Electron Beam Welding of High-Strength Aluminium Alloys

摘要

High-strength aluminium alloys are widely used in high-performance automobiles, railway cars, aircraft and spacecraft, light ships, etc., owing mainly to their excellent mechanical strength, low specific weight, good formability, and relatively low cost. The present paper reports the results from the study of the influence of the electron beam oscillation patterns and travel speed on the melting efficiency, the weld geometry, the structure and the mechanical properties of the welds of Al-Mg alloys with nominal composition wt% Mg(5.8÷6.8), Mn(0.5÷0.8), Si(0.4), Fe(0.4), Zn(0.2), Cu(0.1), Ti(0.1) balance Al. Electron beam welding was performed to connect details of up to 25 mm thickness with beam oscillation of various patterns (sinusoidal, square, triangular and elliptical) using a 15 kW Leybold Heraeus welding equipment. For comparison welding without beam oscillation was also carried out. The melting efficiency is determined from the measured welded seams cross-section for a specified electron beam power and travel speed. The theoretically calculated values of melting efficiency are obtained using moving heat sources equation. The quality of the weld (porosity, sensitivity to cracking), the microstructure and hardness of the welded seam in comparison to the base materials were also investigated.