PENGARUH PREHEAT TERHADAP LAJU PERAMBATAN RETAK FATIK SAMBUNGAN LAS TIG PADA PENGELASAN ALUMINIUM PADUAN 6061-T6

• Main Authors: , Sirama, SST, , Mochammad Noer Ilman, S.T., M.Sc., Ph.D.
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2011
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/90499/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=53534
• Institution: Universitas Gadjah Mada

Al 6061-T6 is widely used in structures and machinery such as rail way, cars bodies, automotive, ships, dump trucks and trailers because it has good mechanical properties, but these metals relatively have low weldability properties and weld joints are susceptible to failure due to the forces on the structure. One of the methods to improve the fatigue resistance is to reduce the residual stress through preheat treatment before and during welding. This study aims to determine the effect on the quality of welding preheat temperatures are shown by test micro-structure, the static properties (hardness and tensile strength), and dynamic properties (fatigue crack propagation rate) at the junction of Al 6061-T6 welded with TIG welding. The joint process of plates of Al 6061-T6 size 3x100x300 (mm) using TIG welding parameters, welding wire diameter of 2.4 mm (EWP), the electrical current (I) 130 Ampere with AC polarity, resistance (E) 14,0 volts, gas flow 10 liters/minute, the welding speed (v) 0.20 m/min and heat input (Qw) 0,055 kJ/mm. Results show that changes in the microstructure of the weld metal is characterized by enlargement of dendrites, the HAZ and parent metal region occur due to the influence of grain enlargement and heat treatment weld preheat. Both weld metal hardness without preheat and preheat relatively the same with 64 VHN, while the hardness in the HAZRough region increased to 80 VHN and HAZSmooth area decreased to 65 VHN, but in the area of the parent metals violence in preheat 100ºC, 150ºC and 200ºC decreased their respectively by 4.9%