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"Paduan aluminium banyak digunakan dalam berbagai aplikasi, terutama di bidang otomotif dan penerbangan karena keunggulannya. Aluminium bersifat ringan, kekuatan tinggi, serta densitas rendah. Namun, sifat mekanik dan ketahanan korosinya perlu ditingkatkan. Plasma Electrolytic Oxidation (PEO) adalah metode terbaru untuk melindungi aluminium dengan menumbuhkan lapisan keramik oksida pada permukaannya. Dalam penelitian ini, proses PEO dilakukan pada paduan aluminium seri 1100 dan 7075-T735 dengan elektrolit campuran 30 g/Na2SiO3, 30 g/l KOH, dan 20 g/l TEA dengan rapat arus 200 A/m2 selama 6 menit. Kedua jenis seri paduan tersebut digunakan sebagai pembanding dalam proses PEO dimana seri 1100 tergolong Al murni sedangkan seri 7075 memiliki banyak presipitat. Hasil uji korosi dengan menggunakan uji elektrokimia menunjukkan bahwa sampel AA7075-T735 berlapis PEO memiliki ketahanan korosi yang paling baik. Hal ini dibuktikan dengan nilai rapat arus korosi (icorr) terendah, yaitu mencapai 5,91x10-7 A.cm-2 dan loop kapasitif yang paling besar serta ketidakhadiran loop induktif pada kurva Nyquist. Dari uji hilang berat juga diperoleh hasil rata-rata hilang berat yang lebih rendah pada sampel AA7075-T735 dibandingkan dengan AA1100. Ketahanan korosi sampel berlapis PEO mengikuti perilaku substratnya. Sampel AA1100 mengalami degradasi coating yang lebih dominan daripada AA7075-T735. Hal ini berkaitan dengan porositas dan kepadatan lapisan PEO pada kedua sampel.

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Aluminum alloys are widely used in various applications, especially in the automotive and aviation industries, due to their advantages. Aluminum is lightweight, has high strength, and low density. However, its mechanical properties and corrosion resistance need improvement. Plasma Electrolytic Oxidation (PEO) is the latest method used to protect aluminum by growing a ceramic oxide layer on its surface. In this study, the PEO process was applied to aluminum alloys of series 1100 and 7075-T735 using an electrolyte mixture of 30 g/L Na2SiO3, 30 g/L KOH, and 20 g/L TEA with a current density of 200 A/m2 for 6 minutes. Both alloy series were used as comparators in the PEO process, with series 1100 being classified as pure Al, while series 7075 has numerous precipitates. Corrosion tests using electrochemical analysis showed that the PEO-coated AA7075-T735 sample exhibited the best corrosion resistance. This was evident from its lowest corrosion current density (icorr) value, which reached 5.91x10-7 A.cm-2 , as well as the largest capacitive loop and the absence of an inductive loop in the Nyquist curve. Weight loss tests also indicated that the average weight loss was lower in the AA7075-T735 sample compared to AA1100. The corrosion resistance of the PEO-coated samples followed the behavior of their substrates. The AA1100 sample experienced more dominant coating degradation compared to AA7075-T735, which was related to the porosity and density of the PEO layer in both samples."

"ABSTRAKIn order to maintain issued of environmental safe and clean, Indonesian government has been tried very hard to reduce toxicity, especially in water cooling systems by prohibiting chromate to be used.A part from inhibitor chromate, the industries still use some inhibitors such as zinc phosphate, polyphosphonat etc, but the dangers of these inhibitors still unsolved. To anticipated of this condition, in this time has been made an advances of development of unpoisonous inhibitor called Ascorbic Acid (vitamin C).The investigation started with behaviour of Ascorbic Acid in near neutral aqueous solution regarding corrosion of stainless steel. The experiment result indicated that inhibition of Ascorbic Acid gave effectiveness of 75 - 83 %. with intervals of 60 - 100 ppm. This effectiveness values can be said that Ascorbic Acid very promising to be used for inhibitor corrosion. Furthermore research must take place to get more information about inhibition of Ascorbic Acid, so that Ascorbic Acid can be used commercially in industries."

"Analisa Fitness For Service FFS sangat bermanfaat bagi proses maintenance dan inspeksi untuk menindaklanjuti hasil inspeksi, terutama untuk mengambil keputusan terkait run, repair atau re-rate. Seiring berjalannya waktu dan interaksi dengan lingkungan, peralatan-peralatan produksi akan mengalami degradasi sehingga untuk melihat pengaruh-pengaruh dari degradasi tersebut terhadap kehandalan perlu dilakukan analisis FFS. Hal ini dapat juga digunakan untuk mereaktifasi dan atau meningkatkan kehandalan sarana penimbunan minyak dan gas, sehingga perlu adanya parameter yang mampu terukur / terkuantifikasi karena tingginya resiko kecelakaan dalam operasi di sektor minyak dan gas. Dalam tugas akhir ini peralatan dianalisis dengan menggunakan standar API 579 bagian 4, 5, 9 dan 14 untuk tingkat 1 dan 2. Metode ini terdiri dari beberapa langkah perhitungan matematika yang rumit, maka untuk mempermudah menganalisa dikembangkan program bantu perhitungan untuk masing-masing tingkatan tersebut dengan menggunakan Visual Basic 2012. Studi kasus dilakukan pada sarana mechanical static, yang meliputi tangki timbun vertical DSTs dan ST, cone mixer, dan KO Drum. Studi kasus dilakukan pada beberapa sarana penyimpanan minyak dan gas yang sudah berumur lebih dari 10 tahun. Dari hasil inspeksi dapat disimpulkan bahwa umumnya pada tangki timbun terjadi general corrosion thickness covarians < 10, namun ada juga peralatan yang mengalami localize thin area LTA . Untuk peralatan yang mengalami LTA perlu dilakukan root cause analysis agar LTA tidak berlanjut dan dapat dihentikan. Peralatan yang mengalami crack like flaw CLF dan fatigue perlu dilakukan analisa FFS dan apabila masih layak maka dapat langsung beroperasi dengan normal tanpa adanya perbaikan. Pada akhir penelitian penulis juga melakukan analisa studi parameter yang dapat mempengaruhi integritas komponen yang mengalami general corrosion, LTA dan CLF. Dimana dengan semakin bertambahnya nilai dari parameter tersebut maka integritas komponen akan menurun sehingga menjadi tidak aman dioperasikan.

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Fitness For Service FFS analysis is very usefull for maintenance and inspection in order to make post inspection analysis, especially to take decision about run, repair or re rate. As time went on and interaction with the environment, those equipments will be degraded thus it will affect the reliability of equipments, and company needs to analyze the effect of degradation for equipments lifetime by using FFS methods. In order to reactivate or increase component lifetime in oil and gas facility, many parameters and quantification method is needed because of the high risk of oil and gas operating condition. In this final task, the equipment has been analyzed using standard API 579 section 4, 5, 9 and 14 for levels 1 and 2. The method consists of several steps complex mathematical calculations, so to make it easier to do analysis writer has developed software for the calculation of each of these levels using Visual Basic 2012. Many case studies also carried out in static mechanical equipment, which include vertical storage tank DSTs and ST, cone mixer and KO Drum. The case study is taken from oil and gas storage facility which has been used for more than 10 years.

From the results of the inspection can be concluded that mostly in storage tanks will occurs general corrosion thickness covarians 10, but there are many possibilities that localize thin area LTA also happen. For equipments that damaged by LTA, root cause analysis should be done in order to stop the LTA and solve the corrosion problem. Equipments that has crack like flaw CLF and fatigue, FFS analysis should be done and if those equipments pass the FFS assessment then normal operation still can continue without any major repair. In the last research writer has analyze parameters that can affect the integrity of the components that has general corrosion, LTA and CLF. Where with the increasing values of the parameters then the integrity of the components will be decreased so that it becomes unsafe to operate. "

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Kegagalan sistem perpipaan pada industri minyak bumi dan gas merupakan kondisi yang sangat dihindari dan diantisipasi karena kerugian yang dihasilkan dapat mencapai sangat tinggi. Salah satu penyebab yang mengakibatkan kegagalan sistem perpipaan adalah korosi internal. Korosi internal ini disebabkan oleh kandungan karbon dioksida dan zat-zat yang korosif di dalam minyak bumi dan gas. Untuk mengantisipasi kegagalan yang dapat terjadi, dibutuhkan sistem inspeksi yang optimal sehingga tidak hanya dapat mencegah terjadinya korosi yang mengakibatkan kegagalan sistem perpipaan namun juga overbudgetting akibat inspeksi yang terlalu sering. Risk Based Inspection (RBI) merupakan salah satu metode untuk menentukan sistem inspeksi secara optimal dengan menggunakan pendekatan risiko. Dalam pendekatan penghitungan risiko, simulasi monte carlo dapat digunakan untuk mendekati nilai risiko aktual pada kondisi lapangan dengan jumlah sampel yang sedikit. Dalam simulasi monte carlo ini digunakan dua jenis fungsi laju korosi yang sesuai dengan ASTM G-16 95. Dengan membandingkan jenis fungsi laju korosi linier yang umumnya digunakan dalam penghitungan laju korosi di lapangan dengan fungsi laju korosi non-linier akan menghasilkan pendekatan nilai risiko yang lebih akurat. Dengan pendekatan nilai risiko yang lebih akurat, sistem inspeksi yang dihasilkan dalam akan lebih optimal.

 

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Failures in oil and gas piping system are a condition which may occur and resulting in high amount of loses. One of the main causes on pipeline system failure is Internal corrosion. This internal corrosion is occurred due to high content of carbon dioxide gasses and other corrosive substances inside crude oil and natural gasses. Therefore, an optimum inspection scheduling system will be needed not only to intercept the probability of pipeline failures caused by corrosion but also to prevent overbudgeting on excessive inspection scheduling. For this purpose, Risk-Based Inspection (RBI) is used based on API RP 581 document as a standard procedure of analysis. Also, in this paper Monte Carlo simulation will be applied using stochastic iteration to approximate the actual risk value of the pipeline system with limited amount of sample on site. In addition, the non-linear corrosion rate function is used as a comparison to the commonly used linear corrosion rate function based on the ASTM G-16 95 document. The results show non-linear corrosion rate function will generate more accurate approach on approximating the actual risk value and eventually resulting in more efficient inspection scheduling system during the lifetime of the pipe system.

 

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"This volume contains the proceedings of the 8th International PhD Student Workshop on Service Life and Durability of Reinforced Concrete Structures that was held in Marne-la-Vallee, France, on September the 26th and 27th 2016.Topics discussed in the book are related to durability performance of reinforced concrete, service life modelling, prevention, protection and repair.Reinforced concrete structures may prove to be very durable, however, their gradual degradation over time impairing both serviceability and structural safety is still a matter of great practical concern in view of the large economic consequences for assessment, maintenance and repair. Corrosion of steel reinforcement is considered to be the most detrimental process responsible for structural deterioration.Many studies are in progress to develop a comprehensive engineering approach for assessment of the initiation and the propagation period of corrosion in both uncracked and cracked concrete. Modelling of chloride penetration and carbonation has attracted a great deal of attention in recent years, however, there is still much debate on several essential aspects such as the chloride threshold level. ASR, and acid, sulphate and frost attack and other mechanisms remain important areas of study. In addition, the interaction between different degradation mechanisms requires further understanding.The worskhop was organised under the auspices of RILEM EAC (Educational Activities Committee), with the aim to bring together young researchers in the field of durability of concrete."

"Baja rendah karbon adalah paduan logam yang umum digunakan pada industri minyak dan gas. Sifatnya yang rentan terhadap korosi mendukung pengembangan inhibitor korosi organik yang dapat terbiodegradasi dan lebih mudah untuk disintesis. Penelitian ini berupaya untuk mensintesis inhibitor korosi TETA-MSRBD (trietilentetramin-minyak sawit RBD) melalui metode refluks yang kemudian discale-up menggunakan reaktor tangki BSTR (Batch Stirred Tank Reactor) pada variasi temperatur 140°C, 150°C, 160°C dan 170°C dengan variasi kecepatan pengadukan pada 700, 1000, dan 1200 rpm. Sintesis pertama berlangsung pada temperatur 150°C dengan kecepatan pengadukan 1200 rpm, mengikuti kondisi reaksi optimum sintesis imidazolin dari minyak sawit berdasarkan studi sebelumnya, menghasilkan TETA-MSRBD A dengan persentase konversi sebesar 66,85% setelah penentuan angka saponifikasi. Variasi kondisi reaksi dilanjutkan hingga didapatkan persentase konversi tertinggi sebesar 83,43% pada temperatur 150°C dengan kecepatan pengadukan 1000 rpm. Kedua produk dimurnikan (TETA-MSRBD B1 dan B2) dan dilanjuti dengan karakterisasi menggunakan instrumentasi spektrofotometri UV-Visibel, spektroskopi FTIR, serta LC-MS. Hasil karakterisasi menunjukkan bahwa kedua produk TETA-MSRBD B1 dan B2 berupa senyawa amida. Akan tetapi produk kedua berhasil membentuk senyawa imidazolin. Kedua produk kemudian dianalisa efisiensinya sebagai inhibitor korosi untuk baja rendah karbon JIS G3123 grade SGD 400D pada larutan NaCl 1,5% yang jenuh CO2 menggunakan metode gravimetri dan elektrokimia. Inhibitor diuji dengan variasi konsentrasi 0, 5, 20, 50, dan 100 ppm. Pengujian menghasilkan efisiensi inhibisi tertinggi pada konsentrasi 100 ppm dengan nilai 85,71% dan 90,47% untuk TETA-MSRBD B1 dan B2 secara berturut-turut. Karakter adsorpsi inhibitor mengikuti model isoterm Langmuir dengan campuran fisisorpsi dan kemisorpsi yang lebih condong ke kemisorpsi.

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Low carbon steel is an alloy that is commonly used in the oil and gas industry. Its vulnerability towards corrosion supports the development of organic corrosion inhibitors which are biodegradable and easier to synthesise. This study attempts to synthesise an organic inhibitor, TETA-MSRBD, through a reflux method which is followed by a scale-up with the use of a Batch Stirred Tank Reactor using temperature variations ranging from 140°C, 150°C, 160°C, to 170°C, with a variety of stirring speeds of 700, 1000, and 1200 rpms. The initial synthesis applies an optimum condition of 150°C and 1200 rpm based on previous studies to a moderate conversion percentage of 66,85% after determining its saponification value. Further variations were applied until the highest conversion percentage was determined to be 83,43% with reaction conditions of temperature 150°C and stirring speed of 1000 rpm. Both products were extracted from unwanted side products resulting in pure TETA-MSRBD B1 and TETA-MSRBD B2. Both products were followed by characterisation with UV-Visible spectrophotometer, FTIR spectroscopy, and LC-MS. Product characterisation showed that much of the composition consists of amide intermediates yet to form imidazolines for the first product. However, the optimum product demonstrated imidazoline structures. Both products’ efficiencies as inhibitors were tested on low carbon steel JIS G3123 grade SGD 400D in a CO2-saturated 1,5% NaCl solution (saline environment) with both gravimetric and electrochemical methods. Inhibitor concentration in the corroding media ranged from 0, 5, 20, 50, to 100 ppm. These tests resulted in a high inhibition efficiency of 85,71% and 90,47% for both TETA-MSRBD B1 and TETA-MSRBD B2 respectively when inhibitor concentration was the highest at 100 ppm. The adsorption mechanism during this study follows Langmuir’s isotherm model with a mix of chemisorption and physisorption, with the latter being the more dominant."

"Tujuan dari penelitian ini adalah untuk mengevaluasi perubahan sifat mekanik, struktur mikro dan ketahanan korosi cladded API 5L X-65 UNS N08825 pada proses perbaikan pengelasan. Pengelasan dan pengelasan repair dilakukan dengan proses kombinasi yaitu gas tungsten arc welding (GTAW) dan shielded metal arc welding (SMAW). Proses pengelasan GTAW dan SMAW dilakukan dengan menggunakan filler metal ER NiCrMo3 dan E NiCrMo3. Spesimen Main sebagai bidang utama kemudian empat spesimen lainnya digerinda, dihilangkan bagian lasan pada lokasi yang berbeda dan dilas ulang dengan parameter yang sama. Spesimen ini dengan lokasi perbaikan pengelasan yang berbeda dipelajari dengan melihat sifat mekanik dan ketahanan korosi. Ketahanan korosi dilakukan menurut ASTM G48-11 metode A menggunakan larutan besi klorida untuk evaluasi korosi pitting dan ASTM A262 praktek E untuk mengevaluasi retak korosi intergranular. Uji tarik, uji Bending, ketahanan impak Charpy-V, foto makro dan uji kekerasan Vickers, SEM-EDS dilakukan. Kekerasan pada HAZ di area capping meningkat seiring dengan perbaikan yang dilakukan. Hasil pengujian tarik menunjukkan bahwa proses perbaikan las tidak berpengaruh nyata terhadap kekuatan tarik di semua lokasi perbaikan las. Nilai penurunan terbesar yaitu 0,83% terjadi pada proses perbaikan las di PTR 2. Hasil uji impak charpy-V menunjukkan penurunan nilai luas daerah yang terkena panas (FL) sebesar 10,44%. Hasil uji impak pada area base metal (WCL) memiliki nilai rata-rata paling rendah dibandingkan dengan dua daerah lainnya. FL dan FL+2. Foto SEM menunjukkan perbedaan struktural antara logam las, HAZ dan logam dasar dimana di area HAZ setiap proses perbaikan pengelasan memiliki perbedaan lebar HAZ, yang paling sempit terjadi di proses TTR yaitu 112 µm. Uji EDS menunjukkan penurunan unsur nikel dengan nilai 33,1% wt pada PTR 2 dan peningkatan unsur Fe sebesar 32,3% wt. Spesimen di daerah root lebih sensitif terhadap korosi pitting, dalam percobaan korosi pitting tidak terjadi. Pada daerah tekukan hasil pengujian ASTM A262 praktek E tidak ada retak maka tidak terjadi korosi intergranular. Pengelasan dengan menggunakan API 5L X65 cladded UNS 08825 layak untuk dilakukan konstruksi setelah dilakukan percobaan karakterisasi dan ketahanan korosi yang terbukti mengacu pada kode dan standar.

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The purpose of this study is to evaluate changes in the mechanical properties, micro structure and

the corrosion resistance of API 5L X-65 cladded UNS N08825 under repair welding. The welding

and the repair welding were conducted by combination process that is gas tungsten arc welding

(GTAW) and shielded metal arc welding (SMAW). The GTAW and SMAW welding process was

perfomed using filler metal ER NiCrMo3 and E NiCrMo3. The first specimen as main then other

four specimens weld area was ground, re-beveled on the different location and re-welded with

same parameter. Specimens of these with different location of welding repair were studied by

looking in the mechanical properties and corrosion resistance. The corrosion resistance conducted

according to ASTM G48-11 method A using ferric chloride solution for pitting corrosion

evaluation and ASTM A262 practice E to evaluated intergranular corrosion cracking. Tensile tests,

Bending test, Charpy-V impact resistance, macro photo and Vickers hardness tests, SEM-EDS

were conducted. Hardness of the heat affected zone in capping area increased as the repairs

conducted. The tensile test results show that the welding repair process does not significantly affect

the tensile strength at all welding repair locations. The biggest decrease value, which is 0.83%,

occurs in the welding repair process at the PTR 2 . location. The results of the charpy impact test

show a decrease in the value of the heat affected area (FL) by 10.44%. The impact test results in

the base metal area (WCL) had the lowest average value compared to the other two areas FL and

FL+2 are 97.8 J. The photo of the SEM shows the structural differences between weld metal, HAZ

and base metal where in the HAZ area each welding repair process have differences in the width

of the HAZ, the narrowest occurred in the TTR process 112 μm. EDS test shows decreased of the

nickel element, the value 33.1% wt in PTR 2 and increase of Fe element was 32.3% wt. The

specimen in root area is more sensitive to pitting corrosion, in experimental the pitting corrosion

was occured in capping area. In the ASTM A262 practice E intergranular corrosion test, IGC did

not occur as seen from the bending area in the result that there were no cracks. Welding using API

5L X65 cladded UNS 08825 feasible to construction after experimental for characterization and

corrosion resistance proved to referencing code and standard."

"Studi ini membahas pengaruh penambahan mangan & nitrogen dan pengerjaan dingin pada perilaku elektrokimia baja tahan karat austenitik. Mekanisme dari berbagai makalah dievaluasi dengan uji gravimetri dan pengukuran polarisasi. Morfologi produk reaksi yang dikembangkan dalam bahan dianalisis dengan spektroskopi fotoelektron sinar-X (XPS), spektroskopi dispersif energi (EDX), dan mikroskop elektron pemindaian (SEM). Berbagai baja tahan karat austenitik dengan jumlah elemen paduan yang berbeda dievaluasi pada suhu dan lingkungan larutan yang berbeda. Penambahan mangan tidak menunjukkan pengaruh yang luar biasa pada ketahanan korosi secara umum karena kemampuannya yang tidak signifikan untuk membentuk senyawa yang tidak larut. Sementara itu, mangan menunjukkan pengaruh berlawanan terhadap ketahanan korosi lokal, biasanya karena adanya inklusi MnS yang berperan sebagai inisiator pitting. Penambahan N menurunkan celah energi bebas bahan kimia antara struktur BCC dan FCC dan meningkatkan energi kesalahan susun secara lebih signifikan. Akibatnya, N dapat membuat austenit lebih stabil secara termal tetapi memiliki efek yang lebih kecil pada stabilitas mekanik. Ditemukan bahwa nitrogen meningkatkan ketahanan korosi baja. Pengaruh berbagai intensitas deformasi plastis dilakukan dengan pengerolan dingin pada temperatur yang berbeda. Hasil penelitian menunjukkan bahwa pembentukan strain-induced martensite (SIM) jelas memberikan pengaruh yang signifikan terhadap korosi dan sifat mekanik.

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The study addresses the effect of manganese & nitrogen addition and cold working on electrochemical behaviors of austenitic stainless steels.  The mechanism from various papers was evaluated by gravimetric tests and polarization measurements. The morphology of the reaction products developed in the material was analyzed by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDX), and scanning electron microscopy (SEM). Various austenitic stainless steels with different amounts of alloying elements were evaluated in different temperatures and solution environments. The addition of manganese did not show a remarkable influence on the general corrosion resistance because of the insignificant ability to form insoluble compounds. Meanwhile, manganese indicated an opposite influence on localized corrosion resistance, normally due to the existence of MnS inclusion which played as pitting initiators. The addition of N decreases the chemical-free energy gap between BCC and FCC structures and raises the stacking fault energy more significantly. Consequently, N can render austenite more thermally stable but has less effect on mechanical stability. It was found that nitrogen improved the corrosion resistance of the steel. The influence of various intensities of plastic deformation is conducted by cold rolling at different temperatures. The result shows that the formation of strain-induced martensite (SIM) obviously led to a significant effect on corrosion and mechanical properties."

"Korosi berpotensi menjadi sebuah masalah yang besar pada aplikasi yang menggunakan logam, contohnya dibidang industri minyak dan gas. Proses korosi akan mengakibatkan kerugian baik secara langsung maupun tidak langsung. Kerugian langsung seperti biaya penggantian material, biaya perawatan, overdesign, dll. Kerugian tidak langsung seperti plant shutdown, lost production, kontaminasi produk, dll. Salah satu cara untuk menangani masalah korosi ini adalah dengan menggunakan inhibitor. Penelitian ini bertujuan untuk mengetahui pengaruh teh hijau sebagai inhibitor organik ramah lingkungan pada lingkungan air laut dan mengetahui efisiensi ekstrak teh hijau terhadap waktu pengujian. Untuk mencapai tujuan dari penelitian ini, maka diadakan suatu pengujian dalam skala laboratorium dengan menggunakan baja SPCC dalam lingkungan air laut, dengan menggunakan inhibitor dari ekstrak teh hijau yang mengandung zat anti oksidan polifenol dan turunannya serta zat kafein yang diasumsikan keduanya dapat menekan laju korosi. Pengujian laju korosi menggunakan metode kehilangan berat dimana sampel baja SPCC direndam dalam air laut selama 3, 5, dan 7 hari. Dalam penelitian ini dapat disimpulkan ekstrak teh bekerja baik dilingkungan air laut karena terjadi penurunan laju korosi antara perendaman dengan inhibitor dan perendaman tanpa inhibitor terhadap lamanya waktu pengujian. Penurunan laju korosi terbesar pada hari ke-3, yaitu sebesar 32%.

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Corrosion potential to become a major problem in applications that use the metal, for example in the field of oil and gas industry. Corrosion process will result in loss either directly or indirectly. Direct losses such as material replacement costs, maintenance costs, over-design, etc.. Indirect losses such as plant shutdown, lost production, product contamination, etc.. One way to handle this problem is to use a corrosion inhibitor.

This study aims to determine the effect of green tea as an environmentally friendly organic inhibitors on the environment know the efficiency of sea water and green tea extract against time pengujian. Untuk achieve the objectives of this study, then conducted a test in a laboratory scale using SPCC steel in sea water environment, by using inhibitors from green tea extract containing anti-oxidant polyphenol and caffeine derivatives and substances which are assumed that they can suppress the corrosion rate. Tests for the corrosion rate using weight loss method in which SPCC steel samples immersed in sea water for 3, 5, and 7 days.

In this research suggested tea extracts worked well in the environment of sea water due to a decline in the rate of corrosion between immersion with inhibitor and without inhibitor immersion of the test duration. The biggest decrease in corrosion rate on day 3, ie by 32%."