Introducing　the　aluminum　alloy　into　the　steel　body　structure　allows　the　reduction　in　the　vehicle　weight　and　improves　the　fuel　efficiency.　However,　it　is　a　still　great　challenge　to　weld　aluminum　alloy　to　steel　due　to　their　differences　in　the　physical,　mechanical　and　metallurgical　properties.　In　this　study,　aluminum　alloy　6061-T6　was　welded　with　zinc　coated　low　carbon　steel　by　cold　metal　transfer　(CMT).　Effects　of　the　pre-setting　gap　at　the　interface　of　aluminum　alloy　sheet　and　steel　sheet　as　well　as　the　offset　distance　of　the　electrode　torch　from　the　aluminum　alloy　sheet　edge　on　the　weld　qualities　were　investigated.　The　tensile　shear　tests　were　carried　out　to　evaluate　the　mechanical　property　of　the　welds.　In　addition,　optical　micrograph,　scanning　electron　microscope　(SEM)　and　Energy　Dispersive　Spectrometer　(EDS)　were　used　to　analyze　the　weld　microstructure.　Experimental　results　indicated　that　the　intermetallic　layer　thickness　in　the　CMT　welds　was　well　controlled　below　the　10　mu　m,　which　facilitates　the　achievement　of　relatively　high　weld　strength.　Furthermore,　a　pre-setting　gap　and　an　appropriate　post-weld　heat　treatment　can　improve　the　weld　strength.　However,　the　weld　strength　was　decreased　by　increasing　the　offset　distance　of　arc　torch.　In　addition,　the　pre-setting　gap　also　affects　the　intermetallic　layer　morphology.　The　formation　of　brittle　AlxFey　could　be　suppressed　by　the　presence　of　the　remained　zinc　in　the　steel　side.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.