Study of cold Ironing Aluminum Hollow tubes by Finite Element Analysis

Abstract

[[abstract]]摘要：本研究採用鋁合金AA7050引縮成形的滑動桿作為研究標的，先以Deform軟體針對中空管引縮成形模具的眼模半角、面積縮減率作模擬成形分析，確認製程範圍與可行性，配合使用的胚料管來決定成形道次同時進行模具設計、製作與驗證，再參考載具「登山車避震前叉」的檢驗規範EN14766進行動態疲勞測試。模擬結果顯示單一道次的面積縮減率超過45%將會有成形斷裂以及變形不均的潛在風險，由於使用的胚料管均已超過該面積縮減率為前提下，所以採取二道次引縮成形，眼模半角則分析出低於5?角的製程穩定範圍，再結合眼模高度的限制條件下設計確定眼模半角固定為3?角進行模具製作與成形加工，經過動態疲勞測試後發現：第一道次面積縮減率41.7%配合第二道次面積縮減率13.64%的滑動桿經過動態疲勞壽命平均可達到25.5萬次，優於第一道次面積縮減率20.9%配合第二道次面積縮減率13.64%（疲勞壽命平均僅為8.6萬次）及21.8%（疲勞壽命平均為15.7萬次），順利達成穩定量產平均超過20萬次的目標。關鍵詞：登山車避震前叉、冷間引縮成形、眼模半角、面積縮減率[[abstract]]ABSTRACTThearticlewasinvestigatedofthealuminumalloy7050slidertubemadebycoldIroning,andfirsttothehollowtubeIroningmoldwithsemi-angleandreductionratemakesthesimulationforminganalysisbytheDEFORM,confirmedthesystemregulationscopeandthefeasibility.Followingtheunformedtubedecidedtheformedwhilegoingalongsimultaneouslycarriesonthemolddesign,themanufactureandtheconfirmation,thenreferstothevehicle“MountainBicyclessuspensionfork“examinationstandardEN14766tocarryonthedynamicfatiguetest.TheanalogueresultwillshowthesingletimeIroningofreductionrateover45%willbebreaktheformingprocessandthedeformationofthepotentialrisks,Associatedwiththeuseoftheunformedtubearealreadyoverthereductionrate,thereforewilladopttwotimesIroningtopushthesystemforming;Thesemi-angleanalyzesislowerthan5?anglesthesystemregulationstablescopes,plusthemoldhighlimitingfactorthatdetermineeyemoldsemi-angleisfixedat3?andcarriesonthemoldmanufactureandtheformedprocessing.Afterpassesthroughthedynamicfatiguetesttodiscover:firstmeetingreductionratewith41.7%ofthesecondmeetingofthe13.64%slidertubeisdynamicfatiguelifeaverageof255thousandtimes,betterthanthefirsttimereductionrate20.9%inconjunctionwiththesecondmeetingreductionrate13.64%(fatiguelifeaverageofonly86thousand)and21.8%(fatiguelifeaverageof157thousand),achievestabilityinvolumeproductionaveragedover200thousandtarget.Keywords:MountainBicyclessuspensionfork、coldIroning、eyemoldsemi-angle、reductionrat