1. Factors influencing the rate of corrosion
Corrosion and Potable Water Quality of Majmaah Region, North Riyadh – KSA Research Centre: Engineering and Applied Sciences Shemy M. Ahmed, Sameh S. Ahmed, Ehab A. Abdelhafiz, Hassan I. Mohamed (1) Mechanical Engineering Department – College of Engineering (2) Civil Engineering Department – College of Engineering
Kingdom of Saudi Arabia
Ministry of Higher Education
Majma’ah University
1432/2011
Pitting
Project Objective
Localized pitting corrosion has been recognized as a source of water system equipment failure
The aim of the present work is to investigate the effect of different tap water resources in North Riyadh on the Localized pitting corrosion morphology of carbon steel.
Cast iron pipe without any protection from pipe corrosion (pipe burst, poor water quality customer compliant)
Corrosion: The destruction or the deterioration of a material that occurs due to reaction with its environment.
Types of Corrosion
Impact of corrosion:
Costly system repairs and replacements
Disruption of service
Structural and environmental damage
Reduced water quality
Improper treatment
Discolored water (red, brown or blue),
Decreased system capacity
Uniform
Pitting
Stress corrosion
Corrosion Fatigue
Dissimilar metal
Concentration cells
Crevice
Stray current
Dezincification
Graphitization
Impingement attack
Cavitations
Factors influencing the rate of corrosion
Schematic layer structure in aged unprotected cast iron and steel pipes ( Bohlar et al, 2005)
Bimetallic couples
Stressed areas
Conductivity
Aeration
Ion concentrations pH
Temperature
Flow rate and turbulence
Anaerobic bacteria
2nd Phase:
Experimental Work
Immersion test
Test material
Collective of water analysis
Test times, 3, 5, 7, 9 hours
3rd Phase:
Results
Microscopic observation
Data analysis
Macrograph pictures of corrosion products formed in aged pipe internal surfaces which were established over decades in the actual TBW pipe distribution systems receiving conventional Groundwater (G1) treated by aeration, disinfection, and pH stabilization:(a) Unlined cast iron, (b) Galvanized steel © Lined iron (d) PVC.
4th Phase:
Report writing
Macrographs of the failed tube samples (a) outer surface and (b) Inner surface