New processincreasecorrresist 11-11-09

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New processincreasecorrresist 11-11-09

  1. 1. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 New Processes to Increase Corrosion Resistance on Stainless Steel Siegfried Piesslinger-Schweiger; POLIGRAT GmbH
  2. 2. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Content <ul><li>New Processes to improve the Corrosion Resistance on Stainless Steel </li></ul><ul><ul><li>Basics </li></ul></ul><ul><ul><li>Processes </li></ul></ul><ul><ul><li>Applications </li></ul></ul>
  3. 3. <ul><li>is determined by the </li></ul><ul><li>1. Alloy and Structure of the Base Metal </li></ul><ul><li>2. Passive Layer </li></ul><ul><li>3. Environment </li></ul><ul><li>Interacting with Oxygen from environment the Chrome of the Base Metal </li></ul><ul><li>forms the Passive Layer consisting of Chrom Oxides, which densely </li></ul><ul><li>covers and protects the surface of the Base Metal. </li></ul><ul><li>Consequence: </li></ul><ul><li>As long as Stainless Steel does not corrode, only the Passive Layer gets </li></ul><ul><li>into contact with the environment. The properties of the Passive Layer determine the behavior of the Stainless Steel surface. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 The Corrosion Resistance of Stainless Steel
  4. 4. <ul><li>The Base Metal </li></ul><ul><li>Alloy and Structure provide the basic conditions for the formation of the Passive Layer. They influence the corrosion resistance indirectly. </li></ul><ul><li>The Passive Layer </li></ul><ul><li>Chemistry, Structure and electrical properties of the Passive Layer formed on the surface of Stainless Steel by Alloy and Crystalline Structure directly influence the corrosion resistance. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 The System providing Corrosion Resistance
  5. 5. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Well known Facts Concerning the Passive Layer <ul><li>The Passive Layer is a non-metallic, oxidic and crystalline layer of about 10 nm thickness. </li></ul><ul><li>The Passive Layer contains Chrome Oxide and Iron Oxide in a Cr/Fe ratio of 1:2 – 2:1 depending on the surface condition. </li></ul><ul><li>The Passive Layer is a semiconductor, which is conducting electrons and insulating metal ions. </li></ul>
  6. 6. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Additional Facts Concerning the Passive Layer <ul><li>The Iron in the Passive Layer is not firmly fixed to oxides. It can be set free and is able to migrate within the Passive Layer. </li></ul><ul><li>The Iron in the Passive Layer plays an active role in the corrosion mechanism of Stainless Steel. </li></ul><ul><li>The crystalline structure of the Passive Layer influences the corrosion mechanism. </li></ul><ul><li>The Passive Layer also contains metallic Chrome and Iron besides the oxides. </li></ul>
  7. 7. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Influence of Iron (POLINOX-Protect) <ul><li>A new method (POLINOX-Protect) allows the extraction of most (> 85%) of the Iron from the existing Passive Layer without removing it. </li></ul><ul><li>The extraction of Free Iron from the whole Passive Layer down to the Base Metal produces a Cr/Fe-ratio in the range of 6:1 to 8:1 depending on temperature and duration of application. </li></ul><ul><li>The resulting effect shows a significant increase of the pitting corrosion potential as well as of the rest corrosion potential. </li></ul><ul><li>The resistance to temperature discoloration (thermic oxidation) increases for about 150°C. </li></ul><ul><li>The incubation time for stress corrosion cracking increases at least for the factor 2. </li></ul>
  8. 8. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Chrome-Iron Ratio on S.S. AISI 316 Depending on Treatment untreated HNO3 Protect AISI 316 cold rolled AISI 316 electropolished AISI 316 ground grain 240 Cr/Fe ratio
  9. 9. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Chrome-Iron Ratio through the Passive Layer Cr/Fe ratio untreated with POLINOX-Protect Passive Layer Base Metal Layer thickness in nm
  10. 10. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential on AISI 304 Treated with POLINOX-Protect at Different Temperatures and Different Periods of Time
  11. 11. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential of S.S. AISI 304 according to Surface Finish AISI 304 cold rolled AISI 304 electropolished AISI 304 ground grain 240 pitting corrosion potential AISI 304 POLINOX-Protect untreated
  12. 12. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Open Circuit Potential of S.S. AISI 316 with and without Passivation with POLINOX-Protect AISI 316 cold rolled AISI 316 electropolished AISI 316 ground grain 240 open circuit potential AISI 316 POLINOX-Protect untreated
  13. 13. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Corroded S.S. AISI 316 before and after Cleaning with POLINOX-Protect Applied on Site by Wiping and Staying on for 3 Hours at 20 °C
  14. 14. <ul><li>Scale and discolorations in the area of welding seams and heat affected zones consist of metal oxides in the ratio close to the alloy. </li></ul><ul><li>POLINOX-Protect selectively cracks the Iron Oxides (except hematite) and removes the Iron preserving the oxide layer. </li></ul><ul><li>After removal of Iron the Oxide Layer preferently is formed by Chrome Oxide and shows a comparable high corrosion resistance as the not heat-affected and passivated areas. </li></ul><ul><li>Consequently, treatment with POLINOX-Protect may partially replace pickling. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Descaling of Welding Seams by POLINOX-Protect
  15. 15. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 S.S. AISI 304 with Welding Seam Partially Treated with POLINOX-Protect at 50 °C for 3 Hours
  16. 16. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 S.S. AISI 316 Ti with Welding Seam before and after Treatment with POLINOX-Protect at 70 °C for 3 Hours
  17. 17. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Comparison of Pitting Corrosion Potential at Base Metal, Heat Affect Zone and Welding Seam on AISI 316Ti, 20.000 ppm Chloride
  18. 18. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Influence of Crystalline Structure (POLINOX-Protect TC) <ul><li>Based on the idea, that the migration of Ions would mostly happen along crystal borders, POLIGRAT applied heat treatment to produce changes within the Passive Layer. </li></ul><ul><li>The treatment was performed on different Alloys using different temperatures below the level of thermic discoloration and for different times of application. </li></ul><ul><li>The resulting effects show a significant increase in corrosion potentials specifically after Iron extraction by POLINOX-Protect. Depending on structure (ferritic or austenitic) an individual optimum exists in view of temperature and time of treatment. </li></ul>
  19. 19. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential of S.S. AISI 304 (Austenitic) Treated with POLINOX-Protect TC at Different Temperatures
  20. 20. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential of S.S. AISI 304 (Austenitic) Treated with POLINOX-Protect TC at 200 °C Depending on Time for Heat Treatment
  21. 21. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential of S.S. AISI 430 (Ferritic) Treated with POLINOX-Protect TC at Different Temperatures
  22. 22. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential of S.S. AISI 430 (Ferritic) Treated with POLINOX-Protect TC at 140 °C Depending on Time for Heat Treatment
  23. 23. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Pitting Corrosion Potential on S.S. – Surface Polished with Grain 240 untreated HNO3 POLINOX-Protect AISI 430 AISI 304 AISI 316 Ti AISI Alloy 59 POLINOX-Protect TC
  24. 24. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Stress Corrosion Cracking on AISI 321 (hours) untreated Protect TC
  25. 25. <ul><li>POLINOX-Protect TC combines the application of POLINOX-Protect with a following controlled heat treatment. </li></ul><ul><li>POLINOX-Protect TC significantly increases the corrosion resistance. </li></ul><ul><li>The optimum temperature is in the range of 140 °C (for ferritic S.S.) and 220 °C (for austenitic S.S). </li></ul><ul><li>The optimum time for heat treatment is about 5 to 15 minutes for ferritic Stainless Steel and up to 60 minutes for austenitic Stainless Steel. </li></ul><ul><li>The heat treatment can also be realized at a later date. </li></ul><ul><li>The effect is not reversible. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 POLINOX-Protect TC
  26. 26. <ul><li>POLINOX-Protect is applied as dipping process, spray-on paste or brush paste for a period of 4 – 5 hours at temperatures from 20 °C to 70 °C. Following, the surfaces are cleaned with water. </li></ul><ul><li>POLINOX-Protect is based on a special combination of organic complexing and chelating agents. It is fully organic, biodegradable, not hazardous, not fuming or smelling and is not enriched with heavy metals during application. </li></ul><ul><li>POLINOX-Protect can be applied without restriction to all grades of Stainless Steel with a chromium content higher than 15 % on new parts and for maintenance. Alloys with a lower chromium content can be treated after definition of parameters by prior sample test. </li></ul><ul><li>POLINOX-Protect can be used for cleaning and corrosion protection by the same treatment. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 POLINOX-Protect – Properties and Application
  27. 27. <ul><li>Improving the resistance to pitting corrosion, ferrite induced corrosion and stress corrosion cracking (corrosion protection). </li></ul><ul><li>Increasing the resistance to thermal discoloration. </li></ul><ul><li>Removal of ferritic contamination, rust and corrosion products and restoration of corrosion resistance on a higher level (refurbishment). </li></ul><ul><li>Restoring the corrosion resistance of welding seems and heat affected zones. </li></ul><ul><li>Reduction of rouging. </li></ul><ul><li>Preserving the surface finish unchanged. </li></ul><ul><li>Locally damaged surfaces repassivate at the same level of corrosion resistance. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Effects of POLINOX-Protect on Stainless Steel
  28. 28. <ul><li>The new Passivation Process is in field application for about five years </li></ul><ul><li>comprising a wide range of parts: </li></ul><ul><li>Automotive body parts </li></ul><ul><li>Architecture </li></ul><ul><li>Food processing machines </li></ul><ul><li>Street furniture </li></ul><ul><li>Fasteners and springs </li></ul><ul><li>Pharmaceutical and chemical processing plants </li></ul><ul><li>Swimming pools </li></ul><ul><li>The new process is applied on new parts as well as on used parts for </li></ul><ul><li>repair and reconditioning. </li></ul>Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Practical Experience
  29. 29. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Case Histories <ul><li>Hand rails made of S.S. tube, material AISI 304, polished grain 240, placed along the Atlantic seashore stained and corroded heavily and had to be cleaned every 4 - 6 weeks. After cleaning with POLINOX-Protect for more than 1 year no corrosion has reappeared. </li></ul><ul><li>Body parts of cars including front and bonnet made of S.S. 304 with brushed surface are passivated by POLINOX-Protect. During production for a period of three years no corrosion appeared despite exposure to deicing salts. </li></ul>
  30. 30. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Rolls Royce Hood made from Stainless Steel 304 Passivated by POLINOX-Protect
  31. 31. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Case Histories <ul><li>Fishing hooks made of Stainless Steel 430 showed insufficient corrosion resistance to sea water even after electropolishing (salt spray less than 25 hours). POLINOX-Protect TC (dipping for 3 hours at 60 °C and heating to 140 °C for 5 minutes) improved the corrosion resistance to > 500 hours. </li></ul>
  32. 32. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 POLINOX-Protect TC Fishing Hooks
  33. 33. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Conclusions <ul><li>There is a new approach to corrosion resistance of S.S. by considering S.S. as a „composite“ consisting of a metallic base and a non-metallic protective layer, the Passiv Layer. </li></ul><ul><li>Research on the influence of chemistry and structure of the Passive Layer to the corrosion resistance of S.S. has revealed a surprisingly complex and variable system. </li></ul><ul><li>The corrosion resistance of S.S. can be significantly improved by upgrading the Passive Layer independently from the base metal. </li></ul>
  34. 34. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Conclusions <ul><li>A special Passivation Process has been developed to improve chemistry and structure of the Passive Layer. It provides substantial improvements in a wide range of corrosion effects. </li></ul><ul><li>The Passivation Process is save, easy and proven in application. It is not hazardous, biodegradable, and easy to apply. </li></ul><ul><li>The R&D work is not finished yet. There is still a lot to do!! </li></ul>
  35. 35. Siegfried Pießlinger-Schweiger Stainless Steel Congress, Maastricht, November 11th, 2009 page of 35 Thank You for Listening

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