简介：Mostoftheinvestigationsregardingfrictionstirwelding(FSW)ofaluminumalloyplateshavebeenlimitedtoabout5to6mmthickplates.InpriorworkconductedthevariousaspectsconcerningtheprocessparametersandtheFSWtoolgeometrywerestudiedutilizingfrictionstirweldingof12mmthickcommercialgradealuminumalloy.Twodifferentsimple-tomanufacturetoolgeometrieswereused.TheeffectofvaryingweldingparametersanddwelltimeofFSWtoolonmechanicalpropertiesandweldqualitywasexamined.Itwasobservedthatinordertoachieveadefectfreeweldingonsuchthickaluminumalloyplates,toolhavingtrapezoidalpingeometrywassuitable.Adequatetensilestrengthandductilitycanbeachievedutilizingacombinationofhightoolrotationalspeedofabout2000r/minandlowspeedofweldingaround28mm/min.Atverylowandhighdwelltimetheductilityofweldedjointsarereducedsignificantly.

简介：由于船舶自身价值高、设备多,一艘运砂船少则2人,多则十多人,运砂船沉没事故的发生,不仅直接经济损失巨大,而且对家庭和睦、幸福及社会稳定产生较大影响。文章通过对宁波港历年运砂船装砂作业期间沉没事故有关情况的统计,分析影响装砂作业安全的因素,提出防范该类事故发生的管理措施和对策。