ANALISIS PENGARUH VARIASI LASER POWER DAN WOBBLE FREQUENCY PROSES LASER WELDING PADA MATERIAL SUS 304 TERHADAP STRUKTUR MIKRO DAN NILAI KEKERASAN

Abstract

Welding is a major process in fabrication industry of transportation. So, that required efficiency and good welding results. This study used laser welding process with 1 mm thickness austenistic SUS 304 material. Crucial parameters in laser welding are power and wobble frequency, because they can affect material’s mechanical properties. This research was conducted to determine the effect of varying power and wobble frequency values ??of SUS 304 material on the microstructure and hardness values. The power used was 33% and 38% varied with wobble frequencies 10 Hz and 12 Hz. The specimen testing are visual inspection, macro structure test, micro structure test, SEM, and hardness test. The results of macro structure test show that the greater power and wobble frequency values, the deeper penetration. Micro-test results on the material show that the formation of lathy ferrite occurs in areas with a high cooling rate, while skeletal ferrite is formed in areas with a low cooling rate. The highest hardness value in weld metal area is at variation 38% power and 12 Hz wobble frequency, which is 197.23 HV. SEM testing showed no micro size defects and finer grain structures. It shows that the greater the value of power and wobble frequency, the deformation occurs and the results of the welding are increasingly concave.