TORSI

Abstrak
ABSTRAK
Teknik pengelasan friction stir welding (FSW) banyak digunakan pada proses pengelasan berbahan dasar Aluminium. Tool geometry merupakan parameter yang sangat penting dalam pengelasan FSW. Diameter shoulder merupakan salah satu parameter tool tersebut. Tujuan penelitian ini untuk mengetahui pengaruh perbedaan diameter shoulder terhadap sifat mekanis pada FSW Aluminium 5083. Parameter pengelasan yang digunakan adalah rotation speed 1600 Rpm, welding speed 24 mm/min, shoulder depth plunge 0,2 mm dan bentuk pin segilima (phentagonal). Pengelasan dilakukan dengan menggunakan variasi diameter shoulder 16 mm, 18 mm dan 20 mm. Untuk mengetahui kekuatan mekanik lasan dilakukan pengujian tarik dan untuk melihat morfologi patahan dilakukan foto makro. Kekuatan mekanis terbaik didapat dengan menggunakan shoulder diameter 18 mm. Pengelasan dengan diameter shoulder 18 mm didapat nilai ultimate tensile strength sebesar 96,45Mpa. Hasil foto makrostruktur menunjukan terdapat cacat whormhole sepanjang daerah lasan pada tiap variasi shoulder. Cacat terbesar dihasilkan dari penggunaan shoulder dengan diameter 20 mm. Nilai UTS hasil lasan lebih kecil 67,63% dibandingkan dengan base material Aluminium 5083.

Kata Kunci: Aluminium 5083, Friction Stir Welding, Tool geometry, Shoulder diameter

ABSTRACT
Friction stir welding (FSW) is a relatively new solid-state joining process. Friction stir welding (FSW) is a widely used for soft materials such as Aluminum alloys because it avoids many of the common problems of fusion welding. Tool geometry is a very important parameter in welding FSW. Shoulder diameter is one of the tool parameters. The purpose of this study is to determine the effect of differences in shoulder diameter on the mechanical properties of the FSW aluminum 5083. Welding parameters which is used are 1600 rpm rotation speed, 24 mm / min of welding speed, 0.2 mm shoulder plunge depth and pin pentagon shape. Variation of shoulder diameter is used to know the effect to the mechanical properties. Moreover, tensile testing is used to determine the mechanical strength of welds performed. However, the surface morphology of materials is analyzed by macro photo-ghraphy. The highest mechanical strength is obtained by using the 18 mm shoulder diameter. The Ultimate tensile strength of 18 mm shoulder diameter is 96.45 MPa. The surface morphology of welded materials indicates are whorm hole defects occur for all of welded materials. The biggest defect is resulting from 20 mm of shoulder diameter. The UTS of welded material is 67.63% smaller compared to the base material aluminum 5083.

Key words: Aluminum 5083, Friction Stir Welding, Tool geometry, Shoulder diameter