This study analyzed and discussed the vacuum electron beam welding (EBW) process of 30CrMnSiNi2A ultra-high strength steel in bottom-lock welding form. The microstructure and mechanical properties of the welded joint are studied by metallographic analysis

microhardness and scanning electron microscope (SEM)

and analyzes the common defects and preventing methods in welding. The results show that under the appropriate EBW parameters

30CrMnSiNi2A steel can achieve good weld appearance with better comprehensive mechanical properties

by X-ray and magnetic powder flaw detection

the weld bead meet the requirements of class I weld

and this EBW welding procedure is successfully applied to the airframe products.