Investigation on the current flow effect on AISI 321 stainless steel welded part corrosion behavior

In the present study، the microstructure and corrosion resistance of AISI 321 austenitic stainless steel، which is widely employed in the oil and gas industries due to high corrosion resistance، with GTAW process by welding with various constant current and pulsed current were investigated. Polarization tests were performed in NACL 3. 5% in order to analyze the corrosion behavior of base metal and welded test coupons and compare their corrosion resistance. Micro structural studies by metallographic of samples with optical microscope (OM) and scanning electron microscope (SEM) and polarization test results revealed that using PCGTAW (Pulsed current gas tungsten arc welding) reduce heat input up to 50%، dendrite branches break down and reduced heat inputs and HAZ width and increase corrosion resistance of weld metal that`s similar to base metal corrosion resistance.