EFFECT OF CONSENTRATION, SURFACE ROUGHNES, AND WELDED AREA ON THE CORROSION RATE OF STAINLESS STEEL 316L IN SULFURIC ACID ENVIRONMENT

• Main Author: Cahyaningtyas, Oktarina
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72902
• Institution: Institut Teknologi Bandung

Corrosion is a phenomenon that is avoided in the oil industry due to its serious impact on production. The selection of appropriate materials is one of the solutions to reduce repair costs. Sulfuric acid is one of the inevitable factors causing corrosion as it is used as a chemical for the production process of high-octane fuels. Testing was conducted using immersion methods on welded and bent specimens, with variations in surface roughness and solution purity. The test results showed pitting corrosion as the type of attack that occurred, and the corrosion rate tended to increase with increasing concentration until reaching a critical point. The rougher the surface, the higher the corrosion rate. Corrosion occurred at the austenite/ferrite phase boundary in both the weld metal and the base metal. Chromium sulfate formed as a corrosion product that provided protection. The oxidation reaction of the 30%wt and 40%wt immersion specimens occurred spontaneously, while the 50%wt immersion specimen required an external supply of electrons or a potential difference. Tafel curves can be used to determine the material's tendency to undergo reduction potential. The corrosion rate of the ground specimen in the 30%wt immersion was 15,34 mm/year, the 40%wt immersion was 23,035 mm/year, and the 50%wt immersion tended not to corrode due to the stability of chromium sulfate compounds and ionic conductivity.