The effect of corrosion inhibitors on stainless steel pipes welded by gas tungsten arc welding in 35 percent sodium chloride solution under the flow conditions

Name: Parinya Boonsa

LCSH: Kasetsart University -- Dissertations. Ph.D. (Materials Engineering) 2020

Classification :.LCCS: TA467

LCSH: Kasetsart University. -- Department of Materials Engineering -- Dissertations

LCSH: Tribo-corrosion

LCSH: Pipe, Steel -- Welding

LCSH: Electric welding

LCSH: Gas tungsten arc welding

Abstract: The aim of this study is to investigate the corrosion rate and inhibition mechanism of inhibitors in stainless-steel grade 304 pipe. The pipes are welded by gas tungsten arc welding (GTAW) method and evaluated in 3.5 percent sodium chloride solution with and without Hydroxyethyl cellulose (HEC), Hexa-ammonium heptamolybdate tetrahydrate (H-AHT), or H-AHT mixed with HEC at 100ppm, 300ppm and 600ppm concentrations. The solution with and without inhibitors are fed in the welded pipe at flow rate of 7.5 liters per minute and 15 liters per minute. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques are used to investigate the corrosion inhibition process. HEC can adsorption on the pipe’s surface and inhibition the corrosion rate of the stainless steel. HEC’s concentration volumes are correlating the corrosion rate in the same direction as H-AHT cannot precipitate as oxides on the surface of the pipe due to turbulence flowing in the pipe. Moreover, the H-AHT also enhances the corrosion to have a higher corrosion rate than without inhibitor. The corrosion rate of mixed inhibitor between HEC and H-AHT is more than without inhibitor but less than H-AHT. Due to HEC can adsorb on the surface of the stainless steel pipe to reduce oxidation. Including the molecular structure of H-AHT is more molecular weight than HEC, so H-AHT inhibitor is affecting to corrosion more than HEC. The flowing rate of 7.5 and 15 liters per minute behaves of turbulence flow which may reduce adsorption mechanism of the inhibitor and affect to corrosion reaction for the stainless-steel pipe. Fluid flow rate is relating to corrosion rate if the flow rate increases, the corrosion rate would also increase.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Aphichart Rodchanarowan

Role: Thesis Advisor

Created: 2020

Modified: 2025-06-30

Issued: 2025-06-30

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2563/parinya-boo-all.pdf

CallNumber: TA467 .P37

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Materials Engineering

Grantor: Kasetsart University

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