What Are Welding Beads?

In the complex world of welding, welding beads are the foundation and structural point of each weld joint. But many new welders wonder what welding beads are.

Fundamentally, a welding bead results from melted filler material that bonds two or more metal pieces together. However, the science behind weld beads is a fascinating and complex process worth delving into.

That's why this article delves into the fundamentals of welding beads, exploring types, formation processes, and their significance in structural integrity.

What Is A Welding Bead?

A welding bead is a seam deposit of molten metal that forms during welding in a single pass. At its core, a welding bead forms once the filler metal and base metal are heated to their melting point. As the filler melts, it creates a molten weld pool that penetrates and fuses the pieces. Once everything solidifies, you get a welding bead or, simply put, a weld.

Even though weld beads are the structural and straightforward pieces of the weld, they greatly vary depending on the welding machine settings and technique. The final goal is to create a uniform weld bead that properly fills the joint and penetrates the two pieces.

However, that is often the most challenging task for most beginner welders. So, let's discuss the properties of a weld bead and the differences between good and bad welding beads.

How Do You Create A Welding Bead?

Creating a weld bead involves preparing the metal surfaces, securing them in place, selecting the correct welding method, adjusting power settings, igniting the welding torch, and feeding filler material into the weld pool at a steady rate.

While this is enough to create a weld bead, its appearance and properties will significantly vary depending on your torch movement and dialed-in settings. Welding in harsh conditions and uncomfortable positions where you battle gravity will also impact the strength and properties of the weld bead.

Welding Bead Geometry

Each weld bead has its size, length, width, and profile, which can tell you much about the weld you just performed. As noted, these properties will vary depending on your welding technique, welder settings, and torch manipulation, and getting a uniform weld comes with time and practice.

Source: https://weld.theweldings.com/2021/08/weld-bead-and-its-properties.html

• Welding bead height: The height of the welding bead is related to the amount of filler material deposited into the welding joint. Many welders make a mistake by depositing the more needed filler, hoping it will make a stronger weld. The strength of the weld depends on the penetration rather than the size of the reinforcement. Too much filler creates higher costs, increases the weight of the weldment, and is not always visually appealing. Too little filler, on the other hand, can cause a lack of penetration or improper tie-in, so consistency is crucial.
• Weld bead width: Too-wide beads often indicate shallow penetration but are sometimes used in wider gaps. While that's desirable in some applications when there is a risk of burn-through, you want to stay within the bounds. Narrow weld beads typically indicate higher penetration but can result in improper weld tie-in.
• Weld bead length: As a beginner, you are likely to create continuous welds across the joint, but welding specifications can require multiple shorter beads or spot welds. Stitch welds, or intermittent welds, are several shorter welds across the joint that are used to prevent heat distortion. Your weld bead is just a tiny dot in the spot or tack welding.

• Welding bead profile: a weld bead profile can be flat, convex, or concave. In most applications, and certainly as a beginner, you will want to get flat welds. Convex fillet welds have an exterior surface that curves outward, representing an excessive reinforcement. Concave fillet welds have an exterior surface that curves inward, representing a lack of reinforcement to the weld.

Good Vs Bad Weld Bead

Now that you understand the structural parts of each weld bead, we can explain the differences between good and lousy welding beads. The criteria that help you distinguish good from bad weld beads are appearance, weld profile, penetration, colors, visual defects, and undercutting.

Types Of Welding Beads

The orientation and appearance of the weld beads are highly dependent on the torch manipulation, whether you are using a MIG welding gun, TIG welding torch, or Stick welding electrode holder. Depending on the way you move your torch across the joint, there are two primary types of welding beads:

• Stringer beads
• Weave beads

Source: https://smooth-robotics.com/weaving-in-welding/

However, there are also process-specific torch manipulations and weld beads, such as whip motion, used in stick welding, and walking the cup, used in TIG welding.

Let's discuss more about each.

Stringer Beads

Stringer weld beads are the most common type of welding beads you are likely to use as a beginner or a new welder. To create a stringer bead, you push or pull your torch in a straight line across the joint with little to no side-to-side movement. This is the most straightforward weld bead technique, and it will be your best friend as you learn how to weld.

Even though stringer beads include running in a straight line, several other things can still affect the weld bead appearance. You must also consider the push or pull technique, welding speed, and welding parameters.

Push Vs Pull Weld Beads

In the world of welding, push vs pull welding is an everlasting debate with no clear winner. Pushing involves working behind the weld pool, pushing it with a welding electrode, and creating the weld bead as it goes. Pull welding, also known as drag welding or backhand welding, includes pulling your weld puddle.

Source: https://www.wcwelding.com/mig-welding-tips.html

While there are only minor differences, one technique can be more suitable for specific applications. For example, pushing is known to produce minorly shallower penetration, which is good for thin metal and allows you to control and see where you are heading. Meanwhile, pulling or dragging produces somewhat better penetration, which is suitable for thicker pieces and prevents slag inclusions.

Regarding MIG welding, pushing or pulling is a matter of personal preference, but most welders prefer to pull since it is easier to learn and perform. Slag welding processes, including Stick welding and flux-cored arc welding, require pulling the weld bead to avoid slag inclusions. Remember the phrase: if there is slag, you drag. Finally, in TIG welding, you push the weld bead for smooth filler metal distribution.

Welding Speed And Parameters

Welding speed and weld parameters are also crucial in weld bead formation. As noted many times above, consistency is vital in achieving a smooth and uniform weld bead.

Going too slow will expose the base metal to too much heat and filler metal distribution. This can lead to a burn-through, where your weld completely penetrates the pieces and burns holes. Meanwhile, going too fast will create a lack of penetration. The weld bead will sit on top of the pieces without penetrating the weld joint, creating weak welds prone to failure.

Welding parameters can have similar results to welding bead creation and performance as welding speed. Too much heat can burn through the pieces, while too little creates incomplete fusion. However, in some applications, there is a close relation between speed and parameters.

For example, you must reduce the heat and increase the speed when welding in a vertical up position. That way, you prevent molten metal and a weld puddle from escaping the weld joint. On thick pieces, you increase the heat and reduce the speed to get a proper weld bead penetration.

Weaving Beads

Unlike stringers, weaving beads involves traveling across the joint with weaving side-to-side motion. This advanced technique is often used when you need to fill large weld joints on thick stock. In these applications, stringers will just fill the middle of the joint without proper tie-in, so you must weave.

As a result, weave weld beads include zigzag, crescent, or curly shape motion of your torch. There are different types, such as triangle weave beads, circular weave beads, convex or concave weave, and ladder weave, and the choice depends on specific applications and the personal preferences of each welder.

Advantages of Weaving Weld Beads

Even though weaving is not as easy as stringer beads, it has advantages in heat distribution, which is crucial when welding thick stock with large joints or groove openings. Moving the torch from side to side allows you to distribute the heat and deposit the filler metal evenly.

Doing so provides enough heat and filler to both the central part of the weld and the toes. Welding thick pieces often produces a lack of penetration or undercut, and weaving deals with both. Moving to a side of the joint and spending some time provides good tie-in while moving faster through the center of the weld prevents excessive reinforcement or convex welds.

Triangle weaving beads are handy in a vertical-up welding position. As you move in a triangular motion, you build a shelf behind the puddle, preventing molten metal from sliding downward. Meanwhile, crescent or semi-circular motion is good when there is a larger joint, and you want to avoid the puddle from overheating or expanding.

While weaving beads is more challenging, complications arise in overhead welding. Preventing molten metal from dripping or falling onto your face can be highly challenging when weaving, and only seasoned welders can do this safely.

Whipping Technique In Stick Welding

Stick welding a root pass with E6010 electrodes can be challenging to use due to their fast-freezing nature. That's why welders often use the whipping technique, a variant of weaving motion.

Source: https://www.engineeringskillscomp.org/

In this technique, you form a puddle and pull the electrode entirely out of it using your wrist in a whipping motion toward the direction of travel (letting it freeze). Then, you bring it back to the leading edge of the puddle and start a new puddle, and so on, until you finish your bead.

This coordinated motion cools everything down and keeps the keyhole size constant. It also allows the bead at the back of the puddle to solidify, creating a uniform and even welds. All of this happens pretty quickly, so whip motion is considered one of the most challenging to master. However, once you put enough hours into practice, you unlock the ability to weld with even the hardest electrodes, such as E6010s.

J-Weave Weld Bead

J-weave weld bead is a variation of whipping motion, which is also used with E6010s but is now on a hot pass. A hot pass is typically a second pass in a multi-pass pipeline welding or thick stock carried out immediately after the root pass to improve or correct mistakes in a root pass.

This weave motion presents a combination of the crescent and whip strokes. Using a longer arc, you move your torch like whipping but with brief pauses on each side. After whipping ahead, you'll whip back to the next open area, and so on, until the end of the weld joint.

As part of the hot pass, J-weaving can correct the tie-in issues with the root pass. Spending more time on the sides ensures your weld properly fills the root pass, which is essential for creating a solid foundation for multi-pass welding.

Walking The Cup Weld Bead

Walking the cup is a unique weld bead technique used when TIG welding pipes, but it can also be used on fillet or groove weld joints. This weld bead type involves resting the TIG cup on the side walls of a fillet weld or on the beveled walls of a groove weld.

This technique is useful when you must weld for a reasonably long run without stopping. Since you are resting your cup on the base metal, the hand fatigue is significantly lower, so you can focus on proper filler rod feed and weld bead.

To walk the cup, you must use a larger cup, and the size varies depending on the depth of the groove, the angle of the groove, or the size of the weld deposit. The goal is to use a cup that can firmly sit on the edges of the base metal without touching the weld that is being deposited.

Since walking the cup is typically used on grooves and roots, you will have to weave the cup back and forth along the weld joint. That's why this technique is also considered part of weaving motion beads.

Final Thoughts

Welding beads serve as the cornerstone of welded joints, essential for uniting metal pieces across diverse industries. Their formation involves meticulous preparation, precise execution, and careful inspection to ensure structural integrity and durability.

Whether it's arc welding, MIG, TIG, or oxy-acetylene welding, the process remains consistent: melding filler material with base metals to create a seamless bond. Understanding welding beads is not just a skill; it's an art form that underpins the construction of everything from towering skyscrapers to intricate machinery.

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