Fundamental Study of High Power Electron Beam Welding. II.--Effect of Beam Oscillation on the Elimination of Porosity

• Published in: Yōsetsu Gakkai-shi Vol. 51; no. 1; pp. 27 - 32
• Main Authors: Masumoto, I, Kutsuna, M, Yasuda, K
• Format: Journal Article
• Language: Japanese
• Published: 01.01.1982
• ISSN: 0021-4787

The use of EB welding for thick materials confers the benefits of high quality, low distortion, and short welding times in the case of single-sided, narrow-pass welding. Centre porosity can occur in single-side, deep-penetration welding and its repair by welding methods can be difficult. To prevent the occurrence of such defects, a beam oscillation technique was tried on 50, 100, and 150 mm thick pletes in type A387D steel (composition C 0.12, Si 0.22, Mn 0.54, P 0.006, S 0.007, Cr 2.29, Mo 1.07%). The experiment and results can be summarized as follows: (i) a slow speed of welding effectually eliminated porosity; (ii) the conditions of beam oscillation studied were at frequencies of 500-2000 Hz, at amplitudes 0.5-2.0 mm and at sine, cyclic, or elliptical patterns of oscillation; (iii) when the beam width was increased by an excessive amplitude perpendicular to the welding direction, a solidification crack developed along the centre line of the weld metal; (iv) beam oscillation was found to reduce porosity but under optimum oscillating conditions, the bead shape, on the reverse side was irregularly under filled; and (v) the range of conditions under which porosity was avoided by the beam osillation technique was narrow but beam oscillation parallel to the direction of welding was an effective method of eliminating porosity. 12 ref.--BA.