Pengaruh pre-strain dan tegangan listrik terhadap sifat fisik mekanik dan korosi sambungan las titik (RSW) logam beda jenis antara AISI 430 dan JSL AUS (J1)

Abstract

Distortion often occurs in thin plate welding process. Pre-strain is ussualy choosen for repairing those failure. Pre-strain is the method which stretchs and holds the material before welding process. The main objective of this research is to investigate the effect of pre-strain and voltage on corrosion, physic and mechanics properties of dissimilar metals spot welded between AISI 430 and J1. Variation of pre-strain treatment is (0%; 0.2%; 0.5%; 1%) and voltage is (1.60V; 1.79V; 2.02V; 2.30V). Electrode pressure force is 500N. NaCl 3.5% solution is used for potentiodynamic polarization corrosion test. As a result of the experiment showed that nugget size enlarge with increasing voltage which cause pullout failure mode. Nugget size decrease after pre-strain was applied to the specimen and makes interfacial failure mode. Variation of pre-strain at 1% and voltage at 2.30V had the highest corrosion rate of 0.0497 mm/y. Pitting corrosion is the corrosion which occurs in the specimen. Pitting corrosion occurs due to overheating when welding with pre-strain treatment cause the protective oxide passive film layer from AISI 430 was damaged.