1.Imroductlon CSP-compact strlpproductlon Is an advanced manufac-turing technology,which produces hot strips using a briefproduction line owning science.technology and engineering.The叩amltv ofhot strips Is demanded more and more In thepresent market;which promotes CSP rapid development Onone ban人although CSP sets are wlddy Putm0 use卜eCause01 ILs a口V＆＊Ce口L＊＊＊＊010巨V ＊n口I＊clllU＊8.【0＊V ＊re 口IsM＊＊LIYOth COllV6at1Oll＆l 口TOC6SS“ ill lfigOL CS,ut1Hg、f6ll68t SCfl6Q一ule,rolling process;delivery speed on the runout table and soon.On the other hand;people realize that mlcrostructure andproperties ofultrathln hot strips have ma叮 speclnc character-lstlcs that are In rel毗lonto not onlychemlcalcompone吐s butalso mlsorlentatlon of mlcrostructures.Mentioned as above,the knowledge of Influencing mechanisms about technics,ml-crostructure evolveme皿 and mlsorlemation Is slgnlfica尬 fortheory and product practice. Characteristics ofmlsorle血毗ion and mlcrostructureevolveme尬 ofultrathlnhot strlpwere sole讨lficallystudled。lug electron back-scattered dlffraction（EBSD）analytiCaldevice and Autoforge finite eleme尬 program,which providedfor making out a schedule to improve the properties of theultrathinhot strip.2.Analysis on Microstructure and Misorie尬ation2.1Op枕u而一os（ruccure Specimens were got fromthe ultr础hlnhot strip coil（l.0 mm gauge）produced by CSP technology In ZhlllangSteel Plant;components of which are presented In Table. Mlcrostructures shown In Fig.lwere researched In order tounders〔一d the r幻k北>D SinSuPs am。ng teChDICS,m1Cr08tructweevolution and mechanical properties. The fe毗ure offinal mlcrostructures consisted ofa lot ofpdygonal卜rrltes and some pead亢es.The dlmenslond卜卜rueParhdes——s6Deb吐一tuD沏Im,and劝0以 6.48vmfPr。卜ss。r;加wb。m。。rresp。ndencesh。mdbe。ddressed E-mail:枕ngylln@mater.＂sib.edu.on. Fig.IOptlcal mlcrostructures ofultrathlnhot stripdetermined by LEO-1450 scanning electron microscope In-strument.2.ZAnthe。on EBEBSDSD m。。ostruct。。 Electron back-scattered dl伍actlontechnology as an validmethod to research mlcrostructure Is developing rapidly In reS elteltyeaIS,几——nPI——demoredetaus——dl刊卜ma儿10nthanmetallograPhlc examln毗ion.Direct relationship between ml-crostructures and mlsorle血毗ions o征rs a w沁 to analyze ml-CIO毗rudure ev01u认〕n伽iii止e卯1吐d wew。he扛ure. Ferrite partwtes still kept fine;uniform Characters even吮er吵ne口一协m础I。D加sdm thme。。MItIODdDue;llnlform austenlte particles because oflalcrostructure corn郴raM仙。f咖sc让am缸m讪。n,S卜hh一1吨e＊皿CIO,壮udure aM的ahof加t r。m旭——幻enl加IS S侣DI仇a尬for co尬rol to a phase transform时ion and products prop-enIeS.B％d皿Rg.2,la侣e a吧ie mIS0lle尬毗10D8——re幻111being among ferrlte grains although some允rrlte particles contamed sub以ams,so manyny ofaustenlte particles recrystalllzedduring hot rollingprocess accordingic this.The perce饥明eoflarge angle mlsorle吐毗ions Increasedwlth small allgle mis-502 J.Mater.Set.Technol.;VoL18 No.6,2002 Table Chemical composition of。carbon steel（wt pci） C Mn St P S Cll AI0刀5～0刀7 0.20～0.30 0刀5～0刀7<0刀16<0刀06<0.15<0刀32——。 AOuonbolljoH 一——————一】MisorienationanglohhegFig.2（a）Misorientatlo。angle distribution of＊thebution nit。thin hot strip,（b）microstructure of the ultrathln hot strip based on mlsorle尬毗ion — —W-----------————/x?二 2 4 6 8 10 12 14 Gr由n山ameter/以mFig.3 Distribution ofparticledlmenslons of＊theicledlmenslons ultrathln hot strlplnterms ofmlsorle尬ationone尬atlonsdecreasing becausethe subgralns ownedslmllarmlsorle尬毗ions reducing In the process ofrecrystalllz劝ion.We can concludethat finishingbt rolling mlcrostructureswere a mixture ofrecrystalllzed and deformed austenlte.Theperce尬age ofrecrystalllzedaustenlte was gre毗erthanth眈of deformed austenlte. Most grains profiles were polygon,and not regular.Fer-rltegralns would co尬Inuously growbecause ofnot reachingto stable angle（120 deg.）among grain bound。ies based onmetallograph（Fig.1）and EBsD analytical map（Fig.2）. The distribution ofpartlcle dimensions prese尬lug a peakbr the dimension o且3vm ws similar to厂 distribution,whichmay
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