Comparative Study of Electron Beam Welding and Shielded Metal Arc Welding of 30CrMnSiNi2A Thick Wall Cylinder

30CrMnSiNi2A ultra-high strength steel is widely used in the manufacture of aerospace structural components. In the aerospace manufacturing field, where high welding quality is required, electron beam welding technology is gradually replacing the traditional shielded metal arc welding. Then, it is particularly important to see how the mechanical properties of the joints can be improved through the improvement of welding technology. This paper compares the microstructure and mechanical properties of welded joints of 30CrMnSiNi2A ultra-high-strength steel cylinder electron beam welding (EBW) and shielded metal arc welding (SMAW). The average tensile strength of EBW joints is comparable to that of BM. The average tensile strength of SMAW joints is only 53% of that of BM. The average microhardness of the weld zone of SMAW joints is about 335 HV, which was 186 HV lower than that of the EBW joint. The microstructures of the weld zone of the two joints were compared under transmission electron microscopy (TEM). The microstructure of the weld zone of the EBW joint was similar to that of the BM, which consisted mainly of streak-tempered martensite. Weld zone of the SMAW welded joint did not show any streak-martensite, and it consisted mainly of massive ferrite. The results of the study will promote the application of electron beam welding technology in the field of ultrahigh-strength steel fabrication.