Galvanize_It_10_20_08.ppt
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This document provides information about a seminar hosted by the American Galvanizers Association (AGA) on hot-dip galvanized steel. The seminar aims to educate architects, engineers, and specifiers about using hot-dip galvanized steel to address corrosion issues. It covers topics like the corrosion problem in North America, how galvanized steel provides barrier and cathodic protection against corrosion, the hot-dip galvanizing process, common galvanized coating specifications, and how galvanized steel can lower life-cycle costs compared to painted steel.
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Galvanize_It_10_20_08.ppt
- 1. Galvanize It! Seminar American Galvanizing Association
- 2. 2 American Galvanizers Association The American Galvanizers Association (AGA) is a non-profit trade association dedicated to serving the needs of after-fabrication galvanizers, fabricators, architects, specifiers, and engineers The AGA provides technical support on today's innovative applications and state-of-the-art technological developments in hot-dip galvanizing for corrosion control
- 3. 3 American Institute of Architects Learning Units (HSW) Continuing Education Credit National Council of Examiners for Engineering & Surveying Professional Development Hours
- 4. 4 Continuing Education AIA/CES Policy on Endorsement: The following program is registered with the AIA/CES and does not include content that may be deemed or construed to be an approval, sponsorship, or endorsement of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
- 5. 5 Continuing Education The American Galvanizers Association has met the standards and requirements of the Registered Continuing Education Providers Program. Credit earned upon completion of this program will be reported to RCEPP. A certificate of completion will be issued to each participant. As such, it does not include content that may be deemed or construed to be an approval or endorsement by NCEES or RCEPP.
- 6. 6 Purpose of this Seminar The purpose of this seminar is to inform and educate architects, engineers, and other specifiers about hot-dip galvanized steel and how it can address the growing corrosion problem throughout North America.
- 7. 7 Learning Objectives At the end of this presentation you will be able to: • Recognize the corrosion issues confronting the United States • Describe how zinc coatings, specifically hot-dip galvanizing, can protect against steel corrosion • Incorporate sound corrosion protection into the design of steel products that can significantly decrease maintenance costs over the life of a structure
- 8. Tour of the City
- 10. 10 The Corrosion Problem Bridge in Denver, CO Bridge in Denver, CO
- 11. 11 The Corrosion Problem Corroded Trolley
- 12. 12 The Corrosion Problem Coors Field – Denver, CO
- 13. 13 The Corrosion Problem Corroded Pier
- 14. 14 The Corrosion Problem Williamsburg Bridge - New York City, NY
- 15. 15 Corrosion Costs NACE, CC Technologies, & FHWA jointly produced a report in 2001 detailing the costs of corrosion • $297 billion USD annually • 3.1% of US GDP (1998) Hazardous • Public safety, property damage, environmental contamination Natural Resources • Waste production, increased energy consumption Public Outcry • Traffic, inconvenience
- 18. 18 Cathodic Protection: Galvanic Series ZINC - Anode STEEL - Cathode This arrangement of metals determines what metal will be the anode and cathode when the two are put in a electrolytic cell (arrangement dependent on salt water as electrolyte).
- 19. 19 Cathodic Protection With a cathodically protective coating, such as galvanized steel, damaged areas will be protected by the surrounding zinc Zinc Coating Bare Steel Exposed Steel is Protected
- 20. 20 HDG Process Steel is dipped in a series of tanks including solutions that remove impurities from the steel surface. The galvanizing reaction only occurs on perfectly clean steel. The steel is inspected after galvanizing to ensure conformance to the appropriate specifications.
- 21. 21 Long-Lasting Zinc Protection Barrier Cathodic Zinc Patina Zinc Patina Cathodic Barrier Long-lasting Protection
- 22. 22 HDG Process: Surface Prep Zinc-iron metallurgical bond only occurs on clean steel Degreasing • Removes dirt, oils, organic residue Pickling • Removes mill scale and oxides Fluxing • Mild cleaning, provides protective layer Caustic cleaning
- 23. 23 HDG Process: Galvanizing Steel articles are immersed in a bath of molten zinc (≈ 830 0F) > 98% pure zinc, minor elements added for coating properties (Al, Bi, Ni) Zinc reacts with iron in the steel to form galvanized coating. Zinc bath removal
- 24. 24 HDG Process: Inspection Steel articles are inspected after galvanizing to verify conformance to appropriate specs. Surface defects easily identified through visual inspection. Coating thickness verified through magnetic thickness gauge readings.
- 27. 27 Edge Protection Micrograph of galvanized edge Same thickness at corner
- 28. 28 Additional Benefits of HDG Complete Coverage
- 29. 29 Additional Benefits of HDG Variety of sizes and shapes
- 30. 30 Additional Benefits of HDG Availability
- 31. 31 Galvanizing is Green Zinc is 100% recyclable as is the steel • Properties of zinc do not degrade w/ reprocessing • Zinc is a natural element in the Earth’s crust The longevity of galvanizing means no additional energy exerted or waste created maintaining galvanized structures
- 32. 32 Estimated Service Life of HDG
- 33. Other Zinc Coatings for Corrosion Protection
- 34. 34 Metallizing Shop or in-field application Suitable for very large pieces Coating Properties: • Thick coating • Mechanical bond • Less dense than HDG zinc layers • No interior coverage Metallizing Appliation
- 35. 35 Zinc Rich Paint Metallic zinc dust • Inorganic • Organic Barrier protection Cathodic protection • Limited • Dependent on % Zn Use salt spray data to make performance claims Zinc Rich Paint Application
- 36. 36 Sheet Galvanized Produced by a continuous in-line hot-dip process • Coil-to-coil process • 400-500 FPM • “Air knives” remove excess zinc • Pure zinc with little alloy layer • Galvannealed (Zn-Fe) • Galvalume (55% Al) Sheet Steel of Continuous
- 37. 37 Sheet Galvanized ASTM A653 – specify total coating weights, most common G60 and G90 • Weights represent total coating weight for both sides of the sheet Coating Weight (ounces/sq. ft.) Coating Thickness per Side (mils) G60 0.60 0.54 G90 0.90 0.81
- 38. 38 Electroplated Strip, sheet, or small parts • Smooth finish • Slightly more expensive than sheet galvanized Good formability Paintable Electroplating Application
- 39. 39 Zinc (Mechanical) Plating Similar to electroplating • used for fasteners and small parts Parts are tumbled in drum with zinc powder and glass beads • mechanically bonded zinc Mechanical Plating Application
- 40. 40 Other Zinc Coatings Metallizing Hot-Dip Galvanized Zinc-Rich Paint Sheet Galvanized Electroplated
- 42. 42
- 43. 43 Materials Suitable for Hot-Dip Galvanizing
- 44. 44 Hot-Dip Galvanized Fasteners Hot-dip galvanized fasteners are recommended for joining HDG structurals
- 46. 46 Coating Appearance Newly Galvanized Newly Galvanized Newly Galvanized Newly Installed No Spangle Highly Spangle Dull Coating Shiny & Dull Coating
- 48. 48 Weathering of Galvanized Steel Photo taken: 12/18/02 Photo taken: 03/28/03
- 49. 49 Dissimilar Thicknesses Different thickness • Zinc bath temperature at different times Similar thickness • Maintain original shape
- 50. 50 Galvanizing Oversized Pieces Progressive Dipping
- 54. 54 ASTM Standards for Galvanizing Galvanized Products • ASTM A 123 – general • ASTM A 153 – small parts • ASTM A 767 – rebar Supporting Specifications • ASTM A 143 – embrittlement • ASTM A 384 – distortion • ASTM A 385 – high-quality coatings • ASTM A 780 – repair • ASTM D 6386 – surface prep for painting over
- 55. 55 ASTM A 123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products • Coating Thickness – material category and steel thickness • Finish – continuous, smooth, uniform • Adherence – should be tightly adherent through all expected uses of article
- 56. 56 ASTM A 153 Standard Specification for Zinc Coating (Hot- Dip) on Iron and Steel Hardware • Coating Thickness – material category, steel thickness, length • Finish – continuous, smooth, uniform • Adherence – should be tightly adherent through all expected uses of article
- 57. 57 ASTM A 767 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement • Coating Thickness – smooth or deformed (no wire), bar size • Chromating –prevent reaction between fresh cement and recently galvanized material • Bend Diameters – flaking and cracking due to fabrication are not rejectable.
- 58. 58 ASTM A 780 Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings • Zinc-rich paint, zinc-based solder, or metallizing • Zinc-rich paint - most common but must have certain amounts of zinc dust as required by spec • Zinc-based solder – good for small areas, closely mirrors typical HDG coating appearance • Metallizing – excellent corrosion protection
- 59. Hot-Dip Galvanizing Costs Less & Lasts Longer
- 60. 60 Quantitative Analysis Initial cost vs. Life- cycle cost • Based on 2006 galvanizing industry survey - nationwide • 2006 KTA-Tator paper paint industry survey – nationwide • Standard mix of steel products (structural, tubing, plate) • 10,000 ft2 project
- 61. 61 www.galvanizingcost.com Survey data organized in a database Based on specific project data input by the user, (job size & location, coating type, expected service life, etc.) The web site automatically calculates initial and life-cycle cost for the specified paint systems and hot-dip galvanizing
- 62. 62 Initial Cost Material Shop cleaning labor Shop application Field labor Pneumatic Bulk Trailers
- 63. 63 Initial Cost ($/ft2) Coating System $/ft2 Inorganic Zinc $1.31 Inorganic Zinc/Epoxy $2.09 Hot-Dip Galvanizing $1.92 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $2.51 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $3.07
- 64. 64 Life-cycle Cost Maintenance on a ‘practical’ (vs. ideal) cycle - unique to each paint system, as recommended by paint manufacturers NACE Model for NFV and NPV calculations • 4% inflation • 7% interest Maintenance repaint at 5% rust in a moderately industrial environment 30-Year Project Performance
- 65. 65 Life-Cycle Cost ($/ft2) 50-Year Project Performance Coating System $/ft2 Hot-Dip Galvanizing $1.92 Inorganic Zinc $3.21 Inorganic Zinc/Epoxy $4.83 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $6.43 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $7.98
- 66. 66 What Does All of This Mean? Coating System Cost Hot-Dip Galvanizing $19,200 Inorganic Zinc $32,099 Inorganic Zinc/Epoxy $48,261 Inorganic Zinc Primer/ H-B Epoxy/Acrylic Urethane $64,302 Acrylic WB Primer/Acrylic WB Intermediate/Acrylic WB Topcoat $79,802
- 67. Duplex Systems: Painting & Powder Coating Hot-Dip Galvanized Steel
- 68. 68 Why Paint a Perfectly Good Galvanized Part? Aesthetics • Architects decision Identification Hostile Environment to Zinc Repair of Existing Galvanized Articles • Extended Life of the Product Light Rail Station
- 69. 69 Galvanized Surface Coating Condition Newly Galvanized Steel Partially Weathered Galvanized Steel Fully Weathered Galvanized Steel Painted Bridge Rail
- 70. 70 Passivation Cycle 1 2 3 Time 0 – 48 hrs. 48 hrs. – 6 mo. 6 mo. – 2 yrs.
- 72. 72 Duplex System Layers Fence Pole
- 73. 73 Duplex System Synergistic Effect Paint Provides Barrier for Galvanized Surface Galvanized Coating Provides Slow Corrosion Under Paint Paint Peeling due to Corrosion is Minimized Paint & Galvanizing together have 1.5x to 2.5x Life of Individual Lifetimes Skaneateles Community Center
- 75. 75 Brooklyn Bridge Date Galvanized 1999 Sector Bridge & Highway Environment Industrial Location New York, NY
- 76. 76 CALTRANS District 7 HQ Date Galvanized 2004 Sector Building & Architecture Environment Urban Location Los Angeles, CA
- 77. 77 The Cloud at Fashion Show Mall Date Galvanized 2003 Sector Building & Architecture Environment Urban Location Las Vegas, NV
- 78. 78 Harrisburg Airport Transportation Facility Date Galvanized 2004 Sector Building & Architecture Environment Urban Location Harrisburg, PA
- 79. 79 Cell Towers – Tree Application Date Galvanized 2004 Sector Electrical, Utility & Communication Environment Rural Location California
- 80. 80 Leprino Foods Date Galvanized Unknown Sector Food & Agriculture Environment Rural Location Waverly, NY
- 81. 81 Piers 1 & 21 Replacement Date Galvanized 2002 Sector Water & Marine Environment Marine Location Norfolk, VA
- 82. 82 AGA Resources 1-800-HOT-SPEC (800.468.7732) aga@galvanizeit.org www.galvanizeit.org Technical Library Galvanizing Insights e-Newsletter