Influence of Welding Process Factors on Weld Formation in Butt Welded Flanges

A recent study focused on the impact of welding process factors on the weld formation of butt welded flanges has highlighted key parameters that influence weld quality, particularly in arc welding applications. The research examined the effects of gap sizes, groove forms, and wire electrode angles on weld bead formation and fusion.

Key Findings:

1. Gap and Groove Size Impact on Weld Bead Formation: When performing arc welding on butt joints, the size of the gap and the type of groove are typically determined based on the plate thickness. The study demonstrated that as the gap or groove size increases, the resultant weld bead height decreases, effectively lowering the position of the weld bead. This change results in a reduction of the fusion ratio, which can be managed through appropriate gap or groove adjustments. Specifically, leaving a gap or applying a groove leads to a more favorable crystallization condition, particularly compared to non-gap or flat groove welds.

2. Influence of Wire Electrode Angle on Weld Depth and Shape: The orientation of the wire electrode plays a significant role in controlling the weld pool and the final weld geometry. When the wire electrode is tilted forward, the arc force’s effect on pushing the molten metal backwards is weakened. This causes an increase in the thickness of the liquid metal layer at the bottom of the weld pool, reducing weld penetration. Consequently, the depth of arc penetration into the flange is reduced, and the arc’s dot movement range increases, leading to a wider weld bead with a lower height.

Conversely, when the wire electrode is tilted backward, the effects are reversed, with increased penetration and a more concentrated heat input into the weld pool. The research found that a forward wire electrode tilt angle tends to create a broader weld, while a backward tilt, often used in stick electrode welding, enhances the depth of penetration.

3. Effect of Wire Angle on Weld Quality: The study emphasized the influence of the wire electrode angle on weld formation. The optimal tilt angle for stick electrode welding is found to range between 65° and 80°, which balances the molten pool’s behavior and allows for greater control over the weld's final shape. This tilt angle helps prevent excess spatter and ensures better penetration and bead consistency.