corrosion

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corrosion

  1. 1. “ A Simple view on a complex matter”
  2. 2. • Virtually no practical and engineering material is stable. The rate of decay varies depending upon the material and its environment. • The human system cannot endure – Temp above 50 C or below 20 C – Pressures above or below our atmospheres – Presence of harmful gases such as CO, H2S, and H2. • Thus, analogous to human system, engineering materials also require protection like – coatings, inhibitors, alloy addition, design procedures, maintenance, inspection and re- furnishing.
  3. 3. Corrosion is the disintegration of an engineered material into its constituent atom due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as O2.
  4. 4. EFFECTS OF CORROSION • Reduces Strength • Life time is reduced • Metallic properties are lost • Wastage of metal
  5. 5. IMPORTANCE OF CORROSION DATA  5 mpy Good corrosion resistant material  5 to 50 mpy Low corrosion resistant material  50 mpy Unsuitable as constructional material
  6. 6. EXAMPLES OF CORROSION
  7. 7. CHEMICAL EQUATION OF CORROSION
  8. 8. Corrosion in teeth fillings
  9. 9. TYPES OF CORROSION
  10. 10. UNIFORM CORROSION  CAN BE A GOOD OR A BAD THING.  CORROSION OCCURS EVENLY OVER THE SURFACE.  OXIDE LAYER CAN BE VERY TOUGH – MAGNETITE.  FE3O4
  11. 11. GALVANIC CORROSION o CHEMICAL REACTIONS. o ELECTRONS REMOVED FROM ONE REACTANT TRAVEL THROUGH AN EXTERNAL CIRCUIT. oMETERIAL TENDS TO DISAPPEAR.
  12. 12. Microbiological corrosion Galvanic corrosion
  13. 13. Crevice Corrosion
  14. 14. PITTING CORROSION
  15. 15. STRESS CORROSION BRITTLE CRACKS FORM AT THE SITES OF STRESS. FAILURE CAN BE FAST. FAILURE CAN OCCUR AT STRESS LOADS FAR BELOW YIELD STRENGTH. THREE CONDITIONS REQUIRED FOR MOST COMMON KIND ARE ----- METAL UNDER TENSILE STRESS DISSOLVED OXYGEN CHLORIDE ION
  16. 16. ERROSION CORROSION • FLOW REMOVES PROTECTIVE LAYER. • NEW POTECTIVE LAYER FORMS USING UP METAL.
  17. 17. MICROBIAL CORROSION SIMILAR TO PITTING CORROSION. BACTERIA IN WATER.
  18. 18. Economic Impact of Corrosion Annual estimated direct cost of corrosion in the U.S. was approximately $276 billion (approximately 3.2% of the US GDP. Rust was the reason for the failure of Mianus river bridge in 1983 and Silver Bridge disaster of West Virginia in 1967
  19. 19. PREVENTIONS OF CORROSION
  20. 20. ACIVE CORROSION PROTECTION • The aim of active corrosion protection is to influence the reactions which proceed during corrosion, it being possible to control not only the package contents and the corrosive agent but also the reaction itself in such a manner that corrosion is avoided. .• Examples of such an approach are the development of corrosion-resistant alloys.
  21. 21. PERMANENT CORROSION PROTECTION • The purpose of permanent corrosion protection methods is mainly to provide protection at the place of use. The stresses presented by climatic, biotic & chemical factors are relatively slight in this situation. • For example, in factories shed are protected from extreme variations in temperature, which is frequently the cause of condensation.
  22. 22. What are the remedies or protective measures • Apply coatings on the metal surface • Removal of oxygen • Control of pH • Inhibitors • Change of potential But knowing beforehand the possible effect of corrosion led to the development of different softwares and models for corrosion rate prediction
  23. 23. Various available softwares Softwares have been developed by various organizations but few of the well known software builders are :-  OHIO UNIVERSITY  ELECTRONIC CORROSION ENGINEERS  HONEYWELL Multicorp and Freecorp are the products of Ohio University Honeywell has developed PREDICT-6.0 and PREDICTPIPE- 3.0 Two corrosion models have been developed by ELECTRONIC CORROSION ENGINEERS and NORSOK
  24. 24. Multicorp v4.2
  25. 25.  Effect of multiphase flow (two- and three-phase flow)  Effect of temperature (1-100 C)  Effect of CO2 partial pressure (0 – 2 MPa)  Effect of H2S content (0 – 1 MPa)  Effect of organic acids (0 – 10,000 ppm)  Effect of pH and brine chemistry (pH3 – pH7)  Effect of steel type  Effect of inhibition by crude oil and/or corrosion inhibitors  Magnitude and morphology of localized attack
  26. 26. Processing window where the development of the corrosion rate and surface scales can be tracked as a function of time
  27. 27. Batch run results
  28. 28. Line run results
  29. 29. Norsok m-506 This model calculates the CO2 corrosion rate on the basis of given temperature, pH , CO2 partial pressure and shear stress
  30. 30. Electronic Corrosion Engineers • It consists of a tubing project and a pipeline project
  31. 31. Created & Edited by – ABHIJEET DASH
  32. 32. REFERENCES • http://www.corrosioncenter.ohiou.edu/software/multicor p/ • https://www.honeywellprocess.com/en- US/explore/products/advanced-applications/asset- management/corrosion-prediction-and- assessment/Pages/predict-6.0.aspx • https://www.honeywellprocess.com/en- US/explore/products/advanced-applications/asset- management/corrosion-prediction-and- assessment/Pages/predictpipe-3-0.aspx • http://www.corrosionhelp.com/services.htm#Electroche mical Analysis • http://www.corrosionservice.com/

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