GALVALUME Sheet Carbon Steel Specs

6
USS Galvalume sheet is a cold rolled steel sheet with a coating of an aluminum- zinc-silicon alloy, applied by the continuous hot-dip process. The coating gives Galvalume steel sheet the best properties of aluminum - coated and galvanized steel sheets. The presence of aluminum in the aluminum - zinc alloy coating provides improved barrier corrosion resistance and heat reflectivity to the cold rolled steel substrate . The addition of zinc provides a high level of galvanic pro- tection against corrosion at cut edges, cracks and scratches. Galvalume ' s surface has a small, uniform spangle and a smooth , bright appearance that makes it attractive when used for exposed unpainted applications. Long - term economy Because of the two-way protection afforded by the aluminim-zinc coating, Galvalume sheet offers at least twice the service life of galvanized steel with the same coating thickness. In some areas, the service life is extended three to four times. This has been verified by actual atmospheric exposure corrosion tests conducted over a period of more than 17 years in environmental conditions ranging from rural to severe marine atmospheres. These test results are much more signifi- cant than laboratory accelerated tests because they show the performance in the same environments as those encountered in actual service. Observations on test panels exposed for as long as 21 years substantiate the fact that Galvalume offers long term durability. USS Galvalume costs about the same, on a per-square-foot basis, as USS G-90 galvanized sheet. Therefore, because it lasts longer, Galvalume is a low cost-per- year alternative to other coated sheet. a. Galvalume Coating Cross-Section b. Modernized exit end of the Galvalume coating line at the USS Irvin plant near Pittsburgh. The line's new features give USS Galvalume a competitive edge in overall product quality. Galvalume is a trademark of Bethlehem Steel Corp. Convenient availability- Irvin Plant USS makes Galvalume sheet on one of the three coating lines at its Irvin Plant sheet-processing facility. The Irvin Galvalume line is equipped with modern coating equipment and its workers have years of production experience with zinc and aluminum coating. Located in the Pittsburgh area, Irvin provides a conven- ient shipping point for Galvalume sheet. USS Galvalume sheet is available in steel thicknesses from 0.015 inch to 0.052 inch, in widths to 48 inches, with yield strength levels to 80 ksi. (minimum) Two surface finishes are available: regular spangle (small, uniform bright spangle) and extra-smooth (matte finish for applications where critical surface finish is desired). Triple Spot Test Coating Minimum oz./ft2 (g/m2) Designation (total both sides) Al-rich area Zn-rich area Alloy bond layer Steel Coating thickness USS offers two coating weights for most applications, 0.50 ounce per square foot (150 g/m2) and 0.55 ounce per square foot (165 g/m2) as shown in the chart below. Designations for these coatings are AZ50 and AZ55, respectively. The AZ55 coating is specified for unpainted metal buildings. The AZ50 coating, which has a thickness approximately equivalent to a G90 galvanized coating, is recom- mended for prepainted metal building applications, and most other applications. Lighter coating weights are available for special applications that require enhanced formability or weldability. Single Spot Test Minimum oz ./ ft2 (g /m2) Thickness, mil (total both sides ) ( per side)

description

GALVALUME Sheet Carbon Steel Specs

Transcript of GALVALUME Sheet Carbon Steel Specs

Page 1: GALVALUME Sheet Carbon Steel Specs

USS Galvalume sheet is a cold rolledsteel sheet with a coating of analuminum -zinc-silicon alloy, applied bythe continuous hot-dip process. Thecoating gives Galvalume steel sheet thebest properties of aluminum -coatedand galvanized steel sheets.

The presence of aluminum in thealuminum -zinc alloy coating providesimproved barrier corrosion resistanceand heat reflectivity to the cold rolledsteel substrate . The addition of zincprovides a high level of galvanic pro-tection against corrosion at cut edges,cracks and scratches.

Galvalume 's surface has a small,uniform spangle and a smooth , brightappearance that makes it attractivewhen used for exposed unpaintedapplications.

Long -term economyBecause of the two-way protectionafforded by the aluminim-zinc coating,Galvalume sheet offers at least twice theservice life of galvanized steel with thesame coating thickness. In some areas,the service life is extended three to fourtimes. This has been verified by actualatmospheric exposure corrosion testsconducted over a period of more than 17years in environmental conditions rangingfrom rural to severe marine atmospheres.These test results are much more signifi-cant than laboratory accelerated testsbecause they show the performance in thesame environments as those encounteredin actual service. Observations on testpanels exposed for as long as 21 yearssubstantiate the fact that Galvalume offerslong term durability.

USS Galvalume costs about the same,on a per-square-foot basis, as USS G-90galvanized sheet. Therefore, because itlasts longer, Galvalume is a low cost-per-year alternative to other coated sheet.

a. Galvalume Coating Cross-Section

b. Modernized exit end of the Galvalume coating lineat the USS Irvin plant near Pittsburgh. The line's new

features give USS Galvalume a competitive edge inoverall product quality.

Galvalume is a trademark ofBethlehem Steel Corp.

Convenient availability-Irvin PlantUSS makes Galvalume sheet on one ofthe three coating lines at its Irvin Plantsheet-processing facility. The IrvinGalvalume line is equipped with moderncoating equipment and its workers haveyears of production experience with zincand aluminum coating. Located in thePittsburgh area, Irvin provides a conven-ient shipping point for Galvalume sheet.

USS Galvalume sheet is available insteel thicknesses from 0.015 inch to0.052 inch, in widths to 48 inches, withyield strength levels to 80 ksi. (minimum)Two surface finishes are available:regular spangle (small, uniform brightspangle) and extra-smooth (matte finishfor applications where critical surfacefinish is desired).

Triple Spot TestCoating Minimum oz./ft2 (g/m2)Designation (total both sides)

Al-rich area

Zn-rich area

Alloy bond layer

Steel

Coating thickness

USS offers two coating weights for mostapplications, 0.50 ounce per square foot(150 g/m2) and 0.55 ounce per squarefoot (165 g/m2) as shown in the chartbelow. Designations for these coatingsare AZ50 and AZ55, respectively. TheAZ55 coating is specified for unpaintedmetal buildings. The AZ50 coating, whichhas a thickness approximately equivalentto a G90 galvanized coating, is recom-mended for prepainted metal buildingapplications, and most other applications.Lighter coating weights are available forspecial applications that require enhancedformability or weldability.

Single Spot TestMinimum oz ./ft2 (g/m2) Thickness, mil(total both sides) (per side)

Page 2: GALVALUME Sheet Carbon Steel Specs

USS Galvalume sheetqualities (ASTM A792)Commercial QualityGalvalume steel of this quality is intendedprimarily for bending and moderate form-ing applications. Typical applicationsinclude overhead doors, toaster partsand walk-in cooler panels.

Lock Forming QualityGalvalume sheet of this quality is intendedprimarily for use in fabrication where thematerial will be subjected to lock formingor other bending operations that involvesmall bend radii. High speed forming andthe tight bends involved in lock formingimpose severe requirements-in excessof the formability requirements ofCommercial Quality-on both the basemetal and the coating. Typical applicationsinclude ductwork, downspouts, trim partsand brackets.

Structural(Physical) QualityASTM A792

* None specified

M

Structural (Physical ) QualityUSS Galvalume steel sheet of this qualityis intended for use where load-bearingcapability is a consideration in design.It is provided to meet specified mechanicaltest properties including yield strength,tensile strength and elongation. The mini-mum mechanical property requirementsof the various grades when specified toASTM A792 are shown in the table below.Typical applications include metal buildingroofing and siding.

ASTM A792 Specification - Mechanical Properties

Yield StrengthMinimum

Tensile StrengthMinimum

Grade (ksi) MPa (ksi) MPa

33 33 230 45 31037 37 255 52 36040 40 275 55 38050A 50 345 65 45050 B 50 34580 80 550 82 570

Elongationin 50 mm (2")

Minimum %

2018161212

c. In-line tension leveler provides unsurpassed

uniform flatness for.better appearance in yourfinished products.

d. Operators' console includes a microprocessor-based controller to regulate the new tension leveler.

e. Galvalume coil, ready for shipping.

3

71

Page 3: GALVALUME Sheet Carbon Steel Specs

Corrosion resistance

USS Galvalume's unique coating compo-sition of aluminum and zinc offers superiorcorrosion resistance.

Long -term durabilityThe aluminum causes the Galvalumecoating to behave somewhat like analuminum coated steel in that it helps toform an insoluble oxide film on the surfaceof the coating. This film shields both thecoating and the steel from water and air.In this way it provides not only long-termprotection of the steel but also protectionagainst excessive corrosion of the coatingitself.

Surface protectionUnless otherwise specified, USSGalvalume sheet is chemically treated(passivated) and oiled with a vanishingoil to prevent the formation of storagestains. When properly passivated,USS Galvalume sheet is significantlymore resistant to storage staining thangalvanized sheet.

4

Cut edge protection

The zinc causes the Galvalume coatingto behave somewhat like a zinc (galvan-ized) coating. On exposure to water ormoisture, the zinc in the Galvalumecoating enters into an electrochemicalreaction with exposed steel at a cut edge,crack or other break in the coating. Thisreaction is the critical feature that inhibitscorrosion of exposed steel.

Best all-aroundcorrosion protectionThe result is long-term performance. USSoffers its customers a limited 20-year,6-month warranty against rupture, perfora-tion or structural failure due to corrosionwhen Galvalume sheet is used in roofingor siding applications, exposed to normalatmospheric conditions.

USS Galvalume sheet's combinedprotection of aluminum and zinc has beenshown to provide a minimum of twice thecorrosion resistance-in most atmosphericenvironments-and as much as four timesin some environments than galvanizedsteel having the same coating thickness.

This superior performance has beendemonstrated by exposure tests con-ducted in a wide range of environments,as shown in the chart below.

Atmospheric corrosion losses of Galvalume steeland galvanized steel after 13 years ' exposure 30°to horizontal (average top and bottom surface).

Coating Loss (µm)

25.0

22.5

2.5

0(Severe Marine) (Marine)

Edge appearance of coated sheets after 13-y

Galvanized (G90)

Galvanized(G90)

(Industrial)

Galvalume(AZ50)

(Rural)

ear industrial exposure.

Galvalume (AZ55)

Page 4: GALVALUME Sheet Carbon Steel Specs

Prepainted GALVALUME SHEET

USS Prepainted Galvalume combines asuperior paint system with the excep-tional corrosion resistance of thealuminum -zinc alloy coating. Thecombination provides a prepaintedsheet product that has long -term dura-bility not previously attainable. Thisnew standard of durability is the basisfor the USS 20 -year , 6-month limitedwarranty against substrate perforationfor Prepainted Galvalume.

USS Prepainted Galvalume sheet hasthe same range of attractive colors andfinishes as other coated steel products.For Prepainted Galvalume, the two-coatpaint system includes primers formulatedspecifically for Galvalume to minimizeedge creep and improve adhesion of thetop coat paint film. In addition, USSPrepainted Galvalume receives a chromatepretreatment on the coil-coating line to

further improve corrosion resistance.These steps along with rigorously con-trolled processing practices and qualitycontrol on the coil paint lines result in ahigh-performance prepainted steel sheet.

Today's Prepainted Galvalume andprepainted galvanized sheet exhibit com-parable rates of edge creep on the basisof accelerated corrosion tests and severalyears atmospheric exposure.

5

Experience shows that PrepaintedGalvalume offers distinct advantagesover prepainted galvanized steel:• Better overall paint adhesion during roll

forming.• Less crazing of the paint at bends, thus

reducing the amount of direct contactof the aluminum-zinc coating and steelwith corrosive media.

• Less chance of storage staining at jobsites.

• Improved corrosion protection at paint-damaged areas.

These advantages-combined with theimproved paint systems and processingdevelopments-make new PrepaintedGalvalume an outstanding product formetal buildings.

Page 5: GALVALUME Sheet Carbon Steel Specs

GALVALUME SHEET...

Compatibility withother materialsMost of the fabrication and buildingmaterials used with galvanized steelcan be used with Galvalume steel.

Avoid lead and copper. These twometals will react with Galvalume as theydo with galvanized sheet and can resultin accelerated corrosion of the coatingwherever contact is made. Avoid use oflead-such as lead nails, lead washersand lead flashing. Contact with copperand water runoff from copper flashingalso should be avoided.

High temperatureperformanceHeat resistance-Galvalume sheetserves as a cost-saving substitute foraluminum-coated Type I sheet in inter-mediate temperature applications. Whenused at tempera-tures up to 600°F,Galvalume does notdiscolor under con-tinuous or intermit-tent exposure duringprolonged periods.In some applications,Galvalume performs well at substantiallyhigher temperatures. A special grade-Galvalume HT-is available for appli-cations such as heat shields and gasburner grills.

Heat reflectivity -Galvalume sheet hasexcellent heat reflectivity at temperaturesup to 600°F-equal to that of aluminumcoated Type II sheet.

FormabilityFor many applications, Galvalume steelsheet can be formed as readily asthe comparable grade (CQ, LFQ, SQ, etc.)of continuously annealed galvanizedsheet. For applications that require veryhigh levels of formability, special annealingpractices have been developed.

Roll forming-Galvalume can be readilyroll formed... and many processors rou-tinely roll-form products (such as roofingand siding panels) that include a numberof relatively small diameter bend radii.

Proper lubrication prevents the coatingfrom burnishing and picking up on theforming rolls. Solvent-based lubricants,which leave no oil residue, can be used.Water soluble lubri-cants are satisfactoryonly if the material isallowed to dry beforestacking to avoidstorage stain. Con-tact your lubricantoil manufacturer to

develop proper lubrication methods foryour operation.

To provide for effective lubricationwhen the product is ordered dry (no oil),it is recommended that the lubricant beapplied with felt pads to both surfaces ordirectly applied onto the forming rollsbefore the material enters the formingrolls. It is also suggested that chromium-plated rolls be used to protect the coatingfrom burnishing and scratching.

Vanishing oils are recommended forroll forming because they dry quicklywithout leaving a slippery surface.

Bending -Laboratory tests show goodadherence of the aluminum-zinc coatingto the steel substrate during bendingoperations. As with galvanized, somecrazing of the coating may occur on theoutside of a 180° bend. The Galvalumecoating is susceptible to flaking undervery severe bending, depending on thethickness of the steeland coating. Flakingat reverse bendscan be eliminatedin many cases byincreasing the radiusof the die.

Drawing -A Drawing Quality grade isnot available at present: therefore, deepdraws with Galvalume sheet are notrecommended. However, somedraws can be achieved with specialprocessing during production. Pleasecheck your specific requirement with aUSS Metallurgical Service Representative.

Stretching-Tests show that Galvalumesteel maintains coating adhesion whenstretched to the pointwhere the steelsubstrate fractures.However, somecrazing may occuron severe stretchingapplications.

FasteningA wide range of fastening techniques,similar to those used for galvanized, can beused for Galvalume steel:

Welding -Galvalume sheet is readilyweldable using conventional resistanceand arc welding processes.

6

Resistance Welding (Spot & Seam)Because the aluminum-zinc coating onthe sheet surface affects the flow ofelectric current, resistance welding ofGalvalume steel requires welding currents,welding times and electrode forces higherthan those for simi-lar thicknesses ofuncoated cold rolledsteel. These weldingparameters are simi-lar to those normallyused on galvanizedsteel. However,experience has shown that the weldingparameters for resistance weldingGalvalume are somewhat more restrictive.

Soldering-We do not recommend thesoldering of Galvalume steel. Likealuminum-coated steel, Galvalume steelis more difficult to solder than galvanizedbecause of the aluminum oxide on thesheet's surface and the high solderingtemperatures required for the flux toremove the oxide. Instead, the recom-mended practice is to use fasteners andsealants.

Mechanical fasteners-Fasteners shouldbe selected on the basis of compatibilitywith Galvalume steel to ensure best overallperformance of the building system. Thelife expectancy of the fasteners should beselected to match the life expectancy ofthe Galvalume steel roof.

Rivets and other fasteners containinglead or copper must never be usedin conjunction with Galvalume steelbecause they seri-ously reduce thecorrosion resistanceof the Galvalumecoating. For moreinformation, consulta fastener manufac-turer or contact ourMetallurgical Service Department.

Sealants-A neutral cure silicone rubbersealant is recommended for forming ofwatertight joints. This material needs noprimer. It's flexible and non-corrosive, aswell as resistant to heat, cold, water andultra-violet rays. In selecting a siliconerubber sealant, care should be taken toavoid those with acetic acid or amines,which can promote corrosion during earlystages of curing.

Other types of sealants, such as butylrubber and styrene butadiene rubber, mayalso be considered for certain applications.For more information, consult a sealantmanufacturer or contact our MetallurgicalService Department.

I

Page 6: GALVALUME Sheet Carbon Steel Specs

Size range (in.)

Thickness: 0.015 to 0.052

Width: 24 to 48

Coating composition

Constituent ^

0 byweight

(nominal)

% byvolume(approximate)

Aluminum 55 80%

Zinc 43.4 19%

Silicon 1.6 1%

Coating weight and thickness

• AZ55-Unpainted metal buildingapplications

• AZ50-Prepainted metal building andnon-building applications (AZ55 may beused for non-building applications ifrequested by customer)

The AZ50 coating has a nominalthickness of 0.8 mil (one side) which isequivalent to the thickness of a G90galvanized coating.

Surface Types

Regular (small spangle)Extra smooth (matte finish)

Steel sheet qualities

CQ (Commercial Quality)LFQ (Lock Forming Quality)SQ (Physical Quality-Yield minimums

from 33 ksi to 80 ksi)

A D U S S-30-8676-01

Printed in U.S.A.

February, 1987

USS is a registered trademark

Typical Physical Properties-Commercial Quality Galvalume Sheet

Yield Point (ksi) 38-53

Tensile Strength (ksi) 50-65

Elongation (% in 2 inches) 20/36

Hardness (HRB) 50/65

Corrosion perform-ance of Galvalumeand galvanized 0 6coated steels in

,

rural atmosphere(Saylorsburg Pa.) 737E o, .

LUcnCz 0.40

00:3

100wC7 02

GALVANIZED L'iSHEET < 0 .

GALVALUME

0SHEET0 2 4 6 8 10 1 2

E XPOSU RE TIME , YEAR S

Corrosion perform-ance of Galvalumeand galvanized

0 6coated steels ,

in industrialatmosphere 0 5(Bethl h Pe em, a.)

0

0 0A00If

0 3.00w

e 0 2.CEw

Q0 1.

00 2 4 6 8 10 12

E XPOSU RE TIME , YEAR S

Galvalume is a trademark ofBethlehem Steel Corp.