Virtual corrosion testing on stainless steel AISI 304 welded pipe with Hydroxyethyl Cellulose in 3.5% NaCl solution and turbulent flow

Abstract

A virtual corrosion testing machine is used to investigate the corrosion inhibition efficiency and mechanism of an inhibitor in stainless-steel 304 pipes under turbulent flow conditions. The pipes are welded by the gas tungsten arc welding method and evaluated in 3.5 percent sodium chloride solution with absence (0 ppm) and presence 100, 300, and 600 ppm hydroxyethyl cellulose concentrations. The solutions are absence and presence the inhibitor, are fed in the welded pipe at a flow rate of 7,500 and 15,000 cm ^3 per minute as behaves to be turbulent flows. Electrochemical impedance spectroscopy and potentiodynamic polarization techniques are used to investigate the corrosion inhibition process. The inhibitor can adsorp on the surface of stainless steel welded pipe and inhibit the corrosion rate of the stainless steel. The concentration volumes of the inhibitor are correlating the corrosion rate in the same direction. The turbulent flow is to reduce the adsorption mechanism of the inhibitor, affect to corrosion reaction for the stainless-steel welded pipe and relate to the corrosion rate. If the flow rate increases, the corrosion rate would also increase. The corrosion inhibition efficiency is reached up to 66% by addition HEC 600ppm concentration in the condition. Pitting corrosion is observed on the heat-affected zone of the welded pipe by scanning electron microscope.

Keywords

• corrosion
• inhibitor
• pipe
• turbulent flow
• stainless steel
• electrochemical technique