia environment (mattson solution). Scanning electron microscope (SEM) testing indicated the failure of cold roll Cu-30Zn was a transgranular cracking. Furthermore, cracking occued at stress below yield stress. Energy dispersive Spectroscopy (EDS) test exhibited dezincification indication on fracture surface. The visual examination of surface morphology on alloy showed discoloration from yellow to red. Homogenized Cu-30Zn showed better SCC resistance than cold rolled Cu-30Zn.
CORROSION BEHAVIOR OF SUPER AUSTENITIC STAINLESS STEEL, DUPLEX 2205 AND 316L IN SULFAMIC ACID ENVIRONMENT Bashari R Roszardi; Rini Riastuti; Wahyu Budiarto; Nono Darsono; Adi Noer Syahid
NUSANTARA : Jurnal Ilmu Pengetahuan Sosial Vol 9, No 2 (2022): NUSANTARA : Jurnal Ilmu Pengetahuan Sosial
Publisher : Universitas Muhammadiyah Tapanuli Selatan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31604/jips.v9i1.2022.85-91

Abstract

Currently, sulfuric acid as a primary chemical industrial material is ubiquitous. One of its uses is a sweetener. Due to its corrosive nature, it is necessary to use a suitable container to avoid contamination of the solution. Corrosion behavior of super austenitic stainless steel, duplex 2205, and 316L uncovered to sulfamic acid in diverse attention at ambient temperature had been investigated. Concentration Weight loss method, Potentiodynamic Polarization, and Electrochemical Impedance Spectroscopy (EIS) examined the corrosion rate. The result showed that the corrosion rate of material increased with the increasing concentration of sulfamic acid. Super austenitic stainless steel has higher corrosion resistance than duplex 2205 and 316L.  
TEXTURE CHARACTERIZATION OF THE COPPER PRODUCED BY ECAP PROCESS USING NEUTRON DIFFRACTION TECHNIQUE Muhammad Refai Muslih; Tri Hardi Priyanto; Muhammad Rifai; Andryansah Andryansah; Rini Riastuti
Jurnal Sains Materi Indonesia Vol 23, No 2: APRIL 2022
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2022.23.5.6604

Abstract

TEXTURE CHARACTERIZATION OF THE COPPER PRODUCED BY ECAP PROCESS USING NEUTRON DIFFRACTION TECHNIQUE. Texture and hardness characterization have been carried out on market copper samples that have gone through the equal channel angular pressing (ECAP) process. Neutron diffraction technique had been used for obtaining an average crystalline texture in a particular volume non destructively to the sample. The ECAP process is carried out once (1 pass) with some parts that have been plastically deformed and some parts that have not been deformed. Crystalline texture and hardness were observed in the deformed and non-deformed parts. Initial characterization was carried out by X-ray diffraction (XRD) followed by measurement of crystal texture using the neutron diffraction technique, while hardness was tested using the Vickers method. Rod-shaped sample with a diameter of 10 mm. Texture observations were performed at the center of the sample with a neutron beam limiting slit of 5x5 mm2 . There was an increase in hardness in the deformed position compared to the undeformed one. The texture that occurs is in the form of fibers with different directions and indexes, sequentially as follows: position 1, [111] of 4.96 m.r.d., position 2, -[111] of 1.86 m.r.d. and position 3 [010] of 2.44 m.r.d. , position 4 orientation is distributed on [011], [013], [115], [235] fibers with a texture index range of 1.07–1.33 m.r.d.
PENGARUH PENINGKATAN % REDUKSI TERHADAP PENGHALUSAN BUTIR DAN SIFAT MEKANIK PADUAN Cu-Zn 70/30 SETELAH DEFORMASI PADA SUHU 400°C Eka Febriyanti; Amin Suhadi; Rini Riastuti; Dedi Priadi
Majalah Ilmiah Pengkajian Industri Vol. 10 No. 3 (2016): Majalah Ilmiah Pengkajian Industri
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/mipi.v10i3.155

Abstract

 Paduan Cu-Zn 70/30 banyak digunakan dalam berbagai aplikasi industri karena memiliki sifat yang unggul dan belum ada penggantinya. Untuk memperoleh paduan Cu-Zn 70/30 dengan sifat mekanik yang tinggi maka dilakukan riset baik modifikasi dari jenis material yang sudah ada ataupun material baru agar sesuai dengan kebutuhan industri. Untuk mengurangi biaya produksi, namun tetap menghasilkan sifat mekanik yang baik tanpa penambahan paduan maka dikembangkan metode penghalusan butir. Salah satu alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 yaitu dengan metode warm rolling. Warm rolling yang dilakukan pada pelat paduan Cu-Zn 70/30 menggunakan % reduksi sebanyak 29,03%, 34,4%, dan 38,16% pada suhu 400°C secara double pass reversible. Untuk paduan Cu-Zn 70/30, rentang pengerjaan warm rolling berada pada suhu 0,4 s/d 0,6 Tm (melting point) yaitu berkisar antara 382°C-573°C. Hasil metalografi didapat ukuran butir yang semakin menurun sebesar 30,03 µm di bagian tepi dan 33,45 µm di bagian tengah pada % reduksi 38,16%. Hasil uji tarik dengan % reduksi 38,16% menghasilkan nilai ultimate tensile strength (UTS) sebesar 478 MPa, yield strength (YS) sebesar 434 MPa, dan persentase elongasi sebesar 9%. Untuk hasil uji kekerasan menghasilkan nilai kekerasan sebesar 135,8 HV di bagian tepi dan 128,4 HV di bagian tengah pada % reduksi 38,16%. 
ANALISIS MAMPU BENTUK BAHAN BAKU SELONGSONG MUNISI Cu-Zn 70/30 SETELAH DEFORMASI PADA SUHU 500ºC = ANALYSIS FORMABILITY OF RAW MATERIALS CU - ZN MUNITIONS CASINGS 70/30 AFTER DEFORMATION AT TEMPERATURE 500ºC Eka Febriyanti; Amin Suhadi; Dedi Priadi; Rini Riastuti
Majalah Ilmiah Pengkajian Industri Vol. 9 No. 3 (2015): Majalah Ilmiah Pengkajian Industri
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/mipi.v9i3.1648

Abstract

casing because both processes have important role to derive raw material into the required form, dimensions and characteristics. Cu-Zn 70/30 alloy is raw material which normally used as munition casing however, its formability after deformation and heat treatment is not widely known. Therefore, this research has an objective to study the effect of deformation at warm temperature on cold formability by introducing thermomechanical controlled processed in warm rolling. Warm rolling have been conducted by double pass reversible method on 25% x 2, 30% x 2, and 35% x 2 at temperature 500oC. Evaluation of formability have been done by limited tensile test up to 20% elongation and full tensile test until rupture. The result of this research indicates that the best formability of Cu-Zn 70/30 is obtained on specimen which are deformed by warm rolling at actual degree of deformation 38.7%. Formability testing result for his specimen under designated warm rolling parameter has an elongation 10 % with strain hardening coefficient 0.00228, average normal anisotropy value 0.5452, and plannar anisotropy value Δr<1 is: -0.42. ABSTRAKDeformasi dan perlakuan panas selalu menyertai proses pembuatan selongsong peluru karena kedua proses tersebutlah yang mampu mengatur bahan baku menjadi bentuk dan dimensi yang diinginkan serta sesuai dengan karakteristik yang dikehendaki. Padaun Cu-Zn 70/30 adalah bahan baku yang digunakan untuk pembuatan selongsong peluru, namun mampu bentuk paduan ini akibat deformasi dan perlakuan panas belum banyak diketahui. Oleh karena itu pada penelitian ini bertujuan untuk mempelajari pengaruh deformasi yang dilakukan pada suhu hangat terhadap mampu bentuk dingin dengan metode thermomechanical controlled processed menggunakan teknologi canai hangat. Teknologi canai hangat dilakukan dengan metode double pass reversible sebanyak 25% x 2, 30% x 2, dan 35% x 2 pada suhu 500oC. Pengamatan mampu bentuk dilakukan dengan pengujian tarik hanya sampai perpanjangan 20% serta uji tarik sampai putus. Hasil dari penelitian menunjukkan bahwa sifat mampu bentuk terbaik diperoleh pada benda uji yang dideformasi canai hangat di temperatur 500oC dengan derajat deformasi aktual sebesar 38.7%. Apabila dilihat dari sifat mampu bentuknya maka benda uji yang dideformasi canai hangat pada kondisi parameter penelitian ini memiliki nilai elongasi sebesar 10 % dengan nilai koefisien pengerasan regang yang tinggi sebesar 0.00228, nilai anisotropi normal rata-rata sebesar 0.5452, dan nilai anisotropi planar yaitu Δr<1 sebesar -0.42.
Effect of Thiosulfate Concentration and Leaching Temperature in Ammoniacal Thiosulfate Leaching of Refractory Sulfide Gold Ore Rini Riastuti; Kautsar Muwahhid; Ahmad Maksum; Johny Wahyuadi Soedarsono; Mhd. Ibkar Yusran Asfar
Jurnal Mettek: Jurnal Ilmiah Nasional dalam Bidang Ilmu Teknik Mesin Vol 8 No 2 (2022)
Publisher : Program Studi Magister Teknik Mesin Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/METTEK.2022.v08.i02.p09

Abstract

Tiosulfat sebagai larutan pelindian emas pertama kali dipelajari pada tahun 1979 untuk menemukan alternatif larutan sianida dan merkuri yang banyak digunakan dalam industri ekstraksi emas meskipun berdampak negatif bagi lingkungan. Sampel bijih yang digunakan adalah bijih asli dari Bolaang Mongondow, Sulawesi Utara. Berdasarkan pengamatan Mikroskop Optik dan karakterisasi LIBS, terdapat senyawa pirit yang merupakan salah satu karakteristik bijih sulfida. Menurut fluoresensi sinar-X dan Inductively Coupled Plasma, bijih mengandung sekitar 14,62% ??Fe, 6,69% ??S, 0,15% Cu, dan 0,27 ppm Au. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi tiosulfat dan temperatur pelindian pada pelindian tiosulfat amoniak bijih emas sulfida refraktori terhadap kelarutan emas. Penelitian ini dilakukan dengan metode leaching skala laboratorium. Hasil leaching kemudian diperiksa dengan Inductively Coupled Plasma (ICP). Konsentrasi tiosulfat (0,05M, 0,1M, dan 0,2M) dan pengaruh temperatur (25?C, 40?C, 60?C) dipelajari. Ekstraksi emas maksimum (62%) diperoleh dengan menggunakan konsentrasi tiosulfat 0,1M pada 40?C selama 2 jam dengan kepadatan pulp 20%. Kecepatan pengadukan dan pH larutan berair masing-masing adalah 400 rpm dan 10. Berdasarkan hasil tersebut dapat disimpulkan bahwa konsentrasi larutan tiosulfat dan temperatur pelindian akan mempengaruhi kelarutan emas. Thiosulfate as gold leach solution first studied in 1979 to found alternative of cyanide and mercury solution which are widely used in gold extraction industry although it’s negative impact for the environment. The ore sample is native ore from Bolaang Mongondow, North Sulawesi. According to Optical Microscope observation and LIBS characterization, there are pyrite compound which is one of the chacaracteristic of sulfide ore. According to X-ray fluorescence and Inductively Coupled Plasma, the ore contained about 14.62% Fe, 6.69% S, 0.15% Cu, and 0.27 ppm Au. This study aimed to determine the effect of thiosulfate concentration and leaching temperature in ammoniacal thiosulfate leaching of refractory gold sulfide ores on the solubility of gold. This research was conducted by laboratory scale of leaching method. The leaching result is then checked by Inductively Coupled Plasma (ICP). The concentration of thiosulfate (0.05M, 0.1M, and 0.2M) and the effect of temperature (250 C, 400 C, 600 C) were studied. Maximum gold extraction (62%) was obtained using 0.1M of thiosulfate concentrations at 400 C for 2 h with 20% of pulp density. Stirring speed and the pH of the aqueous solution were 400 rpm and 10, respectively. According to the results, it can be concluded that the concentration of Thiosulfate solution and leaching temperature will affect the dissolution of gold.
Co-Authors Abdullah, Abdul Halim Adam Hidana Yudo Saputro, Adam Hidana Yudo Adi Noer Syahid Adipurnama, Iman Agus Supriyanto Ahmad Fadli Ahmad Fadli Ahmad Maksum Ahmad Zakiyuddin Akhmad Faizal Alfian Alfian Amalia, Dinda Putri Amanda, Putri Amin Suhadi Amin Suhadi Amin Suhadi Amin Suhadi Amin Suhadi Amin Suhadi, Amin Andryansah Andryansah Anjar Oktikawati Aqila, Daffa Aulia, Hafiz Ayu Rizeki Ridhowati Ayu Rizeki Ridhowati Azizah Intan Pangesty Badrul Munir, Badrul Bashari R Roszardi Baskoro, Agung budiarto, wahyu Chalid, Muchamad Dedi Priadi Dedi Priadi Dedi Priadi Dedi Supriadi Diana Natalia Eka Febriyanti Eka Febriyanti Eka Febriyanti Eka Febriyanti Eka Febriyanti Eka Febriyanti Eka Febriyanti Eka Febriyanti Febi Dwi Antony Febriyanti, Eka febriyanti, eka febriyanti, eka Gadang Priyotomo Gadang Priyotomo Hari Eko Irianto Ibrahim, Muhammad Hamka Ifah Munifah Irawan, Januar IRWAN WIJAYA J.W. Soedarsono Jamal Basmal, Jamal Jamhari Jamhari Johny Wahyuadi Soedarsono Kaban, Agus S Kautsar Muwahhid Kautsar Muwahhid Kusumaningrum, Wida Banar Manurung, Rizky Rama Putra Marda, Yanuar Mohamad Mega Herawati Arifiana Amanah Notonegoro, Mega Herawati Arifiana Amanah Mhd. Ibkar Yusran Asfar Mochamad Chalid Muhammad Refai Muslih Muhammad Rifai Muhammad Yunus Muhammad Yunus Najmudin, Muhammad Guruh Nikitasari, Arini Nono Darsono Nono Darsono, Nono Nurhayati Nurhayati Nurhayati Paltgor, Rinush Fedrikdo Putri Salsabila, Syanatha Rachmat Hermawan Rahardian, Krisnandha Ramadhani, Rizal T Ramadhani, Rizal Tresna Ramdhani, Rizal Tresna Riady, Rado Ridhowati, Ayu Rizeki Ridhowati, Ayu Rizeki Rinta Kusumawati, Rinta Rinush Fedrikdo Paltgor Rizal Tresna Ramdhani Roszardi, Bashari R Roszardi, Bashari Rohululloh Roziafanto, Ahmad Nandang Santoso, Irwan Wijaya SATRIYAS ILYAS Sunarso Sunarso Syahid, Adi Noer Tiggor, Triadhi Panthun Tri Handayani Tri Hardi Priyanto Wahyu Budiarto Widianto, Shilla Rizqi Winarto Winarto Yuanto, Nursidi