Abstract:
3 l 6L stainless steel is one of the most consumable materials in pipe, flange, valve and
others. ft is an alloy which was produced to encounter the weaknesses of their basic
element such as hardness, strength, corrosion resistant and other properties in certain
aggressive condition such as seawater and petroleum environment. In this study, 316L
stainless steel was used to study the effect of the cooling method of tungsten inert gas
(TIG) welding in causing the corrosion in solution. There are two different cooling
methods for each type of metals where the samples were cooled in a room temperature or
air cooling while another samples facing the rapid cooling process called quenching.
3 l 6L stainless steel had divided into 3 partitions which is heat affected zone (HAZ), weld
metal and base metal. The corrosion behavior and microstructure of weld metal, HAZ,
base metal and as-weld (coupled weld and base) were compared together. Microstructure
was investigated using scanning electronic microscopy (SEM) through image of grain
boundaries on metal. Tungsten inert gas was used to weld the samples. The samples were
exposed to the highly corrosive environment in salt spray chamber at 37°C which provide
very similar environment as the real marine environment. After being in the chamber for
several periods, the samples weight loss analysis was done. The samples continued with
test of electrochemical impedance spectroscopy using the frequency response analyzer
(FRA) and general purposes electrochemical system (GPES) module. Weight loss
anaJysis done before and after the samples being put in the salt spray chamber to
determine their changes after several periods. Based on the result, it was determined that
corrosion rate of quenching samples more than air cooling samples because of HAZ
increased anodic element. So, quenching method as post weld heat treatment (PWHT)
increased the corrosion rate of as-weld samples. HAZ samples have less corrosion
resistance th
