A Study on Occurrence and Prevention of Defects of Electron Bean Welding (Report No.1)
Blow hole and Void of Electron Beam Welds of Carbon Steels
1974 Volume 43 Issue 7 Pages 678-683
Details
1974 Volume 43 Issue 7 Pages 678-683
Six types of plain carbon steels were electron beam welded using a 150kV high vacuum type machine. In the preliminary testing, a set of welding parameters was selected which produced the largest amount of blow-holes and voids at 20 mm penetration. Using this condition, effects of beam oscillation (X, Y, circle) of various frequencies and double welding on defect-formation were investigated.
It was found that 100 to 1000 Hz X(in line of welding) beam oscillation and double pass welding were effective to prevent above mentioned defects, and (C) × (O) showed the best coincidence with the tendency of defect-occurrence.
These findings suggest that formation of CO gas during welding is the main cause of blow-holes and voids, however (Mn) contents showed the same degree of coincidence which suggest another mechanism of defect-formation as proposed by Arata et al. Conclusions are left to further studies.
Spikes did not change appreciably among six materials, and this fact seems to support the theory proposed by Tong.
From metallurgical investigations, the anthers propose to adopt qp=EI/vp (J/cm2, where E: accerelating voltage kV, I: beam current mA, v; welding speed cm/sec, p: depth of penetration cm) parameter for metallurgical as well as deformation and stress analysis.
