铝MIG焊接工艺

BlackdepositonandbesidestheweldWithmanyapplications(palletsforthechemicalandfoodindustry,ladders,scaffoldings)theblackdepositisratherdisturbing.Simplebrushingremovesit,however,requiresadditionaloperationswhichcanoftenbedoneonlymanuallyatareasoflimitedaccess.ThedepositresultsfromevaporationandfollowingfalloutofMagnesiumoxide.MagnesiumisanalloyingelementofAluminiumwhichsubstantiallyincreasesitsstrengthandcannotbeleftoutinmostcases.Magnesiumoxideisusuallyknownwithwhitecolour.AnEDS-analysiseliminateseverydoubtofnotbeingMgOwhichisknowntoshowcoloursofgrey,yellow,brownorblackbesidesitswhiteformofexistence.ThefollowingpossibilitiesexisttopreventMgO-formation:UseofwireelectrodeswithlowornoMgcontent(AlMg3,AlSi5)OptimisedpulseparametersforthelowestpossibleformationofmetalvapourAvoidpooraccessibilityandresultingunfavourabletorchpositionSufficientshielding-gasprotectiontokeeptheintakeofOxygenaslowaspossible