To　resist　the　alternating　electromagnetic　loads,　the　International　Thermonuclear　Experimental　Reactor　(ITER)　correction　coils　are　protected　by　a　20-mm-thick　316LN　austenitic　stainless　steel　case.　According　to　the　strict　tolerance　requirement　of　the　case　manufacture,　laser　welding　was　applied　to　enclosure　welding　of　the　cases　with　a　20-kW　high-power　laser　for　root　pass　and　Tungsten　Inert　Gas　welding　was　applied　for　filler　and　cover　passes.　In　this　study,　the　microstructure　and　mechanical　properties　of　enclosure　welding　joint　were　investigated　to　evaluate　the　quality　of　the　joints.　No　porosity,　crack　or　lack　of　fusion　was　found　on　the　cross-section　of　the　joints.　The　microstructure　in　the　weld　zone　is　single　austenite　phase　and　the　morphology　of　the　joint　consists　of　cellular　crystal,　columnar　crystal,　and　small　amount　of　the　equiaxed　grain.　The　average　tensile　strength　of　the　joint　is　590　MPa,　which　is　98.3　&　x0025;　of　the　strength　of　the　base　material　of　600　MPa.　The　fracture　position　is　located　at　the　base　material　with　an　apparent　necking　morphology,　which　confirmed　the　good　plasticity.　The　side　bend　test　specimens　were　subjected　to　significant　plastic　deformation,　which　bent　through　180　&　x00B0;　and　no　surface　crack　can　be　found.　The　impact　toughness　of　the　weld　joint　at　4.2　K　is　larger　than　180　J　&　x002F;cm(2),　and　the　fracture　surface　is　composed　of　fine　equiaxed　dimples　and　tearing　ridges,　which　indicates　that　the　specimens　failed　in　a　ductile　manner.　All　of　the　test　results　satisfy　the　ITER　requirements.