Hot Dipped Galvanized HDG Glossary

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A

AASHTO – American Association of State Highway and Transportation Officials

Abrasion-resistance – the ability of the galvanized coating to resist damage caused by contact with hard, rough, or coarse media or objects

Abrasive blasting – the process of using a forceful stream of particles, available in varying hardness, to remove residue and contaminants from steel surfaces to prepare for galvanizing and/or to profile steel surfaces for paint application

Adherence – the act, action, or quality of zinc bonding to steel, measured in pounds per square inch or mega pascals (MPa)

Aggressive environment – an environment that is particularly corrosive

Alloy layers – the interior layers of the galvanized coating comprised of iron/zinc intermetallics formed when molten zinc reacts with iron in the steel

Aluminum – element found in the galvanizing bath (added to molten zinc through a product commonly called “brightener bar”) that gives the hot-dip galvanized coating a shiny appearance

Aluminum-killed steel – steel treated with aluminum as an oxidizing agent in order to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification

Amphoteric – having the characteristics of an acid and a base and capable of reacting chemically either as an acid or a base

Anion – a negatively charged ion, especially the ion that migrates to an anode in electrolysis

Anode – the electrode of an electrolytic cell at which corrosion (oxidation) occurs, positive current flows from the anode through the electrolyte to the cathode; with respect to hot-dip galvanizing, anode refers to zinc, which corrodes sacrificially to protect steel

Anodic – exhibiting the properties of an anode; zinc is anodic to steel

Application – the act of putting to use; specifically, the use to which galvanized steel will be put

Aqueous – relating to, similar to, containing, or dissolved in water; watery

Ash – solid byproduct formed in the galvanizing process, consisting primarily of zinc oxides, that remains on the surface of the kettle; commonly referred to as “skimmings”

Ash inclusions – ash or skimmings carried out of the kettle on parts; ash inclusions remain solidified in the coating

Assemblies – the fitting together of manufactured parts into a complete structure, machine, or unit of a machine; assemblies sometimes require specific design features in order to be optimally galvanized

ASTM – American Society of Testing and Materials

Atmosphere – a surrounding influence or environment that affects the rate of corrosion; frequency and amount of moisture, humidity, chlorides, sulfides, and wind are some of the atmospheric components affecting corrosion rates

AZA – American Zinc Association

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B

Barrier protection – the protection provided by inhibiting oxidation (rust) by an insoluble top-coating such as zinc, which isolates steel from any electrolytes that would assist the corrosion process

Bond strength – the strength with which two or more items are joined; the resistance that must be overcome in order to separate the joined materials, e.g. steel and zinc-iron alloy layers of the galvanized coating, or galvanized reinforcing steel and concrete

Brown staining – reaction between exposed intermetallic layers (specifically the iron portion of the layers) and oxygen, resulting in surface color changes from gray to brown

Bracing – metal that is attached to a fabrication prior to galvanizing in order to provide support so that the steel does not change shape during heating and cooling; can be temporary or permanent

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C

Camber – the condition of having an arched surface

Carbon – naturally occurring element commonly found in steel

Cast iron – a generic term for a large family of cast ferrous alloys

Cast steel – steel in the form of an object at or near finished shape, produced by pouring molten steel into a mold

Casting – an object at or near finished shape obtained by solidification of a metal or alloy in a mold

Cathode – the electrode of an electrolytic cell at which reduction occurs; positive current flows from the anode (zinc) through the electrolyte to the cathode (steel)

Cathodic – exhibiting properties of a cathode; steel is cathodic in relation to zinc

Cathodic protection – reduction or prevention of corrosion of a metal surface by making it a cathode in an electrolytic cell, using either a galvanic or impressed current; zinc cathodically protects steel, i.e. sacrificially giving up electrons to protect the steel from corrosive attack

Caustic cleaning – the cleaning of steel in a solution with high alkalinity; in the hot-dip galvanizing process, organic residues are removed by immersing steel in a tank of caustic solution

Centrifuging – the process of removing excess zinc from small hot-dip galvanized parts by placing them in a perforated, rapidly spinning cylindrical container

Chemical cleaning – the process of immersing steel in chemical solvents to remove (dissolve) residues that would otherwise prevent the galvanized coating from forming

Chemical composition – the makeup of steel, broken down into naturally occurring elements; usually carbon, manganese, phosphorous, silicon as primary elements

Chromate quenching – treating metal in a tank of containing a solution of chronium compounds to produce a conversion coating consisting of trivalent and hexavalent chromium compounds; chromate passivations sometimes are used on galvanized reinforcing bar to control reactions between zinc and concrete while the concrete cures, particularly the hydrogen evolution that adversely affects bonding; chromate quenching other galvanized articles prevents the formation of wet storage stain

Chromating – chromate quenching a galvanized article

Cleaning – the process of chemically or mechanically removing unwanted residue or contaminants (mill scale, rust, dirt, oil) from the surface of a steel article prior to galvanizing

Cleaning solutions – liquids used to remove unwanted residue or contaminants (mill scale, rust, dirt, oil) from the surface of steel prior to galvanizing, typically alkalai caustic solution, hydrochloric or sulfuric acid, and zinc ammonium chloride flux solution

Coating thickness – the thickness of the zinc coating, measured in mils (0.001 inches) or micrometers (10-6 meters)

Cold-galvanizing – See zinc-rich paint

Cold-rolled steel – steel that has been produced from a hot-rolled pickled coil and given substantial cold reduction at room temperature; cold-rolled steel is characterized by improved surface smoothness, greater uniformity in thickness and improved mechanical properties when compared to hot-rolled steel

Cold-working – bending or forming ambient-temperature steel; this action induces stresses that may be released during the galvanizing process

Containment – the act, process, or means to keep within prescribed limits

Contraction – the shrinkage of steel due to cooling of the part after removal from the galvanizing kettle

Corrosion – the chemical or electrochemical reaction between a material and its environment that produces a deterioration of the material and its properties; zinc chemically reacts with elements in the atmosphere, thereby sacrificially corroding to prevent underlying steel corrosion

Cracking (concrete) – the breaking of concrete due to the expansive forces caused by the formation of iron-oxide corrosion products on unprotected reinforcement bars

CSA – Canadian Standards Association

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D

Delta layer – the second layer of zinc-iron alloy growth from the base steel formed during the galvanizing process; the Delta layer’s chemical composition is approximately 90% zinc and 10% iron; the Delta layer is 60% harder than the base steel it protects from abrasion and corrosion

Design – to create, fashion, execute, or construct steel according to plan so that it will yield a quality hot-dip galvanized coating

Diamond Pyramid Number – (DPN) system of assigning values to metals quantifying their hardness

Dissimilar metals – two or more different metals in contact; due to varying surface conductivity, one or more metals may experience accelerated corrosion; because zinc is high in the galvanic series (see Galvanic Series of Metals), it preferentially corrodes to protect most dissimilar metals

Dissolution – the act of dissolving, sundering, or separating into component parts; separation

Distortion – any deviation from an original size, shape or contour that occurs when the application of heat during the galvanizing process releases stress from the steel induced in the fabrication process or during the steel-making process; distortion is of concern when galvanizing asymmetric structural shapes and/or fabrications

Double-dipping (see progressive-dipping) – the act of dipping steel, too large in one dimension to completely fit into the galvanizing kettle, more than once in cleaning solutions and molten zinc metal in order to produce a coating that covers the entire surface of the steel

Drainage – the act, process, or mode of becoming emptied or freed of cleaning solutions and/or zinc

Dross – byproduct of the galvanizing process that forms by reactions between zinc and loose particles of iron; dross may exist at all depths of the kettle, but usually sinks to the bottom

Dross inclusions – dross that is carried out on the work upon removal from the galvanizing kettle

Drossing – removing dross buildup from the bottom of the kettle

Dry galvanizing – dipping steel in an aqueous zinc ammonium chloride solution and then thoroughly drying before immersing in the molten zinc bath

Ductile iron – molten iron treated with an element such as magnesium or cerium to induce a measurable degree of ductility to the metal; these additives do not affect galvanizeability

Ductility – the ability of a material to be formed without fracturing; galvanized steel is ductile within certain recommended bending radii

Duplex systems – galvanized steel that has been coated with an additional corrosion-inhibiting product, typically liquid or powder paint; the two separate coating systems work synergistically to provide enhanced corrosion protection

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E

Electrical isolation – separating two conductive materials from electrical contact; galvanized steel is sometimes electrically isolated in order to prevent rapid consumption of the zinc coating

Electrode – see anode or cathode, whichever is appropriate

Electrolyte – an ionized chemical substance or mixture, usually liquid, that will conduct electric currents; water, soil, or many chemical solutions

Embrittlement – reduction in the normal ductility of a metal due to a physical or chemical change that may occur when cold-worked steel is immersed in molten zinc in the galvanizing kettle

Environment – the complex of physical, chemical, and biotic factors (climate, soil, living things) that act upon metal and ultimately affect the corrosion rate

Eta layer – the fourth, outer layer of the galvanized coating solely comprised of zinc

Excess zinc – extra amounts of zinc that may accumulate on the steel because of chemical composition of the steel or the profile/design of the steel and/or fabrication

External venting – holes that prevent high-pressure gas buildup in enclosed fabrications dipped in the molten zinc of the galvanizing bath

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F

Fabrication – steel configurations constructed from diverse and usually standardized steel members

Fasteners – manufactured steel products (bolts, nails, etc.) used to connect two or more steel members

Fatigue strength – the maximum stress that can be sustained for a specified number of cycles without failure, the stress being completely reversed within each cycle unless otherwise stated

Faying surfaces – the surface of a piece of metal (or a member) in contact with another to which it is or is to be joined

Ferrous metals – metals containing iron

Finishing – final stages of inspection and preparing galvanized steel so that it complies with specification(s)

Flux – chemicals used to protect steel from oxidation prior to entering the molten zinc-containing kettle

Flux inclusions – Flux carried out onto the work from the top flux blanket incorporated in the ‘wet’ process; occurs only in the ‘wet’ galvanizing process

Fluxing – the process by which steel is dipped in aqueous zinc ammonium chloride to remove undesirable substances and to protect it from further oxide formation prior to entering the galvanizing bath

Forged steels – steels formed by plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies

Fresh water – sodium-chloride-free water, especially when considered as a natural resource

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G

Galling – a condition whereby excessive friction between high spots on two different steel parts results in localized welding

Galvanic corrosion – corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte solution, or two similar conductors in dissimilar electrolytes

Galvanic Series of Metals – a listing of metals and alloys arranged according to their relative electrode potentials in a specified environment; indicates what metal(s) will corrode first when two or more metals are in contact

Galvanizing – the act of coating steel with zinc in order to provide barrier and cathodic protection from corrosion

Galvanizing temperature – the temperature at which the molten zinc bath is kept in order to react with the steel; typically, this temperature is between 830 F (443 C) and 850 F (454 C)

Gamma layer – the first layer of zinc-iron alloy growth from the base steel formed during the galvanizing process; the chemical composition of this layer is approximately 75% zinc and 25% iron; the Gamma layer has a DPN of 250, compared to the base steel’s DPN of 159

Grinding – mechanically removing material from a work-piece with a grinding wheel or abrasive belt

Grit-blasting – abrasive blasting with small irregular pieces of steel, malleable cast iron or hard nonmetallic materials

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H

Handling – the process by which steel articles are carried throughout the galvanizing facility, by chain, wire, hook, or racked in a fixture

Hardness – resistance of metal to plastic deformation, usually by indentation; the term may also refer to stiffness or temper, or to resistance to scratching, abrasion or cutting

Heat-treating – heating and cooling a solid metal or alloy in such a way as to obtain desired conditions or properties

High-strength low-alloy (HSLA) steel – steels with a high yield point and low percentages (<1.25%) of other alloying components

High-strength steel – steels that have a tensile strength over 150 ksi (1100 MPa)

Hinges – a jointed or flexible device upon which a door, lid, or other swinging part turns

Holding devices – fixtures used to connect fabrications/parts to be galvanized to handling equipment in the galvanizing facility

Hot-rolled steel – steel deformed plastically at such a temperature and strain-rate that re-crystallization takes place simultaneously with the deformation, thus avoiding strain-hardening; this is the most common type of steel galvanized

Hydrochloric acid – solution used in the cleaning stages of the galvanizing process and consisting of one hydrogen ion and one chloride ion (chemical formula: HCl) in mixture with water

Hydrogen embrittlement – a condition of low ductility in metals resulting from the absorption of hydrogen

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I

Identification – marking/labeling steel so that different customer products can be distinguished from one another after galvanizing

Impact resistance – the ability to avoid damage due to contact with a forceful motion or object; galvanized coatings’ uppermost, pure zinc Eta layer is relatively soft and absorbs impact shock, protecting the underlying alloy layers

Impurities – elements or compounds in which their presence is undesired

Insoluble – not soluble; in capable or difficult of being dissolved, as by liquid; as, chalk is insoluble in water

Inspection – coating thickness and surface condition verifications

Intermetallic – interior layers of the galvanized coating that have distinct proportions of the alloying metals iron and zinc; e.g. Delta, Gamma & Zeta layers

Internal stress – also known as residual stress, stress present in a steel member or fabrication that is free of external forces or thermal gradients

Internal venting – holes on the inside of enclosed fabrications that allow cleaning solutions, zinc, and any gases to freely flow throughout the structure

ISO: International Organization for Standardization – A network of national standards institutes from 140 countries working in partnership with international organizations, governments, industry, business and consumer representatives. The source of ISO 9000 and more than 13,000 international standards for business, government and society. Click here to view the Foreign Specification & ASTM Cross-Reference Chart.

IZA – International Zinc Association

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K

Kettle – molten zinc-filled tank where the metallurgical bonding of zinc and steel takes place

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L

Lifting points – connectors (sometimes temporary) directly on the steel article that aid the galvanizer in handling the article throughout the galvanizing process

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M

Machined surfaces – surfaces cleaned or otherwise altered by a power-driven machine

Malleable iron – iron that permits plastic deformation in compression without rupture

Manganese – a grayish white, usually hard and brittle metallic element found in steel that resembles iron but is not magnetic

Masking – using a material to produce intentionally ungalvanized areas, typically used in areas that are to be welded, on faying surfaces, or areas where the galvanized coating is not necessary for uniform corrosion protection

Matte – dull, lacking or deprived of shine; matte-gray galvanized appearance may result from steel chemistry or may be intentionally induced when the galvanized steel’s use defines reflectivity limits

Mechanical cleaning – removing residues or impurities from steel using mechanical force such as grinding or sand blasting

Mechanical properties – the properties of a material that reveal its elastic and inelastic behavior when force is applied, thereby indicating its suitability for mechanical applications; for example, elasticity, tensile strength, elongation, hardness, and fatigue limit

Metalizing – forming a metallic coating by atomized spraying with molten zinc or by vacuum deposition; also called spray metalizing; applying an electrically conductive metallic layer to the surface of another material

Metallurgical – relating to the study of metals and their properties in bulk an at the atomic level

Metallurgical bond – the bonding of iron/zinc intermetallic layers to the base steel

Mill lacquer – organic protective coating applied to steel parts, usually pipes or tubes, to protect the parts during shipping; this material cannot be removed by the usual galvanized cleaning methods

Mill scale – a heavy, imbedded iron oxide layer formed during hot fabrication or heat-treatment of steels

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N

Nickel – common element found in the galvanizing kettle to suppress the reactivity of silicon and phosphorus in the steel

Notching – cutting out various shapes from the edge of a strip, blank or part

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O

Organic contaminants – surface impurities (dirt, grease, oil, paint markings) that will hinder the formation of the galvanized coating, usually removed in the caustic cleaning stages of the galvanizing process

Overlapping surfaces – created when one area of a metal structure is covered by the surface of another metal structure

Overtapping – cutting female fastener threads of nuts or threaded holes larger than standard to account for the increased diameter of the galvanized (male) mating part

Oxidized – to combine with oxygen; make into an oxide

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P

Passivation – changing chemically active metal surfaces to a much less reactive state (see phosphating and chromating)

Patina – relatively insoluble zinc carbonate layer that forms as the galvanized coating weathers, providing added corrosion protection and abrasion resistance

Phosphating – forming an adherent phosphate coating on a metal by immersion in a suitable aqueous phosphate solution, commonly used to promote better adhesion of paint to galvanized steel

Phosphorus – naturally occurring element commonly found in steel, particularly reactive in molten zinc metal

Pickling – removing surface oxides from metals by immersion in ambient temperature, dilute hydrochloric acid or hot (180 F/82 C) sulfuric acid

Pinhole – small hole left in a weld area that allows low viscosity liquids to enter and become pressurized under the high temperature conditions of the molten zinc bath

Pitch diameter – the diameter of a fastener cylinder prior to threading

Pitted surfaces – areas of metal where small, sharp cavities exist, usually formed by corrosion

Polarization – the partial or complete polar separation of positive and negative electric charges in a nuclear, atomic, molecule or chemical system

Post-treatment – subjecting the steel to specific processes after it has been galvanized (see quenching, phosphating, and chromating)

Pre-flux – the process of fluxing steel before it enters the galvanizing kettle as opposed to using a top-flux layer, which would be located on top of the molten zinc in the kettle

Pre-treatment – subjecting steel to specific processes before galvanizing

Progressive dipping – the act of dipping steel more than once in cleaning solutions and molten zinc metal in order to produce a coating that covers the entire surface of the steel; commonly done when the steel article/fabrication is too large to fit entirely into the kettle in one dip

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Q

Quenching – rapid cooling by dipping galvanized steel in a tank filled with a liquid solution; usually water or a dilute chromate or phosphate solution

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R

Racking – the process of arranging articles on a rack in order to transport them more efficiently through the galvanizing process

Reduce – to remove oxygen from (a compound)

Reinforcing steel – steel embedded in concrete to increase the concrete’s load strength

Repair – performing finishing work after galvanizing in order to meet standards or specifications, or coating areas of steel that have been exposed due to post-galvanizing fabrication, installation, or extremely rough handling

Residue – contaminants (oil, grease, dirt, rust, mill scale) that unless removed, will prevent complete galvanizing of the steel surface

Return current path – the path through which the current in an electric cell returns to the source

Rinsing – removing any active solution from the surface of steel by immersion in water Rust -* corrosion product consisting of hydrated iron oxides; this term is applicable only to ferrous (iron-containing) alloys

Rust – corrosion product consisting of hydrated iron oxides; this term is applicable only to ferrous (iron-containing) alloys

Rust staining – reaction between exposed intermetallic layers (specifically the iron portion of the layers) with oxygen, that cause mild red or brown staining.

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S

Salt water – water with high concentrations of sodium chloride or other salts

Scale – a thick layer of imbedded oxidation (rust) products on metals

Seal-welding – a weld used primarily to obtain tightness and prevent the flow of cleaning solutions and zinc into otherwise enclosed areas, to prevent flash steaming that causes localized ungalvanized areas

Service-life – anticipated length of time zinc will protect steel; the amount of time until enough of the galvanized coating is consumed and 5% of the substrate steel surface area shows signs of rust

Shearing – the type of force that causes or tends to cause two parts of the same body that are touching along a boundary to slide relative to each other in a direction parallel to their plane of contact

Shot-blasting – abrasive blasting steel with metal shot, usually to remove deposits or mill scale more rapidly or more effectively than can be done by sand-blasting or chemical cleaning

Silicon – naturally occurring element commonly found in steel; silicon is particularly reactive in molten zinc metal

Silicon-killed steel – steel treated with silicon as an oxidizing agent in order to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification

Skimmings (ash) – galvanizing byproduct comprised mainly of zinc oxides; skimmings are recyclable

Skip-welding – alternating the weld so that it is not continuous or complete

Spalling (concrete) – the complete failure of concrete due to the expansive forces caused by the formation of corrosion products on unprotected reinforcement bars

Soluble – susceptible of being dissolved in a fluid; capable of solution; as, some substances are soluble in alcohol which are not soluble in water

Spangle – the characteristic crystalline form exhibited by the solidified, hot-dipped zinc coating

Stainless steel – type of steel alloy that contains significant amounts of chromium and/or nickel and is typically very corrosion resistant due to its ability to passivate upon atmospheric exposure

Stamping – a general term covering almost all press operations, including blanking, shearing, hot-forming, cold-forming, drawing, bending, coining

Stenciling – the process by which lettering or a design through which a substance (ink, paint, or metallic powder) is forced onto a surface to be printed; commonly used to mark steel fabrications but generally does not remain after the galvanizing process

Storage – the area where galvanized articles are staged for pick-up or delivery

Strain-age embrittlement – the loss in ductility accompanied by an increase in hardness and strength that occurs when low-carbon steel (especially rimmed or capped steel) is aged following plastic deformation; the degree of embrittlement is a function of aging time and temperature, occurring in a matter of minutes at the galvanizing temperature but requiring a few hours to years at room temperature

Stress-relieving – heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling slowly enough to minimize the development of new residual stresses

Structural – steel member of specific cross-sectional dimensions used in fabrication and/or construction, (e.g. H-beam, angle, I-beam, W-flange)

Structural steel shape – piece of steel of any specific design accepted as standard by the structural branch of the steel industry

Sulfuric acid – solution used in the cleaning stages of the galvanizing process that consists of two hydrogen ions and one sulfate ion (chemical formula: h2SO4) in a water mixture

Surface condition – state of the surface of the steel

Surface preparation – stages of cleaning that prepare the steel for finishing (galvanizing)

Sweep – direction or departure of a curve, a road, an arch, or the like, away from a rectlinear line

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T

Tank – container for chemicals used in the galvanizing process; steel is dipped sequentially in solution-containing tanks

Temporary bracing – metal that is attached to a fabrication prior to galvanizing in order to provide added support so that the steel does not change shape during heating and cooling; temporary bracing is removed after galvanizing.

Thermal expansion – the process by which steel becomes larger upon heating

Thermodynamic – characteristics of or resulting from the conversion of heat into other forms of energy

Threaded parts – parts such as bolts and rods that allow nuts to be screwed on to one or both ends

Touch-up – performing finishing work after galvanizing in order to meet standards or specifications, or coating areas of steel that have been exposed due to post-galvanizing fabrication, installation, or extremely rough handling

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V

Venting – providing holes in fabrications to be galvanized to allow entrapped, heated liquids and gases to escape as pressure increases

Vibrating – the process of removing excess zinc by rapidly shaking galvanized articles

Viscosity – the property of resistance to flow in a fluid or semi-fluid state

Voluminous – having great volume, fullness, or size

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W

Warping – twisting or curving of steel originally flat or straight

Weathering steel – corrosion-resistant steel that initially corrodes; the presence of corrosion products then limits the further oxidation of the metal

Weepage – the leaching out of trapped liquid solutions in galvanized structures, primarily through pinholes or gaps in welds that were not sealed over by zinc

Weld beads – deposits of filler metal from a welding pass

Weld flux – material used to prevent the formation of, or to dissolve and facilitate removal of, oxides and other undesirable substances

Weld residue – impurities left from the welding process; weld residue will inhibit localized formation of the galvanized coating.

Weld slag – material resulting from the combination of weld material and weld flux; weld slag will inhibit localized formation of the galvanized coating

Welding – joining two or more pieces of material by applying heat or pressure, or both, with or without filler material, to produce a localized union through fusion or recrystallization across the interface

Wet galvanizing – using a liquid flux layer floated on top of the molten zinc; in the galvanizing process, final cleaning occurs as the material passes through the flux blanket before entering the molten zinc bath

Wet storage stain – white surface oxide and hydroxide that forms on newly galvanized steel when excessive moisture is present in poorly ventilated storage

Wheel-abrading – mechanical cleaning method used to remove small amounts of residues found on steels by means of a rough, rotating wheel

White rust – white, sticky substance comprised of basic zinc carbonate; forms when galvanized surfaces are constantly covered by water or water containing sulfides or chlorides

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Z

Zinc – major element found in the galvanizing kettle that provides both barrier and cathodic protection for steel

Zinc ammonium chloride – typical component of the flux solution used in the cleaning phase of the galvanizing process

Zinc carbonate patina – relatively insoluble zinc carbonate layer that forms as the galvanized coating weathers, providing added corrosion protection and abrasion resistance

Zinc hydroxide – corrosion product formed in response to the presence of moisture on galvanized articles

Zinc oxide – basic corrosion product formed almost instantaneously on freshly galvanized articles after withdrawal from the molten zinc metal

Zinc patina – relatively insoluble zinc carbonate layer that forms as the galvanized coating weathers, providing added corrosion protection and abrasion resistance

Zinc solder – material used to touch-up and/or repair hot-dip galvanized surfaces

Zinc-iron alloy layers – inner layers of the galvanized coating formed from interdiffusion reactions between iron in the base steel and molten zinc metal, (e.g. Delta, Gamma, Zeta)

Zinc-rich paint – (also called “cold galvanizing”) material used to touch-up and or repair hot-dipped galvanized surfaces, providing barrier protection and some cathodic protection (if the concentration of zinc is above 94% in dry film thickness)

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