简介:利用扫描电子显微镜、能谱仪、光学显微镜及电子探针等对比分析了Q235B钢板拉伸试验后出现分层和不分层的两组试样,研究引起钢板拉伸分层的原因。试验结果表明:分层试样中心含有大量的MnS、Si02等夹杂,心部存在宽大的铁素体条带,是导致Q235B铜板出现拉伸分层现象的主要原因。根据分析结果提出改进措施以减少和消除此种缺陷。
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
简介:Basedontheeffectsofseveralcastingparametersonslagentrapmentinthemould(watermodeling),thenumericalmodelingwasresearched.Theresultsshowthattheflowfieldwithasubmergednozzlesectiondimensionof65mm×80mmisbetterthanthatwithasubmergednozzlesectiondimensionof40mm×40mmandisfavorableforavoidingslagentrapment.Inthispaper,lowsurfacevelocity,smalllevelfluctuationandproperimpactdepthcanbeachievedwithanozzleofanoutletangleof25°andanimmersiondepthof150mm,orwithaprototypenozzleofanoutletangleof15°angleandanimmersiondepthof150mm.
简介:Themorphologyandtheevolutionofδ-ferriteexistinginB410Dslabs,hot-rolledplates,annealedplatesandquenchedplateswerestudiedthroughmetallographicobservation.Resultsshowthatδ-ferriteformsduringthesolidificationprocessandthatiteasilygrowsandincreasesinquantityduringhightemperatureannealing.Band-shapedδ-ferriteinhotrolledplatesisdifficulttobeeliminatedbyconventionalheattreatmentandhardtorecrystallize.
简介:Thedull-finishferriticstainlesssteel(FSS)sheetB445RforarchitecturalroofinghasbeendevelopedbyBaosteel.ThissteelproductexhibitsexcellentcorrosionresistancesuperiortothatofSUS316Lwithalowercost.Itcanbeeasilyformedintoroofingpanelsbyordinaryprocesses.Moreover,thethermalstrainofitislessthanSUS316Lbecauseofitslowerthermalexpansioncoefficient,anditsreflectivityislowerduetothedull-finishtreatment.Allofthesefeaturesmakeitcapableofbeingusedasarchitecturalroofingmaterialsincoastalregions.
简介:采用金相显微分析和电镜及能谱分析方法对延伸率不合格的Q235B热轧普板进行非金属夹杂物、金相组织分析。分析结果认为Q235B热轧普板延伸率不合格是由于钢板中心存在大量的条带状MnS夹杂所致。并根据分析结果,提出提高冶炼质量,控制钢水中的硫和杂质元素的含量,对提高延伸性能十分重要的观点。
简介:ThemicrostructuralchangesofFe83Si4B13amorphousmotheralloyduringtheheatingprocesswereinvestigatedbyLaserScanningConfocalMicroscopy(LSCM),andthephasetransformationwasdeterminedbytheThermo-Calccalculations.ThedifferencesinthemeltingpointsmeasuredbyDifferentialScanningCalorimetry(DSC)andLSCM,andthoseobtainedbyThermo-Calccalculationswerealsodiscussed.ItisfoundthatthemeltingpointsmeasuredbyDSCandLSCMarerelativelysimilar,whereastheonsetandendofthemeltingtemperaturescalculatedbyThermo-CalcsoftwarearehigherthanthosemeasuredbyDSCandobservedbyLSCM.
简介:我国焦炭产量在2006年达到29768万吨,占全球总量的57%,成为世界最大的生产、消费和出口国。炼焦生产每年消费炼焦煤4亿多吨,耗费原煤量高达7~8亿吨,是名副其实的耗能"大户"。去年以来,在国家相关部委的推动下,全国累计淘汰落后焦炭产能1500多万吨,但焦化行业重复建设、盲