Struktur offshore termasuk anjungan pengeboran minyak, pipa, dan platform akan mengalami kegagalan pada elemen-elemennya selama operasi dan kemungkinan-kemungkinan yang tidak diprediksi seperti badai dan benturan. Metode perbaikan akan dibutuhkan seperti pengelasan bawah air (underwater welding). Dua kategori utama pada teknik pengelasan di dalam air adalah pengelasan basah (Wet Underwater welding) dan pengelasan kering (Dry Underwater Welding). Melalui penelitian ini di kaji pengaruh variasi temperatur pada wet underwater welding terhadap perubahan kekuatan tarik, kekerasan dan struktur mikro pada material pipa API 5L Grade X46 studi kasus di perairan Ujung Pangkah, Gresik. Pengelasan bawah air dilakukan dengan metode SMAW wet welding dengan sambungan las bevel single v-groove pada posisi 1G dengan memvariasikan temperatur air laut yang digunakan, yaitu: 25oC dan 31oC. Melalui pengujian tarik diperoleh kekuatan tarik material di darat masih lebih tinggi dibandingkan dengan kekuatan tarik di bawah air dengan temperatur 31oC dan 25oC dengan penurunan kekuatan tariknya berturut-turut sebesar 28,23%, dan 46,42%. Nilai kekerasan material yang dilas di bawah air dengan temperatur 25oC lebih besar dibanding kekerasan material yang dilas di bawah air dengan temperatur 31oC dan di darat, dengan kenaikan nilai kekerasan rata-rata pada temperatur 25oC dan 31oC berturut-turut sebesar 12,76% dan 5, 37%. Pada pengamatan struktur mikronya, tampak bahwa hasil pengelasan baik di darat maupun di bawah air pada temperatur 25oC dan 31oC tidak tampak adanya fase martensit. Hal ini karena dengan kandungan karbon yang rendah sangat sulit untuk membentuk fase martensit. Dari analisa tersebut, maka dapat disimpulkan bahwa pengelasan bawah air untuk perbaikan pipa akibat kerusakan pipa maupun kebocoran pipa di Ujung Pangkah, Gresik, yang tepat adalah pada saat temperatur airnya mencapai 31oC atau pada saat temperatur maksimum di perairan tersebut.
Alt. Description
Offshore structure including pipeline and platform, will get damage or failure on its elements and any possibilities which cannot be predicted like storm and collision. Repairing method will be required like underwater welding. Two main catagories of underwater welding are wet underwater welding and dry underwater welding. Through this research was studied the influence of temperature toward tensile strength, hardness, and microstructure changes of wet underwater welding of pipe material API 5L Grade X46, case study at Ujung Pangkah, Gresik. Underwater welding was conducted with SMAW wet welding process with single bevel v-groove of weld joint and 1G of weling position with variation of water temperature, that are : 25oC and 31oC. From the tensile test result showed that tensile strength value of material which was welded in air is greater than material which was welded underwater with 25oC and 31oC of temperature, with decreasing of tensile strength value successively about 46,21 % and 28,23%. The hardness value of material which was welded underwater with 25oC of temperature is greater than material which was welded underwater with 31oC of temperature and in air, with increasing of mean hardness value both with 25oC and 31oC successively about 12,67% and 5,67%. From the microstructure observation, showed that the welding result both in air and underwater with with 25oC and 31oC of temperature, not yet been formed martensit phase. This is because, with low carbon content of base metal (max. 0,28%C) and electrode (max. 0,12%C) is difficult to form martensit phase. From the analysis, can be concluded that the correct underwater welding for repairing damage pipe or leakage pipe at Ujung Pangkah, Gresik, is when the water temperature reach 31oC or at maximum temperature in that water territory
Contributor | : |
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Date Create | : | 11/09/2009 |
Type | : | Text |
Format | : | pdf. |
Language | : | Indonesian |
Identifier | : | ITS-Undergraduate-3100009035402 |
Collection ID | : | 3100009035402 |
Call Number | : | RSKe 671.52 Set p |
Source :
Undergraduate Theses of Ocean Engineering, RSKe 671.52 Set p, 2009
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ITS Community Only
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Copyright @2009 by ITS Library. This publication is protected by copyright and permission should be obtained from the ITS Library prior to any prohibited reproduction, storage in a retrievel system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to ITS Library
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