Effect of Electron-Beam Welding Parameters on Characteristics of Bead Section

Studies on Electron-Beam Welding, 5

Abstract

The effects of anode voltage, welding current, beam diameter, welding speed and thickness of specimen on the characteristics of bead section (such as, penetration, width and penetration-to-width ratio) were studied with the 1.5 kW NRIM electron-beam welding equipment for type 304 stainless steel, low carbon steel, aluminium, brass, zirconium and titanium.
The following conclusions were obtained:
(1) An increase of anode voltage or welding current increased the penetration greatly and the width slightly. An increase of beam diameter greatly reduced the penetration but increased the width. An increase of welding speed coordinately reduced both the penetration and width.
(2) New parameters were introduced to correlate satisfactorily the effects of anode voltage (V), welding current (I), welding speed (ν) and beam diameter (φ) on penetration (ρ) and width (ω) in bead welding; that is:
ρ=κ_a×Ε^1.7×Ι¹/ν^0.4×1/φ^0.8
ω=κ_b×Ε^0.1×Ι^0.2/ν^0.5×φ^0.6 (φ<8mm)
ρ/ω=κ_c×Ε^1.6×Ι^0.8×ν^0.1×1/φ^1.4
where, k_a, k_b, and k_c arc constants which depend on the material.
(3) An electron-beam was shown to cause a deep and wedge-shaped penetration in various materials, provided a sufficient weld heat input which exceeds a critical value is used for a given beam diameter.
(4) The effect of plate thickness on bead characteristics for a given welding condition is slight only for metals of poorer heat conductivity and comparatively high welding speeds.