az31镁合金钨极交流氩弧焊工艺的研究

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1、AZ31镁食金钨擐交濂氩弧焊置芑匏磺巍摘要本文瓣厚度为l+2ramAZ31镁台鑫薄板的钨檄交流手工氨弧焊(GTAW)王莲遘毒予了磷究，努爨了套耱溽谈嚣索(浮搂毫滚、季孝辩麓表瑟狻态、绦护气体流璧、有茺辫丝、浑后热娥璞等)对焊缝成型和焊接质量的影响及其规露。涮蔫龛程显徽链、X辫线嵇=鸯雩铰、万戆控锌试验税彝{薯撼毫予显檄镜等技术漪弹按接头艇微组织、焊缝棚组成、接头力学性能、麟口形貔特征以及撇溪或分镣进褥了努援；势对爝接过程中气我秘裂纹产生貔爨霆秘耱止撩蕤进行了讨论。试验绉果襄鞠，AZ31镁台鑫氯孤挥靖，焊接工慧条箨对拜缝袭瑟形状帮烊缝成篷质量脊徽大影响。镁食金材料表璇存在氧化膜时+

2、焊接熄深浅，熔塞大；撵缝静薅爨帮薅深隧辫接鬯滚嬲臻太褥灌大；撵缝豹熔宽疆保势气髂流蠛的增大先加巅、艨变窄，焊接熔深髓保护气体流量的增大先增大、艏减套。采弱会遥黪辫接王装麓褥爨努鬟戏鍪受好，凑嚣无气程窝簧绞熬烽搂接头。AZ3l镁会叠氢甄辫接头豁燕澎螭医稿辫缝势眷甥显，熟嚣豌蘸鑫粒较糕犬，弹缝为细小的等轴艇，焊缝主要存在攫一Mg葺眭§*Mgj47AIl2掰料裙。镶律群隧彤羲分撰交鞠，浑接接头塞耱牲～鼹毪滋会簌裂，灏袈一般发垒燕熬狡较糨大的热影响愿。与蹲糕耀比，AZ3l镁含金焊缝中镁禽量有所降低，锻会壤青掰壤大。浮接电流对AZ31镁含垒薄扳氲弧焊的接头力举性能影噙锻大，电流太大或者太夺

3、，帮会篌接头懿鸯擘经箍泽舔。不捷爝填充浑旋，当焊接邀瀛惫45A、钨钟宜径为l。6ram、保护气体流量先15L／rain时，AZ31镁念余薄板氟薮褥接头浆力攀髅旋可遮舞母耪戆79％庭蠢。添擞溪充浮簸爨爨糍AZ3t镁会◇接头瓣力学性能，烽蜃经热处毽阿进一掺改善接头的缀级性艟。AZ3l镬会袅氧弧辫接头审气乳酌形成鞭困主鼗是冷却过程审塞子氯在镁中的溶勰度急蒯下降姆致氢大量蛎出露形成氢气扎，其次是镁仓金中低熔熹会金元繁蒸发麓损嚣形成静气藐。AZ3l镁合金氨弧海撩头孛热裘绞酌产生燕要与镁会金中存在低熔点凝赫体裔失。关键谗：镁金会；羲溅烽；缆绞性簸；气薤；凝绞AbstractInthisthe

4、sis，theinfluenceofweldingfactors(weldingcurrent，surfacecoatingandoxidefilm，shieldinggas，weldingwire，postweldheattreatment)ongeometryandqualityofweldedjointsofgastungstenarc(GTAW)weldedmagnesiumalloyAZ31plateswith1．2thicknesswasdiscussed．Themicrostructurewasinvestigatedwithopticalmicroscopy．Me

5、chanicalpropertiesweredeterminedbystandardtensiletestsonsmall-scalespecimens．Fractographycharacteristicswereobservedbyscanningelectronmicroscopy(SEM)．Meanwhile，thefactorsleadingtotheformingofporosityandcrackinginweldedjointswereanalyzedandthemethodstoavoidporosityandcrackingweredescribed．Ther

6、esultindicatedthatweldingparametershavegreatimpactontheshapeandmicrostruetureofthejoints．Whenoxidefilmonthesurfaceofmagnesiumalloyisnoterased，theweldiswideandshallow．Thewidthandpenetrationofweldincreasesastheweldingcurrentincreasing．Theweldbroadensfirstly，thennarrowsastheshieldinggasincreasin

7、g，andthesameisthepenetration．Whentheweldingparametersarefeasible，itcangetwellweldformation，noporosityandcrackingexistsintheweldedjoints．Themicrostructureisfineequiaxedgrainsinweldedzone．whichisshowntoconsistofⅡ-MgandMgI7A112．whilethemicrostru