Comments on the report of the Study Group SG-212 “The Physics of Welding” at the 70th IIW Annual Assembly and International Conference

The IIW Study Group 212（Physics of Welding）Documents presented at the 70^th Annual Assembly of International Institute of Welding,25-30 June 2017,Shanghai,were reviewed.Based on some representative papers from home and abroad,the most recent investigation results on the arc physics,metal transfer,weld pool behaviors,metal vapor,fume emission,etc.were introduced.Some issues which should be focused on next step were pointed out.