DAFTAR ISI Halaman Judul......................................................................................................... i Lembar Pengesahan Dosen Pembimbing ................................................................ ii Lembar Pengesahan Dosen Penguji ....................... Error! Bookmark not defined. persembahan ........................................................................................................... iv Halaman Motto........................................................................................................ v Kata Pengantar ....................................................................................................... vi Abstrak ................................................................................................................. viii Abstract .................................................................................................................. ix Daftar Isi.................................................................................................................. x Daftar Tabel .......................................................................................................... xii Daftar Gambar ...................................................................................................... xiii Daftar Persamaan .................................................................................................. xv Daftar lampiran .................................................................................................... xvi Bab I Pendahuluan .................................................................................................. 1 1.1
Latar Belakang ......................................................................................... 1
1.2
Rumusan masalah ..................................................................................... 2
1.3
Batasan Masalah ....................................................................................... 2
1.4
Tujuan Penelitian ...................................................................................... 2
1.5
Manfaat Tugas Akhir ................................................................................ 3
1.6
Sistematika Penulisan ............................................................................... 3
Bab II Kajian pustaka .............................................................................................. 4 2.1
Tinjauan Pustaka ...................................................................................... 4
2.2
Pengelasan .............................................................................................. 10
2.2.1
Jenis-Jenis Pengelasan .................................................................... 11
2.2.2
RSW (Resistance Spot Welding) ..................................................... 12
2.2.3
Aplikasi RSW ................................................................................. 14
2.3
Metalurgi Las ......................................................................................... 14
2.4
Material .................................................................................................. 15
2.4.1
Baja Karbon .................................................................................... 15
2.4.2
Baja tahan karat ............................................................................... 17
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2.4.3 2.5
Baja Tahan Karat JSL AUS ............................................................ 20
Korosi ..................................................................................................... 21
2.5.1
Reaksi Elektro Kimia ...................................................................... 23
2.5.2
Korosi Dalam Lingkungan Yang Mengandung Oksigen ................ 24
2.5.3
Korosi Baja Karbon Rendah ........................................................... 24
2.5.4
Korosi Baja Tahan Karat ................................................................. 25
Bab III Metodologi Penelitian............................................................................... 26 3.1
Alur Penelitian ........................................................................................ 26
3.2
Pelaksanaan Penelitian ........................................................................... 27
3.2.1
Rancangan Sambungan Las ............................................................ 27
3.2.2
Material Penelitian .......................................................................... 28
3.2.3
Peralatan .......................................................................................... 28
3.2.4
Pengelasan RSW (Resistance Spot Welding) .................................. 29
3.3
Pengujian Material RSW ........................................................................ 31
3.3.1
Pengujian Tarik Geser ..................................................................... 31
3.3.2
Pengujian Foto Mikro ..................................................................... 32
3.3.3
Pengujian Kekerasan (Vickers Microhardness) .............................. 33
3.3.4
Pengujian Korosi ............................................................................. 34
Bab IV Hasil dan Pembahasan .............................................................................. 36 4.1
Pengujian Tarik-Geser (Tensile-Shear) .................................................. 36
4.2
Pengamatan Foto Makro ........................................................................ 40
4.3
Pengamatan Foto Mikro ......................................................................... 41
4.3.1
Pengamatan Foto Mikro Daerah Logam Induk ............................... 41
4.3.2
Daerah HAZ (Heat Effected Zone) ................................................. 42
4.3.3
Daerah Las (Weld Nugget) .............................................................. 43
4.4
Pengujian Kekerasan Mikro Vickers ...................................................... 44
4.5
Pengujian Korosi .................................................................................... 46
Bab V Penutup ...................................................................................................... 49 5.1
Kesimpulan ............................................................................................. 49
5.2
Saran atau Penelitian Berikutnya ........................................................... 50
Daftar Pustaka ....................................................................................................... 51 Lampiran ............................................................................................................... 52
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DAFTAR TABEL Tabel 2-1 Perbandingan komposisi kimia JSL AUS dan AISI 304 ...................... 21 Tabel 3-1 Jumlah Pengelasan Tiap Parameter Las ............................................... 27 Tabel 3-2 Komposisi Kimia Baja Karbon Rendah ............................................... 28 Tabel 3-3 Komposisi Kimia Stainless Steel JSL AUS .......................................... 28 Tabel 3-4 Alat uji yang digunakan ........................................................................ 29 Tabel 3-5 Parameter tegangan pada mesin las titik ............................................... 29 Tabel 3-6 Spesifikasi mesin las titik ..................................................................... 29 Tabel 3-7 Parameter pengujian Vickers ................................................................ 34 Tabel 4-1 Hasil pengujian kekerasan VHN .......................................................... 45
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DAFTAR GAMBAR Gambar 2-1 Diameter kritis berdasarkan model patah interfacial .......................... 7 Gambar 2-2 Diameter kritis untuk uji tarik dan uji tarik-geser............................... 8 Gambar 2-3 Prediksi gagal PF dan IF berdasarkan tebal material .......................... 9 Gambar 2-4 Pengaruh arus listrik terhadap jenis kegagalan sambungan las ........ 10 Gambar 2-5 Skema definisi proses pengelasan ..................................................... 11 Gambar 2-6 Bagan klasifikasi proses pengelasan ................................................. 11 Gambar 2-7 Pengelasan RSW (Resistansi Spot Welding)..................................... 12 Gambar 2-8 Metalurgi pengelasan titik................................................................. 14 Gambar 2-9 Struktur mikro austenitik .................................................................. 18 Gambar 2-10 Struktur mikro Ferritic .................................................................... 19 Gambar 2-11 Struktur mikro Martensitic .............................................................. 19 Gambar 2-12 Struktur mikro Duplex .................................................................... 20 Gambar 3-1 Diagram Alir Proses Penelitian ......................................................... 26 Gambar 3-2 Bentuk spesimen yang dilas .............................................................. 27 Gambar 3-3 Saat pengelasan ................................................................................. 30 Gambar 3-4 Mesin uji tarik ................................................................................... 32 Gambar 3-5 Alat uji foto mikro ............................................................................ 33 Gambar 3-6 Alat uji foto makro ............................................................................ 33 Gambar 3-7 Alat Uji Kekerasan Vickers Microhardness ..................................... 34 Gambar 3-8 Spesimen dipotong berbentuk lingkaran ........................................... 35 Gambar 4-1 Patahan pada tiap spesimen .............................................................. 36 Gambar 4-2 Perbandingan nugget dengan parameter las ...................................... 37 Gambar 4-3 Perbandingan nugget dengan parameter las ...................................... 37 Gambar 4-4 Perbandingan kapasitas dukung dengan parameter las ..................... 38 Gambar 4-5 Perbandingan kapasitas dukung dengan parameter las ..................... 38 Gambar 4-6 Perbandingan perendaman dengan diameter nugget kritis ............... 39 Gambar 4-7 Perbandingan perendaman dengan tegangan listrik kritis ................ 39 Gambar 4-8 Foto makro ........................................................................................ 40 Gambar 4-9 Foto mikro daerah logam induk pada baja karbon............................ 41 Gambar 4-10 Foto mikro daerah logam induk pada baja tahan karat JSL AUS ... 42
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Gambar 4-11 Foto mikro daerah HAZ pada baja karbon ..................................... 42 Gambar 4-12 Foto mikro daerah HAZ pada baja tahan karat JSL AUS ............... 43 Gambar 4-13 Foto mikro daerah las pada baja karbon ......................................... 43 Gambar 4-14 Foto mikro daerah las pada baja tahan karat JSL AUS .................. 44 Gambar 4-15 Perbandingan jarak dengan kekerasan ............................................ 45 Gambar 4-16 Kekerasan rata-rata VHN ................................................................ 46 Gambar 4-17 Perbandingan hasil pengujian korosi .............................................. 48
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DAFTAR PERSAMAAN Persamaan 2.1 Persamaan diameter nugget minimal (d) agar terjadi patah pullout (PO) ..................................................................................................................... 6 Persamaan 2.2 Persamaan model patah intefacial (IF) ........................................ 6 Persamaan 2.3 Persamaan model patah pullout (PO) .......................................... 6 Persamaan 2.4 Persamaan diameter kritis ............................................................ 7 Persamaan 2.5 Persamaan beban patah pada kondisi interfacial (IF) .................. 8 Persamaan 2.6 Persamaan beban patah pada kondisi pullout (PO) ...................... 8 Persamaan 2.7 Persamaan diamter kritis .............................................................. 8 Persamaan 2.8 Persamaan kegagalan interfacial (IF) ......................................... 8 Persamaan 2.9 Persamaan kegagalan pullout (PO) .............................................. 9 Persamaan 3.4 Persamaan number equivalen .................................................... 23 Persamaan 3.5 Persamaan equivalen weight ...................................................... 23 Persamann 3.6 Persamaan laju korosi ................................................................. 23
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DAFTAR LAMPIRAN Lampiran 1 Grafik uji tarik-geser ....................................................................... 53 Lampiran 2 Grafik uji tarik-geser ....................................................................... 54 Lampiran 3 Grafik uji tarik-geser ....................................................................... 55 Lampiran 4 Grafik uji tarik-geser ....................................................................... 56 Lampiran 5 Grafik uji tarik-geser ....................................................................... 57 Lampiran 6 Grafik uji tarik-geser ....................................................................... 58 Lampiran 7 Grafik uji tarik-geser ....................................................................... 59 Lampiran 8 Grafik uji tarik-geser ....................................................................... 60 Lampiran 9 Grafik uji tarik-geser ....................................................................... 61 Lampiran 10 Grafik uji tarik-geser ..................................................................... 62 Lampiran 11 Grafik uji tarik-geser ..................................................................... 63 Lampiran 12 Grafik uji tarik-geser ..................................................................... 64 Lampiran 13 Grafik uji tarik-geser ..................................................................... 65 Lampiran 14 Grafik uji tarik-geser ..................................................................... 66 Lampiran 15 Grafik uji tarik-geser ..................................................................... 67 Lampiran 16 Grafik uji tarik-geser ..................................................................... 68 Lampiran 17 Grafik uji tarik-geser ..................................................................... 69 Lampiran 18 Grafik uji tarik-geser ..................................................................... 70 Lampiran 19 Tabel uji tarik-geser tanpa perendaman ........................................ 71 Lampiran 20 Tabel uji tarik-geser peendaman 1 bulan ...................................... 72 Lampiran 21 Tabel uji tarik-geser perendaman 2 bulan .................................... 73 Lampiran 22 Tabel uji tarik-geser ...................................................................... 74 Lampiran 23 Hasil pengujian mikro vikers ........................................................ 75 Lampiran 24 Hasil pengujian korosi .................................................................. 76 Lampiran 25 Hasil pengujian korosi .................................................................. 77 Lampiran 26 Hasil pengujian korosi .................................................................. 78 Lampiran 27 Hasil pengujian korosi .................................................................. 79
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