ANALISA PENGARUH VARIASI KUAT ARUS PADA PENGELASAN TIG TERHADAP KEKERASAN DAERAH HAZ ALUMUNIUM ALLOY 6063 SKRIPSI

ANALISA PENGARUH VARIASI KUAT ARUS PADA PENGELASAN TIG TERHADAP KEKERASAN DAERAH HAZ ALUMUNIUM ALLOY 6063 SKRIPSI Skripsi Yang Diajukan Untuk Melengkapi Syarat Memperoleh Gelar Sarjana Teknik

DISUSUN OLEH :

TONGIN SINAGA 110401063

DEPARTEMEN TEKNIK MESIN FAKULTAS TEKNIK UNIVERSITAS SUMATERA UTARA MEDAN 2016

Universitas Sumatera Utara

ABSTRAK Kekerasan suatu bahan sangat dipengaruhi oleh sifat mekanik dan sifat fisik tersebut pada proses penyambungan dengan menggunakan pengelasan TIG (Tungsten Inert Gas) sifat-sifat tersebut akan berubah akibat pengaruh proses pengelasan. Untuk mengkaji hal tersebut disusunlah sebuah konsep penelitian yang terdiri dari dua tahapan. Pengujian hardness test pada daerah HAZ (Heat Affected Zone) hasil pengelasan, memeriksa struktur mikro hasil pengelasan akibat variasi besaran sudut kampuh V 35º dan 60˚ dari variasi kuat arus 80 A, 90 A dan 100A pada paduan aluminium alloy 6063. Hasil dari pengujian menunjukkan pengelasan dengan variasi kuat arus 80 A, 90 A dan 100A sudut kampuh V 35º pada paduan alumunium alloy 6063 dengan kuat arus pengelasan 80 A nilai kekerasan tertinggi 82.79 kgf/mm sedangkan pada kuat arus 90 A dan 100 A nilai kekerasan yang didapat sama 82.16 kgf/mm. Dan pada paduan aluminium alloy 6063. Hasil dari pengujian menunjukkan pengelasan dengan variasi kuat arus 80 A, 90 A dan 100A sudut kampuh V 60º pada paduan alumunium alloy 6063 dengan kuat arus pengelasan 80 A nilai kekerasan tertinggi 87.25 kgf/mm sedangkan pada kuat arus 90 A dan 100 A nilai kekerasan yang didapat sama 85.98 kgf/mm. Pengujian pada pengelasan TIG (Tungsten Inert Gas) untuk paduan aluminium alloy 6063, menunjukkan Ini menunjukan bahwa semakin kuat arus berpengaruh pada nilai kekerasan daerah HAZ, dan kekerasan rata-rata yang paling baik adalah pada Kuat arus 90 Adan 100 A pada sudut kampuv tungal 35º. Kata kunci: Kekerasan, hardness test, pengelasan TIG (Tungsten Inert Gas), Sudut Kampuh, aluminium alloy 6063.

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ABSTRACT Hardness of a material is influenced by the nature of the mechanical and physical properties in the splicing process by using TIG welding (Tungsten Inert Gas) these properties will be changed due to the influence of the welding process. To look into the matter was composed of a concept study consisted of two phases. Testing hardness test on HAZ region (Heat Affected Zone) welding results, check the weld microstructure due to variations in the amount of seam V 35º angle and 60˚ of variation of the current strength of 80 A, 90 A and 100A on alloy aluminum alloy 6063. The results of the testing show strong variation welding currents of 80 A, 90 A and 100A angle of 35º to the hem V alloy 6063 with a strong aluminum alloy welding current 80 A high hardness value 82.79 kgf / mm and in the strong currents of 90 A and 100 A hardness value obtained at 82.16 kgf / mm. And aluminum alloys alloy 6063. The results of the testing show strong variation welding currents of 80 A, 90 A and 100A angle of 60º to the hem V alloy 6063 with a strong aluminum alloy welding current 80 A high hardness value 87.25 kgf / mm and in strong currents 90 A and 100 A hardness value obtained at 85.98 kgf / mm. Tests on TIG welding (Tungsten Inert Gas) for alloy aluminum alloy 6063, show This shows that the stronger the effect on the current value of the area HAZ hardness, and the average hardness of the nicest is the Strong current of 100 A at 90 Adan kampuv tungal 35º angle. Keywords: Violence, hardness test, TIG welding (Tungsten Inert Gas), Angle Kampuh, aluminum alloy 6063.

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KATA PENGANTAR

Puji syukur penulis panjatkan kehadirat Tuhan yang Maha Esa atas nikmat dan karunia yang telah diberikan kepada penulis, sehingga penulis dapat menyelesaikan skripsi dengan judul “ Pengaruh Variasi Kuat Arus Pada Pengelasan TIG Terhadap Kekerasan Daerah HAZ Alumunium Alloy 6063 ”. Skripsi ini disusun untuk memenuhi salah satu syarat dalam menyelesaikan pendidikan strata satu (S1) pada Dapertemen Teknik Mesin, Fakultas Teknik, Universitas Sumatera Utara. Penulisan skripsi ini tidak lepas dari bantuan berbagai pihak. Oleh karena itu penulis ingin menyampaikan banyak-banyak ucapan terima kasih kepada : 1.

Ir.Alfian Hamsi,MSc. Selaku pembimbing utama dan yang memberikan arahan dan saran-saran dalam penyelesaian skripsi ini.

2.

Dr.Eng.Himsar Ambarita,ST.MT. Selaku Pembanding I

3.

Ir.Terang UHSG Manik,ST.MT.Selaku Pembanding II

4.

Ir.Jaya Arjuna,M.Sc. selaku dosen pembimbing akademik selama perkuliahan.

5.

Alm. Ayahanda L.Sinaga, Alm. Ibunda R.Tamba dan Ibunda K.Tamba yang selalu sabar dan memberi semangat dalam penyelesaian skripsi.

6.

Kakak dan adik – adikku yang selalu membuat hidup lebih bersemangat.

7.

Teman teman Teknik Mesin 2011, Mesin Jaya and solidarity forever.

8.

Semua pihak yang tidak dapat disebutkan satu per satu. Penulis juga menerima segala saran dan kritik yang membangun dari semua pihak guna kesempurnaan skripsi ini. Semoga skripsi ini dapat bermanfaat. Medan, Agustus 2016 Penulis Tongin SINAGA 110401063

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DAFTAR ISI Halaman ABSTRAK .................................................................................................................................. i ABSTRAC ................................................................................................................................. ii KATA PENGANTAR .............................................................................................................. iii DAFTAR ISI............................................................................................................................. iv DAFTAR TABEL..................................................................................................................... vi DAFTAR GAMBAR ............................................................................................................... vii DAFTAR ISTILAH .................................................................................................................. xi DAFTAR NOTASI .................................................................................................................. xii BAB I. PENDAHULUAN ......................................................................................................... 1 1.1. Latar belakang ................................................................................................................. 1 1.2. Batasan Masalah .............................................................................................................. 2 1.3. Tujuan Penelitian............................................................................................................. 2 1.4. Metodologi penulisan ...................................................................................................... 2 1.5. Sistimatika Penulisan ...................................................................................................... 2 BAB II. TINJAUAN PUSTAKA .............................................................................................. 3 2.1. Pengelasan ....................................................................................................................... 3 2.1.1. Sejarah Pengelasan ................................................................................................... 3 2.1.2. Definisi Pengelasan .................................................................................................. 5 2.1.3. Klasifikasi Pengelasan .............................................................................................. 6 2.2. Pengelasan TIG ............................................................................................................ 11 2.2.1. Elektroda Pengelasan TIG ..................................................................................... 26 2.3. Desain Sambungan Las ................................................................................................ 31 2.4. Metalurgi Las ............................................................................................................... 34 2.5. Pengaruh Panas Pengelasan ......................................................................................... 35 2.6. Alumunium ................................................................................................................... 36 2.6.1. Sejarah Alumunium ................................................................................................ 36 2.6.2. Sifat-sifat dan Pemakaian Alumunium .................................................................. 37 2.7. Heat Affected Zone (HAZ) ............................................................................................ 43 2.8. Pengamatan Struktur Mikro .......................................................................................... 48 2.9. Pengujian hasil Pengelasan ........................................................................................... 50 BAB. III. METODE PENELITIAN ........................................................................................ 56 3.1. Tempat dan Waktu ........................................................................................................ 56 v

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3.1.1. Tempat .................................................................................................................... 56 3.1.2. Waktu ..................................................................................................................... 56 3.2. Metodelogi Penelitian ................................................................................................... 56 3.2.1. Metode Proses Pembuatan Spesimen ..................................................................... 57 3.3. Persiapan Alat dan Bahan ............................................................................................. 58 3.4. Proses Pengujian ........................................................................................................... 62 3.4.1. Pengujian Hardness ................................................................................................ 62 3.4.2. Struktur Mikro ........................................................................................................ 63 3.5. Diagram Alir Penelitian ................................................................................................ 64 BAB. IV. ANALISA DATA DAN PEMBAHASAN ............................................................. 65 4.1. Pendahuluan .................................................................................................................. 65 4.2. Hasil Pengujian ............................................................................................................. 65 4.3. Hasil Uji Kekerasan ...................................................................................................... 65 4.4. Hasil Fhoto Mikro ......................................................................................................... 69 BAB. V. KESIMPULAN DAN SARAN ................................................................................ 72 5.1. Kesimpulan.................................................................................................................... 72 5.2. Saran .............................................................................................................................. 72 DAFTAR PUSTAKA ............................................................................................................. xiii

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DAFTAR TABEL NO

JUDUL

HALAMAN

2.1

Penggunaan Mesin Las TIG Untuk Beberapa Logam ..................................................... 18

2.2

Jenis Arus Pengelasan TIG dan Elektroda ........................................................................ 22

2.3

Elektroda TIG ........................................................................................................................ 34

2.4

Sifat-sifat Alumunium murnu Tiinggi ................................................................................ 47

2.5

Macam-macam Aluminium dan Paduanya serta Penamaan Klasifikasi Aluminium... 48

2.6

Jenis Paduan Aluminium...................................................................................................... 50

2.7

Maca-macam Arti Kode Aluminium .................................................................................. 51

2.8

Kandungan Unsur Kimia Aluminium................................................................................. 51

2.9

Rockwell Hardness Scales.................................................................................................... 65

3.1

Unsur Kimia Aluminium Alloy 6063 ................................................................................. 73

3.2

Spesifikasi Mesin Gerinda ................................................................................................... 78

3.3

Spesifikasi Mikroskop Optik ............................................................................................... 79

3.4

Spesifikasi Mesin Las TIG Rilon 200 AC/DC .................................................................. 79

3.5

Unsur Kimia Elektroda ER5356 ......................................................................................... 80

3.6

Spesifikasi Brinell test .......................................................................................................... 81

4.1

Hasil Pengujian Hardness Test............................................................................................ 85

4.2

Hasil Kekerasan Kampuh 35˚ .............................................................................................. 88

4.3

Hasil Kekerasan Kampuh 60˚ .............................................................................................. 88

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DAFTAR GAMBAR

NO

JUDUL

HALAMAN

2.1

Sejarah Pengelasan ........................................................................................................ 3

2.2

Perkembangan Cara Pengelasan ................................................................................... 5

2.3

Proses Pengelasan Busur LasTerbungkus (SMAW)...................................................... 7

2.4

Proses Pengelasan Busur Terendam (SAW) ................................................................. 8

2.5

Proses pengelasan busur logam gas (GMAW) .............................................................. 8

2.6

Proses pengelasan berinti fluks (FCAW) ....................................................................... 9

2.7

Proses Pengelasan Busur Tungsten Innert Gas (TIG) ................................................. 10

2.8

Klasifikasi Cara Pengelasan ........................................................................................ 10

2.9

Skema Las TIG ............................................................................................................ 12

2.10

Prinsip Pengelasan TIG................................................................................................ 13

2.11

Bahan Pengisi Pengelasan TIG ................................................................................... 14

2.12

Bahan Pengisi Otomatis Pengelasan TIG .................................................................... 14

2.13

Migrasi Elektron dan Ion di Pengelsan TIG Bahan Pengisi Otomatis......................... 14

2.14

Distribusi Panas Pada TIF Pengelasan ......................................................................... 15

2.15

Daya dan Unit TIG....................................................................................................... 17

2.16

Torch Las TIG.............................................................................................................. 18

2.17

Torch TIG .................................................................................................................... 19

2.18

Gas Lens ....................................................................................................................... 20

2.19

Aliran Gas Shielding .................................................................................................... 20

2.20

Pengapian Frekuensi Tinggi ........................................................................................ 22

2.21

Pengapian Pada Metode LIFT ..................................................................................... 22

2.22

Contoh Las dengan Busur Pulsing ............................................................................... 23

2.23

Contoh Kurva AC Dimodifikasi .................................................................................. 23

2.24

Pilihan Warna Silinder ................................................................................................. 24

2.25

Flowmeter .................................................................................................................... 25

2.26

Flowmeter dengan Skala Liter ..................................................................................... 25

2.27

Pengukuran Langsung Pada Nozzel Gas ...................................................................... 26

2.28

Elektroda TIG .............................................................................................................. 27 viii

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2.29

Contoh Pembentukan Elektroda Tungsten Untuk Pengelasan DC .............................. 28

2.30

Hubungan Antara Sudut Runcing Dan Daerah Las ..................................................... 28

2.31

Titik Elektroda Datar ................................................................................................... 29

2.32

Tungssten Elektroda Untuk Pengelasan AC ............................................................... 29

2.33

Grinding Tungsten Elektrode ....................................................................................... 30

2.34

Mesin Grinda Tungsten ................................................................................................ 30

2.35

Kampuh V Las Terbuka .............................................................................................. 31

2.36

Kampuh V Las Tertutup ............................................................................................. 31

2.37

Jenis Alur Sambungan Las .......................................................................................... 34

2.38

Pembagian Daerah Las ............................................................................................... 35

2.39

Struktur Mikro Daerah Las Dari Paduan Alumunium ................................................ 36

2.40

Pengkodean Alumunium .............................................................................................. 41

2.41

Daerah Pengaruh Panas ............................................................................................... 43

2.42

Grafik Siklus Thermal Las ........................................................................................... 44

2.43

Distribusi Temperatur Pada Logam ............................................................................. 45

2.44

Perubahan Struktur Fasa ............................................................................................. 46

2.45

Heat Affected Zone ....................................................................................................... 47

2.46

Mikroskop Optik .......................................................................................................... 48

2.47

Contoh Struktur Mikro Alumunium ............................................................................ 50

2.48

Brinell Test ................................................................................................................... 52

2.49

Prinsip Fungsional Brinell ........................................................................................... 53

2.50

Tropong Hardness Tester ............................................................................................ 54

2.51

Contoh Pengamatan Tropong Brinell .......................................................................... 54

3.1

Bentuk Sudut Kampuh (a) Sudut 35º (b) Sudut 60º .................................................... 57

3.2

Spesimen Hasil Pengelasan.......................................................................................... 57

3.3

Spesimen Setelah dietsa .............................................................................................. 58

3.4

Alumunium Alloy 6063 ............................................................................................... 58

3.5

Mesin Skrap ................................................................................................................ 59 ix

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3.6

Mikroskop optik ........................................................................................................... 59

3.7

Mesin Las TIG ............................................................................................................. 60

3.8

Kawat Elektroda ER 5356 ........................................................................................... 61

3.9

Hardness Test............................................................................................................... 62

4.1

Grafik Nilai Rata-rata Indentor ................................................................................... 66

4.2

Grafik Nilai BHN Kampuh 35˚.................................................................................... 68

4.3

Grafik Nilai BHN Kampuh 60˚.................................................................................... 68

4.5

Mikro Struktur 80 A..................................................................................................... 69

4.6

Mikro Struktur 90 A..................................................................................................... 70

4.7

Mikro Struktur 100 A................................................................................................... 70

4.8

Mikro Struktur 80 A..................................................................................................... 70

4.9

Mikro Struktur 90 A..................................................................................................... 71

4.10

Mikro Struktur 100 A................................................................................................... 71

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DAFTAR ISTILAH

NO Iistilah

Arti

1

AWS

American Welding Society

2

ASME

American Society of Mechanical Engineers

3

API

American Petroleum Institute

4

Al-Mg

Aluminium - Magnesium

5

DPP

Daerah Pengaruh Panas

6

FCAW

Fluks Cored Arc Welding

7

GMAW

Gas Metal Arc Welding

8

GTAW

Gas Tungsten Arc Welding

9

HAZ

Heat Affected Zone

10

NDT

Non Destructif Test

11

SMAW

Shielded Metal Arc Welding

12

SAW

Sumarged Arc Welding

13

TIG

Tungsten Inert Gas

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DAFTAR NOTASI Simbol

Besaran

Satuan

F

Total Beban .............................................................................................................. (kgf)

1

panjang Indentor ..................................................................................................... (mm)

I

Kuat Arus ................................................................................................................... (A)

F0

Beban Minor ............................................................................................................ (kgf)

F1

Beban Mayor ............................................................................................................ (kgf)

d

Impresion Diameter ................................................................................................ (mm)

D

Diameter Bola ......................................................................................................... (mm)

P

Load ......................................................................................................................... (kgf)

HB

Brinell result ............................................................................................................ (HB)

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