What Is Welding Bead and Their Types?

What Is a Weld Bead?

Weld bead formation begins with the filling material added to the joint where two pieces of metal touch. The filler metal deposited from one welding pass is what we mean by a weld bead.

The bead forms directly on or within the workpiece as you are working. This is because the wire or electrode melts down and fuses to the steel. The type of bead you achieve is contingent on your technique.

For instance, stringer beads are narrow, and a stringer bead is made when you drag the torch/electrode in a straight line with little movement other than slight shaking.

The way you move the torch will dictate the type of bead you will lay in the joint. Weave beads are different because they require movement side to side while maintaining or moving forward.

You can usually tell a good weld by simply looking at it. The weld bead should run straight, even, and should be free from obvious defects (cracks, voids, or slag).

The weld bead should be strong enough that it should not be thin and voids or pits should not be found along the bead.

One important point to understand is the importance of how and where you move your torch or electrode. This is because you not only control the movement of the molten puddle but you are also dictating the shape and type of bead that gets placed in the joint.

MORE: What is Welding?

Types of Welding Bead

1. TIG Welding Beads

When done properly, TIG welds often exhibit a bead that looks like a neat “stack of dimes.” This is due to the way the filer metal is applied in equally spaced drops as the welder moves the TIG torch.

There will be a circular blob of filler metal in a drop, and when you stack drops next to each other, you begin an interesting visual process.

Equally spaced drops explains a massive difference in how a weld looks based on the pace of the travel and the feed rate of filler metal.

The faster a welder feeds the wire, the more closely stacked the drops will seem. If the welder slows down the filler feed, the drops will be spread further apart. This is one reason why TIG welding generally has a clean, aesthetically pleasing look.

However, not every TIG weld will have a look of “stack of dimes” and many skilled welders will employ a technique called “with the cup.”

With the cup means the welder is resting the filler wire on the base material, and using the cup of the TIG torch to move back and forth across the joint.

The best way to think of this is like you are spreading cream cheese on a bagel and the zig zag motion melts the filler rod on to the weld joint and allows the filler rod to be placed uniformly. This is a common technique for pipe welders.

In fact, many pipe welders will use two or three filler rods in a joint to deposit more filler metal; similar to using a couple spatulas to spread sponge cake frosting. Instead of a straight bead, it’s much more like weaving the torch back and forth for a wider and smoother finish.

2. Stick Welding Beads

Stick welding can produce several different seam characteristics depending on the electrode and technique used. The low hydrogen electrode group (7018) will be the most versatile.

Using a 7018 when running a weld, it is common to lay down what is generally called a “stringer” bead a neat, relatively narrow pass that tears an appearance of regularity to the weld.

This is very common for flat, horizontal, and sometimes even overhead positions in stick welding. While running vertically with 7018, the technique will typically be a weaving motion.

As you move uphill, you can try different weaving techniques to get the filler metal to fill the joint evenly. Weaving is usually more relaxed when welding vertically, but in some cases of welding inspectors (CWIs) could likely state that you can only use stringer passes, especially in test scenarios.

To help you out with a quick reference, please see below an example chart of our favorite welding symbols. Each symbol specifies the specific type of weld required, which also correlates to the selected bead size and style being laid down.

When using cellulose electrodes like 6010 or 7010, they can have a specific whip and pause method. For this method, your one bead will look very similar to an excellent TIG weld, perhaps not quite as shiny, but you will see the signature “dime” effect.

The process involves striking the arc, pausing to allow the “dime” to form, whipping the rod away, and returning in order to start the next “penny.” For open root welds on pipe or plate, you can also drag a 6010 rod like you would with a 7018, and you will likely get good results.

3. MIG beads

Hardwire MIG welding is surprisingly versatile, with a variety of methods with which to lay down solid welds. Some welders prefer to push the puddle, while others are more comfortable pulling. The argument over which method yields a stronger weld has been an ongoing debate for ages.

One of the main aspects of difference for hardwiring MIG is that it does not rely on a flux coating, so there is no need to drag the puddle, as would be the case with flux core methods.

In the world of welding, there’s an old saying, if there is slag, you gotta drag. This is fairly practical. With stick rods or a flux cored MIG gun, pushing the weld can trap slag right in the bead, which can lead to porosity; this would not be the case with a hard wire MIG gun because there is no flux coating.

Dragging the weld allows the slag to settle to the back side of the puddle and solidify before you pull forward with the weld to make the next puddle, thereby making sure that the weld is cleaner and stronger.

Most MIG welders utilize straight stringer beads and no weaving, bead patterns, etc. This is perfectly acceptable, and in most cases creates a solid metallic fusion weld.

However, weaving motions or patterned clockwise counter clockwise motions can be useful applied to welding wider joints, or vertically with a MIG unit, as this will help to distribute the filler metal evenly across the material joint and create a flatter, more visually appealing weld bead.

There has been a recent wave of enthusiasm for what people call the “MIG like TIG” technique. In this approach, the specific adjusted settings on a MIG can create the look of the classic TIG “dimes.”

This is often achieved by reducing the wire speed, in conjunction with some new technology present in certain models.

One thing to note, is that these “show” beads aren’t always as strong as they appear, using lower heat means it doesn’t penetrate metal as deeply. You will see them on pretty much everything going in the off-road world right now, because they are such clean beads.

MORE: What is MIG Welding?

4. Flux Cored MIG Beads

Flux core MIG welding , especially with dual shield allows for depositing a lot of filler metal quickly. Generally, most flux cored welds are run with simple stringer beads.

However, with vertical position welding, its common to use a weave pattern to better control the weld puddle.

Using a weave pattern with flux cored welding helps avoid what is called a “drip,” where the heat becomes so excessive that the molten metal drips from your work piece to the floor.

The use of a weaving pattern would make it easier to control the heat, resulting in a more consistent and controllable weld especially on vertical surfaces.

MORE: What is Flux Cored Welding?

Types Of Weld Beads Techniques

Torch manipulation follows a common pattern, whether your torch is using a filler rod that you handle separately, a wire that is fed mechanically, or even a stick electrode.

The general principles of how you will move and control a torch do not change much depending on which method you are using to weld. Certain techniques are more associated with certain welding processes, so it is important to understand these distinct differences.

Main welding bead techniques:

• Stringer beads
• Weave beads

1. Stringer beads

When welding stainless-steel pipes, stringer beads are generally run parallel to the joint. The main reason is to limit carbide precipitation, which can be a problem if there is not good control.

Therefore, stringer beads are usually suggested for welding all carbon and low alloy pipes, especially when working in the vertical fixed position.

So how do you do stringers? It is simple; it involves dragging the electrode straight across the seam; there is no weaving or sideways motion at all. Effectively, you are simply pulling or dragging in a straight line.

It is also worth mentioning that there is a big difference between stringers and weaving beads. When using weaving beads, especially when you are surfacing, you actually have more of a dilution when you have the weld puddle in contact with the previously laid bead on each pass (instead of melting into the base metal as much).

2. Weave Beads

Weaving bead techniques in welding carbon and low alloy steels can be particularly effective in positions such as rolled and horizontal fixed welding.

A fundamental practice in weaving techniques is that it allows you to maneuver the torch side to side as you weave, rather than in a straight line from point A to point B. This is not simply a decorative habit, but can be quicker than completing the welds in this position.

What sets weaving bead welding apart is that it allows you to cover a larger area with each pass. In a way, it’s built like layering paint, adding broader strokes.

When multi-pass welding in particular, one would have the dominant pattern used in a cover pass over the stringer beads that had already been laid (e.g., stacking two or more welds on the same seam).

Weaving also does not mean to walk all over the torch anyway you like. Where you locate the torch in relation to the width of the weaving technique affects the width of the bead itself. The torch could possibly end at the end of the bead with all of the edges undercut or poorly fused.

There is a guideline: the weaving width will be 2.5 to 3.0 times the diameter of the electrode. For example, if you are to weave, you are using a 3.2 mm electrode, you are to weave no more than 9.6 mm across or thereabouts, simply using the standard procedure.

It can be a wonder if there is a possibility of new methodologies in our welding routines, this wonder gets the craft to move forward.

But when executed properly, weaving will not only make the work look tidy but will also not trap slag and will remain in molten form for a bit longer, allowing any gases to escape a little better before solidification.

Therefore, the potential for porosity is reduced, and it can offer a better fusion at the edges of the weld bead. The advantage of the way you weave is to add on to the metal (metal has been added too) or replenish, in particular, one spot.

But don’t overdo it. If you make larger weaving motions, over the suggested range of 2.5 to 3.0 times the diameter of the electrode can create porous welds, and cause a relatively large false holding for alloy steels. Excessive weaving dilutes the bond between the weld metal and base metal; therefore should be avoided.

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