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Abstrak :
[ABSTRAK
Penggunaan baja tahan karat dua fasa austenitik-ferritik (Duplex) UNS32205 telah digunakan secara luas pada berbagai sektor perusahaan, khususnya industri Minyak dan Gas serta industri Petrokimia karena memiliki sifat mekanik dan ketahanan korosi yang sangat baik. Pada penelitian ini,yang diamati adalah pengaruh konsentrasi NaCl pada lingkungan kerja baja tahan karat ini, yang bertujuan mencari konsentrasi yang bersifat paling korosif, dan juga dilakukan pengamatan terhadap pengaruh perubahan Ferrite Content atau nilai rasio dari kedua fasa penyusun baja tahan karat UNS32205 yaitu Austenit dan Ferrit.Pada sampel awal yang diamati tanpa diberikan perlakuan panas apapun memiliki nilai rasio fasa 40% Austenit ? 60 Ferrit. Perubahan Ferrite Content atau perubahan rasio tersebut dilakukan dengan melakukan dua metode pemanasan sampel. Yaitu pemanasan menggunakan maffle furnace pada temperatur 11000C dan ditahan selama 20 menit, dengan hasil rasio 42% Austenit ? 58% Ferrit dan nilai ketahanan korosi paling rendah. Dan juga dilakukan pemanasan dengan cara mengambil sampel pada daerah HAZ dengan temperatur antara 4000C-12000C dan langsung quench, dengan hasil pengamatannya adalah memiliki ketahanan korosi paling tinggi karena memiliki rasio 50,3% Austenit ? 49,7% Ferrit. ABSTRACT
The use of Duplex Stainless Steel UNS32205 has been widely used in various sectors of the company, particularly the oil and Gas industry and the petrochemical industry because it has excellent mechanical properties and corrosion resistance. In this study, the effect of NaCl concentration was observed on the stainless steel working environment, which aims to find the most corrosive nature of concentrations, and also carried out observations on the influence of Ferrite Content or change the value of the ratio of the phase constituent of stainless steel UNS32205 i.e. Austenite and Ferrite. On the initial samples were observed without any heat treatment has given the value of the phase ratio 40% Austenite ? 60 Ferrite. Ferrite Content changes or changes the ratio by doing two sample heating method. I.e. the heating furnace temperature on maffle using 11000C and detained for 20 minutes, with a ratio of 42% Austenit ? 58% Ferrit and lowest corrosion resistance value. And also done warming up by taking samples at the HAZ with temperature between 4000C-12000C and direct quench, with the results of its observations is to have the highest corrosion resistance because it has a ratio of 50.3% Austenite ? 49.7% Ferrite. , The use of Duplex Stainless Steel UNS32205 has been widely used in various sectors of the company, particularly the oil and Gas industry and the petrochemical industry because it has excellent mechanical properties and corrosion resistance. In this study, the effect of NaCl concentration was observed on the stainless steel working environment, which aims to find the most corrosive nature of concentrations, and also carried out observations on the influence of Ferrite Content or change the value of the ratio of the phase constituent of stainless steel UNS32205 i.e. Austenite and Ferrite. On the initial samples were observed without any heat treatment has given the value of the phase ratio 40% Austenite – 60 Ferrite. Ferrite Content changes or changes the ratio by doing two sample heating method. I.e. the heating furnace temperature on maffle using 11000C and detained for 20 minutes, with a ratio of 42% Austenit – 58% Ferrit and lowest corrosion resistance value. And also done warming up by taking samples at the HAZ with temperature between 4000C-12000C and direct quench, with the results of its observations is to have the highest corrosion resistance because it has a ratio of 50.3% Austenite – 49.7% Ferrite. ]

Abstrak :
Dilakukan studi tentang ketahanan korosi baja tahan karat austenitik seri 304L pada berbagai konsentrasi larutan NaCl. Percobaan dilakukan dengan metode electrochemical impedance spectroscopy EIS pada temperatur ruang yang bertujuan untuk mengevaluasi mekanisme korosi sampel berdasarkan tahanan polarisasi dan impedansi kapasitansinya.Percobaan dilakukan dalam berbagai konsentrasi larutan NaCl, yaitu 1 , 2 , 3.5 , 4 and 5 w.t. Hasil percobaan, yang direpresentasikan dengan grafik Nyquist dan rangkaian listrik ekuivalen, menunjukkan bahwa besarnya impedansi sampel, yang mana menunjukkan ketahanan korosinya, dipengaruhi oleh konsentrasi larutan NaCl. Besarnya nilai impedansi baja tahan karat 304L dari yang paling tinggi ke yang paling rendah berada pada larutan NaCl dengan konsentrasi: 1 , 2 , 5 , 4 , 3.5 w.t NaCl. Telah diamati bahwa ketahanan korosi terendah dari sampel berada pada larutan NaCl konsentrasi 3.5 w.t NaCl, yang mana serupa dengan air laut pada umumnya. Hal ini terjadi karena kelarutan optimimum dari oksigen terlarut terjadi pada larutan NaCl konsentrasi 3.5 w.t.NaCl. Kata kunci : Baja tahan karat 304L, Perilaku Korosi, Ketahanan Korosi, pengaruh konsentrasi NaCl, electrochemical impedance spectroscopy. ......Corrosion behavior of austenitic stainless steel 304L type in various concentrations of aqueous sodium chloride solutions was investigated. Experimental testing method was carried out by using electrochemical impedance spectroscopy EIS at room temperature 27oC to evaluate the change of corrosion mechanism based on its polarization resistance and capacitive impedance.Aqueous sodium chloride solutions were prepared with various concentration i.e. 1 , 2 , 3.5 , 4 and 5 w.t. The testing results which were represented by Nyquist graphs and electrochemical equivalent circuits showed that the impedance magnitudes of austenitic stainless steel which indicated its corrosion resistance were influenced by sodium chloride concentrations. Rank of impedance magnitude of SS 304L at various chloride concentrations from the highest to the lowest were 1 , 2 , 5 , 4 , 3,5 w.t NaCl consecutively. It was observed that the lowest corrosion resistance of alloys was at 3,5 w.t NaCl which was similar to typical seawater solution. This was caused by the presence of maximum dissolved oxygen solubility.

Abstrak :
Teh rosella merupakan bahan organik yang dapat dikembangkan sebagai inhibitor untuk mengurangi laju korosi baja karbon rendah di lingkungan air laut pada temperatur 50°C. Penggunaan teh rosella diharapkan dapat dijadikan sebagai inhibitor yang bersifat aman, ramah lingkungan, serta bio-degradable dan juga dapat mengurangi penggunaan bahan sintetis. Inhibitor teh rosella dipilih sebagai inhibitor organik karena mengandung zat antioksidan yang dapat menghambat proses korosi, seperti antosianin dan asam askorbat. Metode kehilangan berat digunakan untuk menguji keefektifan teh rosella sebagai inhibitor dengan variasi konsentrasi (tanpa inhibitor, 2ml, 4ml, 6ml) dan lama perendaman selama 5 hari. Hasil penelitian menunjukkan bahwa penambahan inhibitor teh rosella yang paling efektif bila digunakan pada lingkungan NaCl 3.5% pada temperatur 50°C adalah pada penambahan 2 ml dengan efisiensi 17.768 %. ......Roselle tea is organic materials that can be developed as inhibitors to reduce corrosion rate of low carbon steel on sea water solution in 50°C. Roselle tea is uspected to be one of inhibitors which is safe, friendly environment, dan bio-degradable and alsocan reduce the use of organic materials. Roselle tea inhibitors have been chosen as organic inhibitors because its containing antioxidants that can reduce corrosion process, example anhthosianin and ascorbic acid. Weight loss method is used to teat the effectiveness of roselle tea as an inhibitors with various concentration ( without inhibitors, 2ml, 4ml, and 6ml) and period of immersion teat is 5 days. The result of research showed that addition roselle tea inhibitors most effective if used on NaCl 3.5% solution in temperature 50°C is with additon 2ml with an efficciency 17.768 %.

Abstrak :
Teh rosella merupakan bahan organik yang dapat dikembangkan sebagai inhibitor untuk mengurangi laju korosi baja karbon rendah di lingkungan air laut pada temperatur 40°C. Penggunaan teh rosella diharapkan dapat dijadikan sebagai inhibitor yang bersifat aman, ramah lingkungan, serta bio-degradable dan juga dapat mengurangi penggunaan bahan sintetis. Inhibitor teh rosella dipilih sebagai inhibitor organik karena mengandung zat antioksidan yang dapat menghambat proses korosi, seperti antosianin dan asam askorbat. Metode kehilangan berat digunakan untuk menguji keefektifan teh rosella sebagai inhibitor dengan variasi konsentrasi ( tanpa inhibitor, 2ml, 4ml, 6ml) dan lama perendaman selama 5 hari. Hasil penelitian menunjukkan bahwa penambahan inhibitor teh rosella yang paling efektif bila digunakan pada lingkungan NaCl 3,5% pada temperatur 40°C adalah pada penambahan 2 ml dengan efisiensi 13,2%. ......Roselle tea is organic materials that can be developed as inhibitors to reduce corrosion rate of low carbon steel on NaCl 3,5% solution in 40°C. Roselle tea is uspected to be one of inhibitors which is safe, friendly environment, dan biodegradable and alsocan reduce the use of organic materials. Roselle tea inhibitors have been chosen as organic inhibitors because its containing antioxidants that can reduce corrosion process, example anhthosianin and ascorbic acid. Weight loss method is used to test the effectiveness of roselle tea as an inhibitors with various concentration ( without inhibitors, 2ml, 4ml, and 6ml) and period of immersion test is 5 days. The result of research showed that addition roselle tea inhibitors most effective if used on NaCl 3,5% solution in temperature 40°C is with additon 2ml with an efficciency 13,2%.