Galvanize It

8/12/2019 Galvanize It

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Galvanize It! Seminar

American GalvanizingAssociation


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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-fabricationgalvanizers, fabricators, architects, specifiers,and engineers

The AGA provides technical support on today's

innovative applications and state-of-the-arttechnological developments in hot-dipgalvanizing for corrosion control


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American Institute of ArchitectsLearning Units (HSW)

Continuing Education Credit

National Council of Examiners forEngineering & SurveyingProfessional Development Hours


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Continuing Education

AIA/CES Policy on Endorsement:The followingprogram is registered with the AIA/CES anddoes not include content that may be deemedor construed to be an approval, sponsorship, orendorsement of any material of construction orany method or manner of handling, using,distributing, or dealing in any material orproduct.


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Continuing Education

The American Galvanizers Association has metthe standards and requirements of the

Registered Continuing Education ProvidersProgram. Credit earned upon completion of thisprogram will be reported to RCEPP. A certificateof completion will be issued to each participant.

As such, it does not include content that may bedeemed or construed to be an approval orendorsement by NCEES or RCEPP.


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Learning Objectives

At the end of this presentation you will be ableto:

Recognize the corrosion issues confronting theUnited States

Describe how zinc coatings, specifically hot-dipgalvanizing, can protect against steel corrosion

Incorporate sound corrosion protection into thedesign of steel products that can significantlydecrease maintenance costs over the life of astructure


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Tour of the City


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The Corrosion Problem


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Bridge in Denver, CO

Bridge in Denver, CO


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Corroded Trolley


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Coors Field Denver, CO


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Corroded Pier


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Williamsburg Bridge - New York City, NY


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Corrosion Costs

NACE, CCTechnologies, &FHWA jointly

produced a report in2001 detailing thecosts of corrosion $297 billion USD

annually 3.1% of US GDP

(1998)

Hazardous Public safety, property

damage,

environmentalcontamination

Natural Resources Waste production,

increased energyconsumption

Public Outcry Traffic, inconvenience


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The Solution: Hot-DipGalvanizing


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Barrier Protection

Weathered Guardrail


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Cathodic Protection: Galvanic Series

ZINC -Anode

STEEL -Cathode

This arrangement ofmetals determines whatmetal will be the anodeand cathode when the two

are put in a electrolytic cell(arrangement dependenton salt water aselectrolyte).


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Cathodic Protection

With a cathodically protective coating, such asgalvanized steel, damaged areas will beprotected by the surrounding zinc

Zinc Coating

Bare Steel

Exposed Steelis Protected


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HDG Process

Steel is dipped in a series of tanks including solutions

that remove impurities from the steel surface. Thegalvanizing reaction only occurs on perfectly clean steel.

The steel is inspected after galvanizing to ensureconformance to the appropriate specifications.


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Long-Lasting Zinc Protection

Barrier

Cathodic

Zinc Patina

Zinc Patina Cathodic

Barrier

Long-lastingProtection


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HDG Process: Surface Prep

Zinc-iron metallurgicalbond only occurs on cleansteel

Degreasing Removes dirt, oils, organic

residue

Pickling

Removes mill scale andoxides

Fluxing Mild cleaning, provides

protective layer

Caustic cleaning


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HDG Process: Galvanizing

Steel articles areimmersed in a bath ofmolten zinc ( 830 0F)

> 98% pure zinc, minorelements added forcoating properties (Al, Bi,Ni)

Zinc reacts with iron inthe steel to formgalvanized coating.

Zinc bath removal


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HDG Process: InspectionSteel articles areinspected aftergalvanizing to verify

conformance toappropriate specs.

Surface defects easilyidentified through visualinspection.

Coating thickness verifiedthrough magneticthickness gaugereadings.


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Hot-Dip Galvanized Coating

Properties


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Metallurgical Bond


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Edge Protection

Micrograph of galvanized edge

Same thickness at corner


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Additional Benefits of HDGComplete Coverage


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Additional Benefits of HDG

Variety ofsizes and

shapes


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Additional Benefits of HDG

Availability


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Galvanizing is Green

Zinc is 100% recyclable as isthe 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 energyexerted or waste createdmaintaining galvanizedstructures


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Estimated Service Life of HDG


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Other Zinc Coatings forCorrosion Protection


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Metallizing

Shop or in-fieldapplication

Suitable for very largepieces

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 tomake performanceclaims

Zinc Rich Paint Application


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Sheet Galvanized

ASTM A653specify total coating weights,most common G60 and G90

Weights represent total coating weight for both sidesof the sheet

Coating Weight(ounces/sq. ft.)

CoatingThickness per

Side (mils)G60 0.60 0.54

G90 0.90 0.81


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Electroplated

Strip, sheet, or smallparts

Smooth finish

Slightly moreexpensive than sheetgalvanized

Good formabilityPaintable

Electroplating Application


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Zinc (Mechanical) Plating

Similar toelectroplating

used for fasteners andsmall parts

Parts are tumbled indrum with zinc

powder and glassbeads

mechanically bondedzinc

Mechanical Plating Application


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Other Zinc Coatings

Metallizing

Hot-Dip Galvanized

Zinc-Rich Paint

Sheet Galvanized

Electroplated


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Design & Fabrication


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Materials Suitable for

Hot-Dip Galvanizing


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Steel Reactivity


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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 atdifferent 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

Drain

Vent


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Specifications & Inspection


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ASTM Standards for Galvanizing

Galvanized Products ASTM A 123general

ASTM A 153small parts

ASTM A 767rebar

Supporting Specifications ASTM A 143embrittlement

ASTM A 384distortion ASTM A 385high-quality coatings

ASTM A 780repair

ASTM D 6386surface prep for painting over


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ASTM A 123

Standard Specificationfor Zinc (Hot-DipGalvanized) Coatings on

Iron and Steel Products

Coating Thicknessmaterial category and steel

thickness Finishcontinuous, smooth, uniform

Adherenceshould be tightly adherent through allexpected uses of article


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ASTM A 767

Standard Specificationfor Zinc-Coated(Galvanized) Steel Bars

for ConcreteReinforcement

Coating Thicknesssmooth or deformed (no wire),bar size

Chromatingprevent reaction between fresh cementand recently galvanized material

Bend Diametersflaking and cracking due tofabrication are not rejectable.


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ASTM A 780

Standard Practice for Repair of Damagedand Uncoated Areas of Hot-Dip GalvanizedCoatings

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 soldergood for small areas, closely mirrorstypical HDG coating appearance

Metallizingexcellent 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 paperpaint industry surveynationwide

Standard mix of steelproducts (structural, tubing,plate)

10,000 ft2project


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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 calculatesinitial and life-cycle cost for the specified

paint systems and hot-dip galvanizing


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Initial Cost

Material

Shop cleaning labor

Shop applicationField labor

Pneumatic Bulk Trailers


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Initial Cost ($/ft2)

Coating System $/ft2

Inorganic Zinc $1.31

Inorganic Zinc/Epoxy $2.09Hot-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 manufacturersNACE Model for NFV and NPVcalculations

4% inflation

7% interest

Maintenance repaint at 5% rust in amoderately industrial environment

30-Year Pro ect Performance


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Life-Cycle Cost ($/ft2)

50-Year Project PerformanceCoating 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 WBIntermediate/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 $32,099Inorganic Zinc/Epoxy $48,261

Inorganic Zinc Primer/

H-B Epoxy/Acrylic Urethane $64,302Acrylic WB Primer/Acrylic WBIntermediate/Acrylic WB

Topcoat

$79,802


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Duplex Systems:

Painting & Powder Coating

Hot-Dip Galvanized Steel


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Why Paint a Perfectly Good

Galvanized Part?Aesthetics

Architects decision

Identification

Hostile Environmentto Zinc

Repair of Existing

Galvanized Articles Extended Life of the

ProductLight Rail Station


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Galvanized Surface

Coating Condition

Newly GalvanizedSteel

Partially WeatheredGalvanized Steel

Fully Weathered

Galvanized Steel

Painted Bridge Rail


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Passivation Cycle

1

2

3

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 EffectPaint Provides Barrier forGalvanized Surface

Galvanized Coating

Provides Slow CorrosionUnder Paint

Paint Peeling due toCorrosion is Minimized

Paint & Galvanizingtogether have 1.5x to 2.5xLife of Individual Lifetimes Skaneateles Community Center


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Galvanized SteelProject Applications


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Brooklyn Bridge

Date Galvanized1999

Sector

Bridge &Highway

EnvironmentIndustrial

LocationNew York, NY


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CALTRANS District 7 HQ

Date Galvanized2004

SectorBuilding &Architecture

EnvironmentUrban

LocationLos Angeles, CA


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Harrisburg Airport

Transportation FacilityDate Galvanized2004

Sector

Building &Architecture

EnvironmentUrban

LocationHarrisburg, PA


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Cell TowersTree Application

Date Galvanized2004

Sector

Electrical, Utility &Communication

EnvironmentRural

LocationCalifornia


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Leprino Foods

Date GalvanizedUnknown

Sector

Food & Agriculture

EnvironmentRural

LocationWaverly, NY


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Piers 1 & 21 Replacement

Date Galvanized2002

SectorWater & Marine

EnvironmentMarine

LocationNorfolk, VA


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Documents

Galvanize It