Nilai Ketangguhan dan Bentuk Struktur Mikro dari Perubahan Kuat Arus pipa Spiral

Submerged Arc Welding is a welding process used for fabrication of pipes, for example spiral welded pipes. The technique can be operated automatically and has a high reliability in many various welding aplication. Some factor affecting the strength of weld metals are heat input, current, chemical composition of filler and flux, welding speed and cooling rate. The purpose of this reased is to obtaine micro structure containing acicular ferrite which give high toughness of the submerged arc welded pipes. Material used in this experiment was API 5L X-52 spiral welded steel pipes, Welding was carried out using voltage of 35 volt, welding speed of 13,67 mm/s whereas current was varied, namely 800 Amper, 825 Amper, 850 Amper, 875 Amper and 900 Amper. A series of mechanical properties test were carried out including micro structure form and toughness. The result show that, an increase in weld current make increased the amount of acicular ferrite and toughness number is increase

Metolazone compound as corrosion inhibitor for API 5L X-52 steel in hydrochloric acid solution

The aim of this research is to evaluate the inhibitive effect of metolazone on API 5L X-52 steel in 2 M HCl solution using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques within a temperature range of 303 to 323 K. Scanning electron microscopy (SEM) was also employed to study the morphology of the corroded coupons in 2 M HCl solution and in the presence of the inhibitor. The efficiency of the inhibition depends on the concentration of metolazone and reaction system temperature. The maximum inhibition efficiency values were 92.7 and 90.7%, respectively, for both EIS and polarization techniques at the temperature of 303 K. The electrochemical impedance spectra (EIS) studies reveal that the process of inhibition is through charge transfer. Potentiodynamic polarization (PDP) studies showed that metolazone is mixed-type inhibitor.  The metolazone adsorption characteristics on API 5L X-52 steel surface was found to be spontaneous and obeyed Langmuir adsorption isotherm and the mechanism of adsorption suggest chemisorptions. The inhibition efficiency of metolazone drug obtained by electrochemical methods was in good relationship with each other.                     KEY WORDS: Metolazone drug, API 5L X-52 Steel, SEM, Electrochemical, Corrosion inhibition   Bull. Chem. Soc. Ethiop. 2020, 34(2), 407-418 DOI: https://dx.doi.org/10.4314/bcse.v34i2.1

Perilaku Laju Rambatan Retak Fatik Sambungan Spiral Las Busur Rendam Pipa Baja API 5L X-52 yang Mengalami Perlakuan Panas Stress Relief.

Spiral welded steel pipes are widely used for oil/gas (API) transmission. Such pipes are usually produced by forming hot-rolled coil (HRC) steels into tubular products and welding is performed along spirally joining lines using a submerged arc welding (SAW) process. For structural applications, weld metals for API 5L X-52 steel pipes must have high strength, good impact toughness and high resistance to fatigue crack growth. The present investigations aims to study effects of stress relief heat treatment on mechanical properties of submerged arc spiral welded API 5L X-52 steel pipes in particular fatigue crack growth behaviour. Experiments were carried out by heating submerged arc steel weld metals of API 5L X-52 steel pipes to various temperatures, namely 400, 500 and 600 °C for 3 hours. Subsequently, a sequence of tests were conducted including microstructural examination, hardness test, tensile test and fatigue crack growth test. Results of this investigation show that stress relief heat treatment is proved to improve resistance to crack growth. At low AK, the weld metal which is heat treated at 600 °C reveals the highest resistance to fatigue marked its lowest value of A. However, for higher AK, the n value of the weld metal heat treated at 500 °C is the lowest suggesting that this weld metal has optimum resistance to fatigue crack growth. Keywords : API 5L X-52 steel pipes, submerged arc welding and fatigue crack growt

Corrosion Rate of Carbon Steel for Flowline and Pipeline as Transmission Pipe in Natural Gas Production with Co2 Content

The purpose of this research is to investigate the corrosion rate of carbon steel as flowline and pipeline in natural gas production with CO2 content. The influence of variety of conditions that represent the actual conditions in practice such as CO2 partial pressure and solution composition, particularly NaCl percentage were performed. Research conducted by polarization test and simulation methods using PREDICTTM software. The result of this research is used to illustrate the level of corrosion rate of typical carbon steel i.e. API 5L X-52 occurred in natural gas pipelines due to the effect of dissolved CO2. From the experiments obtained that corrosion rate of steel in environments containing CO2 ranged between 15-28 mpy. This high corrosion rate observed could severely damage natural gas transmission flowline and pipeline. The result of this research is the first step, as an input for prevention efforts, to prevent leakage of flowline and pipeline due to corrosion of CO2 which appropriate with the lifetime that has been designed

Pengaruh Las Tahanan Listrik terhadap Kekuatan Mekanis Pipa Baja Api 5l – X52 ( 24” X 12.70 Mm )

Peranan teknologi pengelasan dalam mendukung berbagai sektor industri terutama dalam bidang fabrikasi dirasakan semakin meningkat dimasa-masa mendatang. Hal ini dirasakan dengan semakin meningkatnya permintaan terhadap berbagai jenis kontruksi dengan persyaratan kualitas semakin tinggi. Maka untuk meningkatkan kualitas dibutuhkan syarat mutu baik bahan baku yang berkualitas maupun proses produksi dengan teknologi yang canggih dan sumber daya manusia yang terampil.Mutu sambungan las biasanya diukur dari komposisi kimia dari logam, kekuatan dan keuletan serta struktur mikro yang terbentuk pada sambungan las.untuk melakukan pengelasan yang berkwalitas tinggi PT. BAKRIE PIPIE INDUSTRIES menggunakan metode Pengelasan Kampuh Kontinyu ( Continuous Seam Welding ) dan untuk mengetahui kekuatan dari pipa baja API 5L X-52 ( 24” X 12.70mm) maka dilakukan pengujian yang meliputi : Pengujian Tarik, Kekerasan metode Vickers dan Struktur Mikro dengan membandingkan kekuatan daerah HAZ dan Base Metal serta Fusion Line sesuai dengan standar yang telah ditetapkan.Berdasarkan pengujian secara keseluruhan, menunjukkan bahwa data hasil pengujian sesuai standar. Untuk pengujian tarik menunjukkan bahwa Kuat Tarik daerah Weld lebih tinggi dari Transe ini dikarenakan Post Weld Heat - treatment, ( perlakuan panas setelah pengelasan ) sangat efktif. Untuk pengujian kekerasan daerah Base Metal yang paling keras, karena tidak terkena perlakuan panas

PENGUNGKAPAN REGIONAL INTELLECTUAL CAPITAL (RIC) UNTUK MENUNJANG UPAYA PENGENTASAN KEMISKINAN (NO POVERTY)

This research aims to determine the disclosure of Regional Intellectual Capital (RIC) regarding poverty alleviation efforts (No Poverty). The research method used in this research is a qualitative method with secondary data in the form of city/district reports in figures for the Surabaya and Bojonegoro residencies during 2020-2022. The data analysis technique in this research uses content analysis by providing a checklist of RIC items disclosed on the official website of the Central Statistics Agency (BPS) for each city or district in the Residency of Surabaya and Bojonegoro for 2020-2022. Disclosure of RIC information is weighted according to projections using a numerical code which is then grouped based on six RIC indicators and a quality assessment is carried out using a six ways numerical coding system which is then linked to efforts to eradicate poverty (no poverty) which is the main goal in the Sustainable Development Goals (SDGs). The research results show that the disclosure of RIC in Surabaya and Bojonegoro Residencies during 2020-2022 is quite good and has contributed to alleviating regional povert

Pemantauan dan penilaian retak lesu ke atas talian paip gas dengan menggunakan teknologi pancaran akustik

Fenomena kegagalan lesu dalam talian paip gas sewajarnya dikesan sejak peringkat awal lagi kerana akibatnya yang sangat buruk, dan aplikasi teknologi pancaran akustik dijangka sesuai untuk tujuan mi. Objektif utama projek mi adalah untuk mengkaji korelasi antara isyarat pancaran akustik dengan peringkat-peringkat tertentu dalam mekanisme lesu bagi keluli talian paip API 5L X70 yang jarang ditemui sebelum mi. Bagi mencapai objektif tersebut, ujian makmal telah dilakukan dan dibahagikan kepada dua bahagian iaitu ujian tegangan dan ujian lesu. Ketika ujian lesu, spesimen dikenakan tegasan berkitar balikan sepenuhnya dengan frekuensi bebanan 5Hz dan amplitud tegasan sebanyak 65%, 60%, 58% dan 53% daripada tegasan muktamad. Isyarat pancaran akustik turut dicerap daripada kedua-dua bahagian ujian tersebut. Selain ujian makmal, ujian lapangan turut dilakukan dengan mencerap isyarat pancaran akustik daripada bahagian simpang talian paip gas yang sedang beroperasi untuk tujuan perbandingan. Berdasarkan keputusan ujian tegangan yang dilakukan terhadap keluli API 5L X70, didapati bahawa nilai tegasan alah, tegasan muktamad clan terikan keseluruhan yang dicatatkan masing-masing adalah 637.8 MPa, 706.5 MPa, dan 0.246 mmlmm. Hasil kajian korelasi isyarat pancaran akustik dengan lengkung tegasan-terikan bagi keluli API 5L X70 telah menunjukkan bahawa aktiviti pancaran akustik sangat aktif pada ubah bentuk e1astik. Korelasi isyarat pancaran akustik dengan ujian lesu bagi spesimen yang dikenakan tegasan amplitud yang berlainan telah menunjukkan bahawa trend taburan aktiviti pancaran akustik yang dicerap dapat dibahagikan kepada tiga peringkat. Ketiga-tiga peringkat mi sangat dipengaruhi oleh fenomena pengerasan berkitar dan perlembutan berkitar yang berlaku semasa beban berkitar dikenakan. Analisis ciri-ciri pancaran akustik bagi isyarat-isyarat yang terjana pada ketiga - tiga peringkat di dalam mekanisme lesu menunjukkan bahawa nilai frekuensi dominan bagi isyarat-isyarat domain frekuensi daripada mekanisme lesu dengan operasi sebenar talian paip telah menunjukkan perbezaan. Nilai frekuensi dominan yang dicatatkan pada peringkat kedua dan ketiga dalam mekanisme lesu masing-masing berada pada julat antara 314 kHz hingga 364 kHz, dan 312 kHz hingga 380 kHz. Manakala nilai frekuensi dominan bagi isyarat domain frekuensi daripada ujian lapangan berjulat antara 50.05kHz hingga 68.36 kHz. Namun, perbandingan nilai frekuensi dominan bagi isyarat-isyarat yang dicerap pada ketiga-tiga peringkat semasa mekanisme lesu tidak menunjukkan perbezaan yang jelas. Keputusan analisis parameter statistik bagi isyarat-isyarat domain masa pancaran akustik daripada ujian lesu dan ujian lapangan menunjukkan bahawa nilai kurtosis hanya dapat memberikan perbezaan antara isyarat yang dicerap daripada ujian lapangan dan peringkat retak sahaja. Oleh itu analisis komponen utama telah diaplikasikan dan analisis mi ditemui berupaya untuk membezakan isyarat-isyarat domain frekuensi daripada ketiga-tiga peringkat semasa mekanisme lesu dan operasi sebenar talian paip gas. Modifikasi persembahan keputusan analisis komponen utama dengan mengaplikasikan plot dendrogram telah menunjukkan perbezaan kelompok isyarat pancaran akusfik daripada peringkat yang berbeza dengan lebih jelas. Isyarat pancaran akustik yang dicerap daripada lapangan turut berada pada kelompok yang sangat berbeza daripada kelompok isyarat-isyarat daripada mekanisme lesu. Secara keseluruhannya, dapat dirumuskan bahawa korelasi isyarat pancaran akustik dengan mekanisme lesu dapat dijadikan panduan di dalam memantau dan menilai fenomena lesu dalam talian paip semasa operasi

Design of a four-point bend test for ultra-low cycle fatigue of pipelines under inelastic bending

This master thesis is situated in the research domain dealing with the ductile failure of pipelines under extreme loading conditions. It is part of an umbrella research aiming to develop innovative experimental and computational methodologies to simulate fracture of steel structural elements under ultralow cycle fatigue. The focus of this study is on steel pipeline applications. The objective of this thesis is to design a large-scale four-point bend test setup to cyclically bend pipes. The feasibility of instrumentation will be evaluated using small scale test specimens. In this paper some ideas, constraints and opportunities for the design are considered, based on a literature review of several test setups for other applications. The design parameters have been calculated to compose the design windows and an initial overview of the possible instrumentation is given

Mokro podvodno zavarivanje čelika visoke čvrstoće

Cilj ovog rada bilo je ispitati mogućnosti mokrog podvodnog zavarivanja čelika za cjevovode API 5L X80. U uvodnom dijelu navedene su sve moderne tehnike mokrog i suhog podvodnog zavarivanja koje se danas koriste u off-shore industriji. Detaljno je obrađena fizika procesa, problematika, i svi tehnički aspekti tehnike mokrog podvodnog REL zavarivanja. Jedno poglavlje posebno je posvećeno razvoju čelika povišene čvrstoće te njihovoj primjeni u praksi, s naglaskom na off-shore industriju. Eksperimentalni rad proveden je u Laboratoriju za zavarivanje, Fakulteta strojarstva i brodogradnje. Iz osnovnog materijala API 5L X80 izrađene su epruete na kojima se izvodilo navarivanje. Kao dodatni materijal za navarivanje koristile su se dvije vrste elektroda za podvodno zavarivanje, Thyssen \Nautica Ø3,2 mm i Lastek Ø4 mm elektroda. \Na dobivenim navarenim spojevima ispitana je tvrdoća te je izvršena mikroanaliza, kako bi se utvrdila kvaliteta dobivenih navarenih spojeva, a time i primjenjivost mokrog podvodnog zavarivanja za API 5L X80 čelik. Isti postupak ponovljen je na konstrukcijskom čeliku S235 u cilju usporedbe dobivenih rezultata sa rezultatima API 5L X80 čelika