EFFECT OF CURRENT -WELDING ON THE CORROSION BEHAVIOR OF LOW CARBON STEEL (1020) TIG WELDING JOINTS IN 3.5% NACL

Abstract

Welding is one of important industrial processes, therefore many techniques are development to get an efficient and low cost welding for different kinds of materials. In this research, the corrosion behaviors studied of many welded joints which were implemented using (TIG Welding) method on Low carbon steel 1020 AISI at constant voltage, welding speed and variable DC current for each pass. Microstructure of weld zones, according to standard ASTM (G71-31) a number of corrosion examination samples are equipped with the measurements of (15 x 15 x3) mm which distributed into the many groups. Corrosion test was done by electrochemical methods for all specimens in environments of 3.5% NaCl solution. Corrosion rate is calculated using the Tafel equation. The results which obtained shows increase in corrosion rate of the weld joint which made at four passé with decreasing DC current for each pass compared with other weld joints and base metal but the increasing in DC current of the weld joint which carried out at three passes improved the corrosion rate compared with weld joint also carried out at three pass but include decrease in DC current.