材料成型及控制工程专业英语配套教学课件刘瑛电子课件 Unit 17.ppt

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1、Unit17Weldingprocesses焊接工艺Objective3.2.4.1.Knowtheclassificationsofwelding;Befamiliarwiththetwomaintypesofarcwelding;Makeclassificationsofsubclasses.Understandthebasicpartsofarcwelding;WarmingupReadthefollowinginstructionabouttheclassificationsofwelding.Fill

2、inthetableinFig.17-1fromthegivenchoices.Thechoicesare:(a)MIGWelding(b)FusionWelding(c)TIGWelding(d)ForgeWeldingTask1(1)b(2)d(3)a(4)cAnswerTextWatchVideo17-1,andfillintheblanksaccordingtowhatyou’veheard.Task2(1)meltingpoints(2)weldingmachine(3)fillermetal(4)e

3、lectricarc(5)weldingwire(6)stickelectrodes(7)solidwire(8)fluxcoredwire(药芯焊丝)(9)stickelectrodes(10)gascylinder(11)chemicalAnswerTextWatchVideo17-1again,andanswerthefollowingquestions.(1)Whatarethethreepartsofweldingprocess?(2)Whatarethetwobasictypesoffillerme

4、tal?(3)Whatarethetwowaysofdeliveringshieldinggas?Andinwhatkindofsituationaretheyused?Task3(1)Therearethreepartsoftheweldingprocess:theweldingarc,thefillermetal,andshieldingtheweld.(2)Therearetwobasictypesoffillermetalsusedinwelding:weldingwireandstickelectro

5、des.(3)Shieldinggasisdeliveredtotheweldingareainoneoftwoways:Thefirstwayisfromagascylinder.Thisisthestandardmethodwhensolid,orbarewire,isused.Thesecondwayisfromaspecialchemicalthathasbeenaddedtothefillermetal.Allstickelectrodesandfluxcoredwireareusedwithouta

6、gascylinder.AnswerTextWatchVideo17-2.Accordingtoyourunderstandingofthetwocommontypesofarcwelding,writedowntheirnamesintheFigure.Task4(1)wirefeedwelding(2)stickweldingAnswer(1)………………….(2)………………….TextCheckthefollowingdescriptions.Ifthesentenceiscorrect,justtic

7、kit(√).Ifthesentenceisincorrect,fixit.(1)Wirefeedweldingdoesnotuseaguntofeedthewireintotheweldingarea.(2)Whenfluxcoredwireisused,shieldinggasfromagascylinderconnectedtothemachineisneededtoprotecttheweld.(3)Stickweldingdoesnotuseagun.(4)Additionalshieldinggas

8、isusedinstickwelding.Task5(1)Wirefeedweldingusesaguntofeedthewireintotheweldingarea.(2)Whensolidwireisused,shieldinggasfromagascylinderconnectedtothemachineisneededtoprotecttheweld.(3)√(4)Noaddi