Analisis Sifat Fisis dan Sifat Mekanis Sambungan Las Busur Rendam Baja Paduan Rendah HSLA dengan Variasi Basicity Index Fluks.

This research investigates the mechanical and phisical properties of submerged arc steel weld metals with various flux basicity index. The welding process was performed on the flat position with 450 amperes in current, 30 Volts in voltage, and 4 mm/s in travelling speed. The filler used was EM 12K, 0 3.2 mm. A series of submerged arc welds were made on 22 mm thick HSLA (High Strength Low Alloys) steel with three differents fluxes were deposited namely 0,75 (acid), 1,60 (semi basic), and 3,40 (basic). Results show that the tensile strength of weld metals is about 1,5 times higher than the tensile strength of raw materials. Weld metals with flux BI=1,60 have highest tensile strength. Hardness of weld metals with the basicity index 0,751,60and 3,40 are 180,17, 212,69, and 190,10 VHN respectively. The oxigen contents of inclusion on the weld metals with flux BI = 0,75 is highest. Keywords : Submerged arc welding, basicity index, tensile strength, hardnes