Wibowo, Prasetyo (2015) Analisis pengaruh preheat atau pemanasan awal terhadap hasil pengelasan ulang aluminium 5083 di tinjau dari sifat mekanik dan metalurgi pada lambung kapal. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Aluminium dan paduan aluminium termasuk logam ringan yang memiliki kekuatan
tinggi, tahan terhadap karat, konduktor listrik yang cukup baik dan juga lebih ringan dari besi
atau baja. Preheat merupakan metode perlakuan panas yang dilakukan dalam pengelasan.
Tujuan utama dari preheat adalah untuk mengurangi perbedaan temperatur pada daerah
pengelasan. Pengelasan ulang dapat terjadi pada material yang mengalami replating akibat
kesalahan dalam pekerjaan di lapangan. Pengelasan ulang akan mengakibatkan perubahan
terhadap sifat-sifat mekanik dan struktur mikronya.
Dalam tugas akhir ini dilakukan pengelasan ulang sebanyak 3 kali dengan perlakuan
preheat. Suhu preheat sebesar 80oC dan suhu interpass sebesar 150oC. Proses pengelasan
yang digunakan untuk pengelasan aluminium adalah gas metal arc welding (GMAW) atau
yang lebih dikenal dengan las MIG. Kemudian dilakukan pengujian yang mencakup: uji tarik,
uji kekerasan, dan uji struktur mikro.
Dari hasil pengujian dapat diketahui nilai kuat tarik tertinggi sebesar 243.86 N/mm2
pada 1 kali pengelasan (no repair) dan nilai kuat tarik terendah sebesar 161.24 N/mm2 pada 4
kali pengelasan (3 x repair). Nilai kekerasan tertinggi terdapat pada daerah base metal dengan
spesimen 1 kali pengelasan (no repair) sebesar 112.3 HV dan nilai kekerasan terendah
terdapat pada daerah weld metal dengan spesimen 4 kali pengelasan (3 x repair) sebesar 65.5
HV. Dari hasil uji metalografi dapat diamati bahwa semakin banyak jumlah repair yang
diterima maka jumlah partikel Mg2Si pada daerah HAZ akan semakin besar dan menggumpal,
sedangkan jumlah partikel Mg2Al3 pada daerah weld metal mengalami penurunan.
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Aluminium and aluminium alloy is a lightweight metal that has high strength, resistant
to corrosion, electrical conductor that are quite good and also lighter than iron or steel.
Preheat is a method of heat treatment carried out on welding. The main purpose of the preheat
is to reduce difference of temperature on welding zone. Reweld process could be occured on
the material which had been replating because of the fault on the work in the field. Reweld
process will changes the mechanical properties and microstructure of the material.
This final project is conducted with reweld process until three times with preheating.
Temperature of preheat is 80oC and temperatur of interpass is 150oC. Welding process for
aluminium is gas metal arc welding (GMAW) or known as MIG welding. Testing includes:
tensile test, hardness test, and microstructure test.
Test results showed that the highest value of tensile strength was 243.86 N/mm2 on
welding until one times (no repair) and the lowest value of tensile strength was 161.24 N/mm2
on welding until four times (3 x repair). The highest value of hardness was located on base
metal zone which the specimen have a weld until one times (no repair) was 112.3 HV and the
lowest value of hardness is located on weld metal zone which the specimen have a weld until
four times (3 x repair) was 65.5 HV. From metallography test can be observed that the higher
number of repairing process in material so that the bigger Mg2Si particle in HAZ zone will be
clumped, while Mg2Al3 particles in weld metal zone are getting decreased.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSPe 623.843 2 Wib a |
| Uncontrolled Keywords: | Aluminium 5083, jumlah repair, preheat, kuat tarik, metalografi, kekerasan. |
| Subjects: | T Technology > TN Mining engineering. Metallurgy > TN879.6 Welding |
| Divisions: | Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis |
| Depositing User: | Mr. Marsudiyana - |
| Date Deposited: | 18 Nov 2019 03:37 |
| Last Modified: | 18 Nov 2019 03:37 |
| URI: | http://repository.its.ac.id/id/eprint/71842 |
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