简介：Traditionally,austeniticstainlesssteels304and316havebeenemployedincoastalregionsasroofingmaterialsunfortunately,theyareexpensiveandnotfullyresistanttopittingcorrosionunderseverecoastalcorrosiveenvironment.AferriticstainlesssteelB445Rwasdeveloped.Comparedwithaustenitic316L,B445Ris①lesscostly;②uperiorcorrosionresistantwithminormaintenanceforlong-termservice;③insusceptibletothermaldistortionintheweldingseam.B445Rsheetshowsahigheryieldstrengthandlowertensilestrength,lowerelongationandlowerwork-hardeningthanaustenitic316L.Itcanbeeasilyfabricatedanddeformedjustlikeplaincarbonsteel.Afterbending180o,thereisnooccurrenceof'cracking'ornoticeable'orangepeel'.Theformabilityoftheweldingseamisalsosatisfactory.ThepittingpotentialofB445Ris650mV,largerthanthatof304and316L,asshowninFig.1.ThecorrosionrateofB445Rsubmergedin6%FeCl,solutionis0.3-0.56g/(m2?h-1),muchlowerthanthatof316L,asshowninFig.2.ThesuperiorpittingcorrosionresistanceofB445RcanbeascribedtosynergeticeffectofhigherCrandMo.Dull-finishedB445RsheetshavebeenemployedastheroofingmaterialsforGuangzhouAsianGamesArena,asshowninFig.3.About380tof1.0mmB445Rwithdullfinishwasusedforroofingpanels.About100tof0.8mmB445Rwithhairlineorfluororesinpaintfinishwasusedforsidewallpanels.Thecompositeroofbuild-up（fromuptobottom）includes:①shinglesofferriticstainlesssteelB445R;②Kalzip-typestandingseamofaustenitic304;③water-proofDFM;④structuralsteel;⑤75mmthickinsulation;⑥secondarypurlinof150mm×100mm×4.5mmofgalvaniziedQ235;⑦0.8mmthickprofiledeckofgalvaniziedQ235;⑧acousticinsulation.Theroofingshinglesorpanelswiththesamewidthbutdifferentlengthwereformedbybendingfoursidesandfixedtoa'L'shapereinforcingframesofstainlesssteelbyfasteners.The'L'frameswasconnectedtoribsofthestandingseambyacl