Oktalda, Kelvin (2016) Analisis Perbandingan Sifat Mekanik Lasan SMAW Dan GMAW Pada Plat Baja A36 Pada Lingkungan Air Laut, Air Tawar, Dan Darat. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Perkembangan teknologi zaman sekarang mengalami kemajuan yang sangat pesat,
terutama pada teknologi konstruksi dan bangunan. Proses pembuatan kontruksi
kapal maupun bangunan lepas pantai tidak lepas dari proses pengelasan dan lambat
laun kontruksi tersebut akan mengalami kerusakan. Metode untuk reparasi kapal
umumnya sudah banyak dilakukan, berbeda dengan reparasi pada bangunan lepas
pantai yang harus ditangani secara khusus. Oleh karena itu, penelitian ini bertujuan
untuk mengetahui pengaruh jenis proses las dan salinitas terhadap perubahan sifat
mekanik weld joint material baja pada underwater welding. Pengelasan bawah air
dilakukan dengan metode SMAW dan GMAW dengan variasi salinitas 0o/oo dan
35o/oo dan didarat sebagai pembanding. Nilai kekuatan tarik dan nilai kekerasan
terbesar terdapat pada GMAW underwater welding dibandingkan dengan SMAW
underwater welding pada salinitas 35o/oo. Akan tetapi, elongation-nya lebih rendah
jika dibandingkan dengan salinitas 0o/oo dan didarat. Ini ditandai bahwa pengelasan
yang dilakukan dilingkungan laut sifat mekaniknya semakin getas dan keras karena
proses pendinginan yang cepat. Dari hasil pengamatan struktur makro pada
pengelasan SMAW dan GMAW, pada pengelasan bawah air terlihat antar layer
tidak sempurna satu sama lainnya dan terdapat juga adanya hydrogen embrittlement
dan porosity akibat proses disosiasi air selama pengelasan. Sedangkan dari hasil
pengamatan struktur mikro pada pengelasan SMAW dan GMAW, terlihat bahwa
fase pearlit pada lingkungan laut dengan salinitas 35o/oo lebih banyak jika
dibandingkan dengan pengelasan yang dilakukan diair tawar dan didarat.
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Technological developments nowadays is progressing very rapidly, particularly on
construction technology and building. The process of ship construction
manufacture as well as offshore structure can not be separated from welding process
and sooner or later the construction will have breakage. The ship repairation method
has been done daily, differ from offshore structure repairation which must be
handled specifically. Hence, this research aim to know the effect of weld process
type and the salinity towards the change of mechanical properties weld joint steel
material on underwater welding. Underwater welding conducted with SMAW and
GMAW method with salinity variation 0o/oo and 35o/oo and ashore as comparation.
The tensile strength value and the biggest hardness value could be found on GMAW
underwater welding compared to SMAW underwater welding on 35o/oo salinity.
However, the elongation is lower when it compared to 0o/oo salinity and ashore. It
could be known from the conducted welding at marine environment is the mechanic
properties more brittle and stronger because of the rapid cooling process. From the
observation of macro structures in welding of SMAW and GMAW, from
underwater welding visible on inter-layer imperfect one another and could be seen
the presence of hydrogen embrittlement and porosity which caused by water
dissociation process while welding. Whereas from the observation of micro
structures on welding of SMAW and GMAW, could be seen that martensitic phase
on marine environment with 35o/oo salinity is more than the conducted welding on
the freshwater and ashore.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 623.843 2 Okt a |
| Uncontrolled Keywords: | GMAW, Las Bawah Air, Sifat Mekanik, SMAW |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Mr. Tondo Indra Nyata |
| Date Deposited: | 21 Feb 2018 08:21 |
| Last Modified: | 27 Dec 2018 03:26 |
| URI: | http://repository.its.ac.id/id/eprint/51329 |
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