Nawawi, Muhammad Khoirul Anwar (2018) Pengaruh Variasi Laju Aliran Gas Pada Pengelasan GTAW (Gas Tungsten Arc Welding) Pada Baja ST 42 Terhadap Cacat Las, Lebar HAZ Dan Kekerasan. Diploma thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Masalah yang terjadi pada pengelasan GTAW (Gas Tungsten Arc Welding) adalah gas pelindung yang digunakan untuk melindungi busur dan logam cair dari kontaminasi oksigen dan nitrogen yang ada pada atmosfer.Jika laju aliran gas pelindung tidak tepat dalam las logam cair maka akan menghasilkan cacat las.
Pada penelitian ini ,perlakuan yang diberikan oleh peneliti adalah pengelasan dengan variasi laju aliran gas. Pengelasan dilakukan dengan metode GTAW(Gas Tungsten Arc Welding) pada bahan baja ST 42 dengan filler ER 70S-6 dengan kampuh V tunggal 60°.Variasi laju aliran gas yang digunakan dalam penelitian ini adalah laju aliran gas 10 liter/menit, 15 liter/menit dan 20 liter/menit, kemudian diuji dengan menggunakan uji radiografi, makro etsa dan kekerasan .
Pada hasil pengujian radiografi ,jenis cacat yang paling sedikit terdapat pada material hasil lasan dengan laju aliran gas 15 liter/menit yaitu cacat tungsten inclusion dan porosity dibanding laju aliran gas 10 liter/menit yaitu cacat porosity, incomplete fusion, undercut dan laju aliran gas 20 liter/menit yaitu cacat porosity, incomplete fusion, tungsten inclusion, undercut .Untuk hasil pengujian makro etsa didapat lebar HAZ terbesar terdapat pada hasil lasan laju aliran gas 20 liter/menit. Pada laju aliran gas 15 liter/menit mengalami penurunan lebar HAZ tetapi pada laju aliran 10 liter/menit mengalami kenaikan lebar HAZ. Pada hasil pengujian kekerasan pada laju aliran gas 10 liter/menit, 15 liter/menit dan 20 liter/menit cenderung mengalami kenaikan dari base metal sampai weld metal. Nilai kekerasan tertinggi terdapat pada laju aliran gas 20 liter/menit yaitu Base metal 76,479 HRB, HAZ 82,708 HRB, dan Weld metal 86,854 HRB.
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Problems that occur in GTAW (Gas Tungsten Arc Welding) welding is a protective gas used to protect arc and liquid metal from the contamination of oxygen and nitrogen present in the atmosphere. If the flowrate of protective gas is not right in the welding of molten metal it will produce a weld defects.
In this research, the treatment given by the researcher is welding with variety of gas flowrate. Welding is done by GTAW (Gas Tungsten Arc Welding) method on ST 42 steel material with ER 70S-6 filler with single V hem 60°. The variety of the gas flow rate used in this research is the gas flow rate of 10 liters / minute, 15 liters / minute and 20 liters / minute, then tested using radiographic tests, macro etching and hardness.
In the radiographic test results, the least defective type found in welded material with gas flow rate of 15 liters / minute is tungsten inclusion defect and porosity compared to 10 liters / minutes gas flow rate is porosity defect, incomplete fusion, undercut and gas flow rate 20 liter / min that is porosity defect, incomplete fusion, tungsten inclusion, undercut. For macro etch test result obtained the largest width of HAZ is in result of welding gas flow rate 20 liter / minute. At a gas flow rate of 15 liters / min decreases the width of HAZ but at a flow rate of 10 liters / min increases HAZ width. In the results of hardness testing at gas flow rate 10 liters / minute, 15 liters / minute and 20 liters / min tends to increase from base metal to weld metal. The highest hardness value is at gas flow rate 20 liter / minute that is Base metal 76,479 HRB, HAZ 82,708 HRB, and Weld metal 86,854 HRB.
| Item Type: | Thesis (Diploma) |
|---|---|
| Uncontrolled Keywords: | Pengelasan, GTAW, Variasi Laju Aliran Gas, Baja ST 42 |
| Subjects: | T Technology > TS Manufactures > TS227 Welding. |
| Divisions: | Faculty of Vocational > Mechanical Industrial Engineering |
| Depositing User: | Muhammad Khoirul Anwar Nawawi |
| Date Deposited: | 02 Aug 2021 22:11 |
| Last Modified: | 02 Aug 2021 22:11 |
| URI: | http://repository.its.ac.id/id/eprint/57148 |
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