What are the advantages of seam welding

Seam welding: uses, advantages and disadvantages

Seam welding is the art of welding two materials together using the heat generated by the electrical resistance.

Seam welding is the process of joining two similar or dissimilar materials at the seam using electrical current and pressure. The process is mostly used with metals because they can conduct electricity easily and withstand relatively high pressures.

Seam welding is possible thanks to the contact resistance created between the two metals.

When electricity flows between the metals, heat is generated at the small gap. Electrodes receive and control the flow of current.

Let's go into the details of this welding technique, which is used in a wide variety of industries.

What is resistance seam welding?

Seam welding or resistance seam welding is a subgroup of resistance welding, in which two materials are welded with an electric current.

There are mainly four types of electrical resistance welding:

Resistance seam welding is one of the most common welding processes for joining sheet metal with a continuous weld seam.

When two similar or dissimilar materials are pressed together, a slight gap is created between them due to surface irregularities. When welding resistance seams, this gap creates an electrical resistance between the two materials and causes them to heat up at the seam.

This is also known as contact resistance.

When welding seams, the welding current is of primary importance. The amount of heat generated at the seams depends on the magnitude of the current flowing through them.

However, increasing the current too much can result in ejections and electrode degradation. Alternating current (AC) is still the preferred type of electrical current used in seam welding.

The seam welding process uses wheel-shaped electrodes. These wheels apply power and electricity to the workpieces.

The welding force should be proportional to the hardness of the materials. Therefore, harder metals require more welding force compared to softer metals.

In a broader sense, resistance seam welding is categorized into

Seam welding with intermittent movement

The rollers and the electrical power supply remain active until the welding position is reached. This means that the weld will be made at specific points or areas rather than as a continuous line.

Intermittent motion seam welding is useful for welding thicker metals when a continuous weld is not possible. There are two types of intermittent seam welding:

Continuous motion seam welding

With continuous seam welding, a continuous weld seam is possible. The metal bonds with a constant roller speed as it passes through the electrodes. It creates a uniform, overlapping weld as the workpieces remain under constant pressure.

The type of electrodes used in resistance welding depends on the material to be welded. For example, if we weld aluminum by seam welding, then copper electrodes are often avoided. This is because copper alloys with aluminum, causing the electrode to deteriorate much faster.

Laser seam welding and resistance seam welding

The term seam welding has almost become a synonym for resistance seam welding. But there is also another seam welding process, laser seam welding.

Laser seam welding is a variant of laser spot welding. In laser spot welding, a high-intensity laser is aimed at a point where the beam causes the target point to melt and weld.

In this case, however, the laser tool head is stationary. With this welding technique, the laser moves along the seam to create a constant weld seam.

This type of welding technique is commonly used to weld sensors, radar components, insulin pumps, battery cases, and pacemaker cases.

Advantages of resistance seam welding

Resistance seam welding has a unique set of advantages that make it very beneficial in many industries.

Airtight welds: One of the most important properties of a continuous weld is that it can create airtight and watertight seals. This is very important in the manufacture of metal structures that need to be protected from air or water leakage, such as airtight or liquid-tight containers.

Fast welding process: welding is possible at high speeds. And since the entire process is automatic, resistance seam welding is faster than other alternatives such as spot welding.

No filler / flux required: The weld seam is possible without the use of filler material or flux.

Disadvantages of resistance welding

The way in which resistance seam welding is set up has several disadvantages. Below are some of the limitations or disadvantages of resistance seam welding.

Limited weld lines: Since seam welders consist of rollers, only straight or evenly curved line welds are possible.

Thickness Limitations: There are limitations when it comes to the thickness of the sheets as the seam welding can become quite cumbersome when the thickness of a single sheet is more than 3mm.

Applications of seam welding

Resistance seam welding is used in the assembly of fuel tanks, as it has to be liquid-tight. It is also used for welding parts of containers that need to be watertight or airtight.

Some other forms of welding can also create watertight and airtight seals, but they do not necessarily ensure a clean weld. Similar to what can be achieved by seam welding.

The other common use is in welding pipes and hoses. Resistance seam welding is used particularly in this area because no molten metals are used.

Therefore, there are no weld beads that would ruin the aesthetics of the pipes or tubes. This welding technique is able to produce seamless connections that hardly feel at the connection surface.

Seam welding is also used in the manufacture of sheet metal tanks, which are used as containers for kerosene, gasoline and other liquids. Both the airtight and the liquid-tight weld seams play a role in such an application. This is because liquids like gasoline evaporate when they come into contact with air.

Resistance seam welding can be found in many industries due to its unique weld seam capabilities. Like any welding process, it has a number of advantages and disadvantages.

For a certain catalog of requirements, however, resistance seam welding is ideal in terms of its performance and welding options.