Possessed of a laser-like focus, good welders control weld beads. A depth-regulated seam progresses between two joint zones. As the filler metals and weld pool cool behind the travelling electrode, it produces a solid joint that’s just the right width. This seam is smooth and free of excess weld metal. From the smooth, clean joint face to the root and toe, the weld bead hardens into an imperfection-free join.
Talking About Weld Bead Size Issues
At least that’s what should be happening. Every time a skilled welder lays down a weld bead
that should be the final result, a smooth joint that penetrates to the core of the two intersecting metal surfaces. If the fusion line isn’t wide enough, then the weld depth ratio is going to suffer. Without full penetration, the joint weakens. For a small weld bead, multi-pass welding can fix this issue. If the bead is too broad, however, then a void could form between the weld filler and the root of the joint. Again, the jointed plates end up weak because the filler hasn’t penetrated deep enough into the joint interface.
Weld Shape and Width: Analyzing Weldment Geometry
Using two plates to illustrate the next set of welding challenges, the two workpieces are cleaned and placed at ninety-degrees to one another. Using a GMAW (Gas Metal Arc Welding) rig, a properly sized weld bead is applied. A triangular fusion line follows closely behind the powered arc as it melts the filler material. The metal melts then cools. In reality, it’s more of a wedge-shaped joint. The face is visible as a slightly rippled metal line, which joins the two metal parts. With the equipment charge and feed rate adjusted, the desired weld bead size has been achieved. Now, the geometry of the bead is maintained by keeping the electrode at a set angle, unless the welder suddenly develops a nervous tic.
It’s not just the electrode angle that creates weld bead discontinuities; the equipment voltage and amperage settings also require attention. Welders should confirm the viability of those settings by working on a waste piece of metal. Then, with the arc length consistent and the power supply settings adjusted just-so, the rest is up to the welder, so no nervous tics, please. To keep things flowing smoothly, the equipment operator should find a comfortable position, take a cleansing breath, and then adopt a moderately fast travel rate. If it’s too fast, though, the depth and shape of the weld bead won’t form as a clean, consistent seam. Fast travel speeds also cause bead-corrupting problems.