Galvanize It! Seminar

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Galvanize It! Seminar

• American Galvanizing Association

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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

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Continuing Education Credit
American Institute of Architects Learning Units
(HSW)
National Council of Examiners for Engineering
Surveying Professional Development Hours
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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.

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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.

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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.

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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

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Tour of the City
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The Corrosion Problem
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The Corrosion Problem
Bridge in Denver, CO
Bridge in Denver, CO
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The Corrosion Problem
Corroded Trolley
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The Corrosion Problem
Coors Field Denver, CO
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The Corrosion Problem
Corroded Pier
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The Corrosion Problem
Williamsburg Bridge - New York City, NY
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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

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The Solution Hot-Dip Galvanizing
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Barrier Protection
Weathered Guardrail
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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).
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Cathodic Protection
Exposed Steel is Protected
Zinc Coating
Bare Steel

• With a cathodically protective coating, such as
  galvanized steel, damaged areas will be protected
  by the surrounding zinc

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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.

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Long-Lasting Zinc Protection

• Barrier
• Cathodic
• Zinc Patina

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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
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HDG Process Galvanizing

• Steel articles are immersed in a bath of molten
  zinc ( 830 0F)
• gt 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
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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.

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Hot-Dip Galvanized Coating Properties
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Metallurgical Bond
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Edge Protection
Same thickness at corner
Micrograph of galvanized edge
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Additional Benefits of HDG

• Complete Coverage

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Additional Benefits of HDG

• Variety of sizes and shapes

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Additional Benefits of HDG

• Availability

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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 Earths crust
• The longevity of galvanizing means no additional
  energy exerted or waste created maintaining
  galvanized structures

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Estimated Service Life of HDG
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Other Zinc Coatings for Corrosion Protection
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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
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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
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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
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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
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Electroplated

• Strip, sheet, or small parts
• Smooth finish
• Slightly more expensive than sheet galvanized
• Good formability
• Paintable

Electroplating Application
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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
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Other Zinc Coatings
Metallizing
Sheet Galvanized
Hot-Dip Galvanized
Zinc-Rich Paint
Electroplated
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Design Fabrication
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(No Transcript)
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Materials Suitable forHot-Dip Galvanizing
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Hot-Dip Galvanized Fasteners

• Hot-dip galvanized fasteners are recommended for
  joining HDG structurals

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Steel Reactivity
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Coating Appearance
Newly Galvanized
Newly Galvanized
Dull Coating
No Spangle
Newly Installed
Newly Galvanized
Highly Spangle
Shiny Dull Coating
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Combining Different Materials
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Weathering of Galvanized Steel
Photo taken 12/18/02
Photo taken 03/28/03
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Dissimilar Thicknesses

• Different thickness
• Zinc bath temperature at different times
• Similar thickness
• Maintain original shape

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Galvanizing Oversized Pieces
Progressive Dipping
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Material Handling
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Venting Drainage
Vent
Drain
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Specifications Inspection
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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

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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

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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

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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.

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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

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Hot-Dip Galvanizing

• Costs Less Lasts Longer

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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

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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

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Initial Cost

• Material
• Shop cleaning labor
• Shop application
• Field labor

Pneumatic Bulk Trailers
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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
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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

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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
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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
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Duplex SystemsPainting Powder Coating
Hot-Dip Galvanized Steel

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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
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Galvanized Surface Coating Condition

• Newly Galvanized Steel
• Partially Weathered Galvanized Steel
• Fully Weathered Galvanized Steel

Painted Bridge Rail
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Passivation Cycle
Time 0 48 hrs. 48 hrs. 6 mo. 6 mo. 2
yrs.
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Sweep Blasting
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Duplex System Layers
Fence Pole
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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
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Galvanized Steel Project Applications
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Brooklyn Bridge
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CALTRANS District 7 HQ
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The Cloud at Fashion Show Mall
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Harrisburg Airport Transportation Facility
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Cell Towers Tree Application
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Leprino Foods
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Piers 1 21 Replacement
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AGA Resources