RostfreiMakeZincalumeSteelSilos

“TheFutureofGrainSiloIndustry”Authoredby:PKBhardwaj

Rostfrei Steels Pvt. Ltd. is India’s one of the most renowned and trustedManufacturers, Exporters and Suppliers ofBulk Storage Silos for Solids andLiquids.Sincelast17years,Rostfreihascompletedmorethan8000installationsworldwideinapprox.25countries.

Rostfrei SteelsPvtLtd. products arevalue formoney, long lasting andwellengineered.

HowRostfreimakesilosaredifferentfromsilosmadebyotherGrainSiloSuppliers?

Rostfreimake silos aremore suitable for tropical and sub-tropical regions likeIndiaastheyaremadeofZincalumeSteelandColorbondSteel.ZincalumesteelandColorbondSteelSilosperformsfarbetterthanconventionalGISteelsilosinIndialikeclimates.InColorbondSteelonecanchooseanycolortomatchexistingcolorthemeofcustomer’sfactory.

Figure1:300MTPaddySilosinSonepat

WhatisRostfreimakeZincalumeSteelandhowitisdifferentfromGISteel?

GrainSilosarefabricatedinfollowingfourMetalCoatedSteels

• GISteel-99.7%Zinc+0.2%AluminumCoating

• Galfan-95%Zinc+5%AluminumCoating

• Magnelis-93.5%Zinc+3.5%Aluminum+3%ManganeseCoating,and

• Zincalume-43.5%Zinc+55%Aluminum+1.5%SiliconCoatingGalfan, Magnelis and Zincalume all perform better than GI Steel as they arebettermaterialsforlongtermstorageofgrainsinSilo.ZINCALUMESteelhasAlloycoatingof55%aluminium,43.4%zincand1.6%silicon which is carried out at 600 Deg C, hence more uniform and strong.Zincalume is the best material for long-term storage of grains as it hasexcellentThermal Reflectivity, Corrosion Resistant, Lightweight andStrongerthanconventionalGalvanisedsteelmaterial.

WhataretheproblemsassociatedwithGISteelSilos?ThebiggestproblemisthattheaverageservicelifeofGISteelSilosisveryless.GISteelhavemetalcoatingof99.7%Zincovermildsteelwhichiscarriedoutat450DegC.ZincCoatingsavesmildsteelfromgettingcorroded.Zincreactswithatmospheric oxygen in the presence of humidity and form Zinc Oxide. Zincprotects basemetalmild steel by sacrificing itself,whichmeans by convertingitself to Zinc Oxide. Eventuallywith the passage of timewhole of zinc coatinggetssacrificedandbasemetalmildsteel isexposedandthereaftercorrosion isveryfast.Since zinc reactswith atmosphericoxygenonly in thepresenceofhumidity intheair. Wherever thehumidity ismore the reaction is fast andwherever it isless reaction is slow. Warmer air has more capability to hold moisture andcolderairhaslesscapabilitytoholdmoisture.HenceGIperformsbetterincolderclimates than inwarmer climates hencemore popular in countrieswhere theclimaticiscoldmostofthetime.

In tropical and sub-tropical regions since the air is very humid, GI does notperformtoitsexpectations.

AverageServiceLifeofofGISteelsilosisasmentionedinthetablebelow;

GI Std. G40 G60 G90 G115 G140 G165 G210 Oz/ft2 0.4 0.6 0.9 1.15 1.4 1.65 2.1 g/m2 122 183 275 351 427 504 641

Service Life 7-9 Yrs 10-12

Yrs 15-18 Yrs

20-23 Yrs

24-27 Yrs

28-32 Yrs

36-41 Yrs

Note:-IndianClimatefallbetweenTemperateMarineandTropicalMarine

HowRostfreiMakeZincalumesolvesthecorrosionproblems

ZINCALUMESteelhasAlloycoatingof55%aluminium,43.4%zincand1.6%silicon by weight. Since Aluminium is a lightermetal hence volumetrically itoccupies approximately 80% of the volume, and hence aluminium helps toprotect zinc coming in contact with atmospheric humidity and oxygen. Thus,Zincalume has double protection - Barrier protection of Aluminium andGalvanicprotectionofZinc. AluminiumisprotectingZincandZincisfurtherprotectingBasemetal.

G115

WhatareadvantagesofRostfreiMakeZincalumeSteelSilos?Zincalume Steel Silos provide following benefits that no other grain silo canprovidesoefficiently

• Uniform Alloy Coating: ZINCALUME Steel has Alloy coating of 55%aluminium,43.4% zinc and1.6% siliconwhich is carried out at 600DegC,hencemoreuniformandstrong.

• Durability:ZincalumesteelhasverygoodCorrosionResistantPropertiesandcanwithstandSaltSprayTestof2000hourswhereasGI350GSMcanwithstandasaltspraytestofonly500hours.

• ExcellentThermalReflectivity:RostfreiMakeZincalumeSteelSiloshasExcellent Thermal Reflectivity of Solar Heat to reduce Heat Radiationsinside. Hence Zincalume absorb only 4-5%heat as against GI Silos thatabsorb 22% to 26% heat, hence grains in Zincalume Silos areapproximately4DegCoolerthanGISilos

• Scratch Resistant: Rostfrei Make ZINCALUME steel is coated withspeciallydevelopedpassivationandresincoatingasseparatelayersthatimproves its scratch resistance qualities. Hence Zincalume looks newerforlongmaintainingitslustre

• Last Lasting Lustre: Special treatment provided to Zincalume Steelreduces the rateofoxidationand resultantdiscoloration (Darkening)ofZincalumesteelshencelooknewerforlongertime.GISteelsilosbecomedullgreyincolorwithin2yearsofoperationandstartabsorbing26%ofsolarheat,whichdamagesgrains.

• ServiceLife:ZINCALUMESilosprovidesupto3to4timestheservicelifeof Galvanised steel silos of same coating thickness. Average Life ofZincalumeSiloisapproximately40-50yearsasagainst15to18yearsofGalvanisedsteelsiloshavingsamecoatingthickness

• Warranty: Only Rostfrei make ZINCALUME steel comes with up to 20years warranty against perforation by weathering from the date ofinstallationinneutralenvironment

Figure2-MaizeSilo5000MTinTamilnadu

HowRostfreiMakeZincalumeSteelSilosarebestforGrainslikePaddy?RostfreimakeZincalumesteelssilosarenotonlygoodforPaddybutforallthegrains.HoweverinPaddytheygivebestperformancethananyothertypeofsilo.Therearemanyreasonsforthisandsomeofthemare;

¡ CoolerGrains:SinceZincalumeSteelabsorbonly4-5%heatasagainstGISilosthatabsorb22%to26%heat,hencegrainsinZincalumeSilosareatleast 4 Deg Cooler than GI Silos. Moreover it helps grains maintain itsmoisturelevelsanddoesnotresultweightlossdueinmoistureloss.

¡ Power Savings: Cooler Grains requires lesser aeration and lesserinfestationproblemsthusgivemoresavingsonpowercostandfumigantcost

¡ DiscolorationofGrains:Highsolarheatabsorptionbygrainsincreasesaverage temperature inside silos,which results inbrowning,blackeningordiscolorationofgrains.

¡ LesserBrokens:Moreoverhighsolarheatabsorption inGISilosmakesgrainsmorebrittleandwhichultimatelybreaksduringdryingormillingofgrains,resultinginmoreBrokens.

¡ HighMoistureStorability:ZincalumeSteelismuchbettersteeltostoreGrainwith highmoisture content as it is tested towithstand salt spraytest of 2000 Hours as against 240 Hours of GI Steels of same coatingthickness.

Whymost other suppliers are not shifting to Zincalume Steel if it has somanyadvantages?

History of Grain Silos is very old. This concept started in 1907 and since thenpeople aremanufacturing grain silos. Since it started in colder places like US,Canada and Europe where humidity problems were less, GI Steel is the mostobvious choice as it was cheap and performing fairly well in those climates.HencetheyprobablyneverfeltaneedtoswitchtorelativelyexpansivematerialslikeZincalume,as95%oftheirmarketisthatareasonly.However,peoplenowunderstand the advantages of Zincalume Steel Silos and eventually shift toZincalumeSteelSilosinnearfuture.

WhatistheUSPofRostfreiMakeZincalumeSteelSilos?InRostfreiwedon’t treatSiloasastaticstoragetank,wetreat itasadynamicmachinewhereinlivegrainscanbekeptandtheirqualitycanbemaintained.Inshort,wefocusmoreonEffectiveGrainManagementinsidesilo.We stress more upon sizing Aeration System properly and balancing it byproviding adequateRoof Ventilation. We provideTemperature MonitoringSystemthatcanwithstandthegrainpressureandaccuratetothe+/-0.5DegC.Thiscanbemonitoredremotely.

WesizetheFumigationSysteminsuchawaythatpressuredropsareminimumandrequirednumbersofairchangesareeffectivelyachievedwithpropersafetyprecautions as Phosphine gas is explosive when its concentration reachmorethan17900ppm.

Figure3:2000MTColorbondPaddySilosinAmritsar