What is Seam Welding | Symbol | Application | Advantage & Disadvantage

Seam Welding Process

Seam Welding is a type of welding in which the electrodes are in disc form unlike stationary rods & are driven through the motor in the presence of current.

Basic Principle of Seam Welding

Two electrodes made from copper & in circular form are used. An impulse current is applied through one of the discs & pressure through the other on the materials that are being joined.

When the material passes between electrodes they rotate. In this way, the electrode remains in contact with the material for a long time & forms a weld joint progressively unlike spot welding which forms an entire joint at once.

Seam welding core principles are similar to that of the Resistance spot welding. Time, pressure & electricity are used to weld metals together. It is a type of electric resistance welding.

If the current is quickly turned OFF & ON a continuous fusion zone of overlapping nuggets is formed then this process is called as STICH WELDING PROCESS.

The process of seam welding can be controlled to create a variety of welds like

  1. Spot Welds
  2. Overlapping Welds
  3. Continuous Welds

Seam welding machine images

 

Seam Welding Machine image

Seam Welding Machine image-2

Seam Welding Machine image-3

Current Supply

A transformer is used to provide energy to the welding joint in the form of low voltage, high current AC power.

How Current Flows?

The electric current flows in pulses to produce a row of welds along the travel path.

Types of Electrodes

Copper electrodes in discs form are used in this welding. The purpose of the copper electrodes is to keep the heat MINIMUM at the contact surface.

Types of Seam Welding

There are two types of this welding

Continuous Motion Seam Welding

In this type of seam welding, as the name suggests the electrodes are rotated at predetermined constant speed & overlapping welds are formed when current impulses are timed. There is another way to do it as well in which workpieces are moved at a constant speed while the electrodes keep idling under the welding pressure.

Intermittent Motion Seam Welding

In this type of seam welding, the workpieces are allowed to move automatically from one welding position to another & so on. This technique is useful for thicker materials sheets which can’t be properly weld by the continuous motion weld technique.

Forms of Seam Welding

  • Standard Seam
  • Mash Seam
  • Roll spot Welding

Standard Seam

When electrode wheels are rotated along the workpieces & continuous series of current pulses are fired then a series of overlapping weld nuggets are formed. Continuous, leak-tight joint is formed as a result of this welding.

Mash Seam

In mash welding a small sheets overlap occurs, that is one to two times the thickness of the sheets. When current is applied then sheets are then mashed together which forms a solid-state joint. The thickness of the welded joint is 110-150% of the original sheet thickness. This joint thickness can be reduced at the end by post welding planishing.

Roll spot Welding

In roll spot welding current pulses as the wheel travel across the workpieces to form a separate line of spot welds.  The joint formed due to this welding is not a leak tight joint.

Types of Seam Welding Joints

Lap Seam Weld
  • The type of weld in which the two workpieces slightly overlap along the edges is called as lap seam weld. The overlapping metal is mashed & welded at the same time.
Butt Seam Weld
  • The type of welding in which the edges of sheets are joined & welded to form a butt joint is called as butt seam welding. This technique is mainly used for manufacturing of welded pipes. An electric current is used to heat the metal in the weld zone.

Seam Welding Diagram

 

"<yoastmark

Download Seam Welding PDF FromHERE

Seam Welding Symbol/Drawing

Seam Welding Machine symbol

Seam Welding Equipment

Equipment

This welding equipment include

  • Welding electrodes made from copper which are in discs form
  • Ac power supply source i.e. transformer
  • Welding metal sheets i.e. workpieces
  • Sliding contact

Download Seam Welding PPT FromHERE

Seam Welding Advantages and Disadvantages

 

Advantages
  • This welding is a quicker process than spot welding.
  • It is a continuous welding technique suitable for gas & liquid tight containers.
  • Energy is utilized efficiently in this technique.
  • This technique is ideal for making gas or liquid tight vessels.
  • It doesn’t need the use of filler material.
  • No pollutions like fumes of gases because filler material is not utilized.
  • This technique can produce liquid tight & gas-tight joints.
  • Since the joint is forged due to heat & pressure, a durable weld is formed in seam welding.
  • This welding is easy to operate.
  • Seam welding gives sturdy design & excellent performance.
Disadvantages
  • Higher current is required as compared to spot welding.
  • For harder alloys, high strength welding forces are required.
  • The electrode may need to be cleaned after one revolution.
  • The mechanized cleaning system is necessary for removal of contaminations.
  • This technique is not utilized when the thickness of the sheets increases from 3MM.
  • If electrodes & ravel speed is not controlled efficiently then its performance may be decreased.
  • Workpieces need to be overlapped to make sure that no overflow of melted metal occurs.
  • It requires a greater amount of current.
  • Its electrodes are motor driven as compared to stationary electrodes.

 

SEAM WELDING APPLICATIONS

 

Applications

Seam welding applications include

  • It is used in the assembly of fuel tanks in the automotive industry.
  • Especially used in case of seam-welded tubing & pipes.
  • It is used when fabrication of gas or liquid tight metal sheets are needed.
  • It is also used in the fabrication of heat exchangers.
  • Earlier seam welding was used to produce steel beverages cans but not currently used.

 

Seam Welding Machine Specifications

  • Mostly available in circumferential, longitudinal & universal types
  • Wide range from 50 KVA to 200 KVA
  • Variety of models available i.e. 55-A, 55-B, 55-C 

 

FAQ’s

What is Resistance Spot Welding?

The type of welding in which the two contacting surfaces are joined from the resistance obtained from the electric current is known as Resistance Spot Welding. It is a type of electric resistance welding.

What is the difference between seam and spot welding?

There are Lot of similarities in seam welding & spot welding like both techniques make individual welds. The heating principle is the same in both which is OHM’s law. But the main difference is both use different types of electrodes. This welding uses wheel electrodes while spot welding uses point electrode. Seam welds are closer together & produce liquid-tight seals. While spot welds are not close together & are not water-tight. While spot welds are not close together & are not water-tight. Seam welding wheels are not stationary while spot welding wheels are stationary.

Read more about  Welding

Read more about Magnetic Pulse Welding

Read more about Types of Welding Joints

If you have got any questions make sure to comment below.

Summary
What is Seam Welding | Symbol | Application | Advantage & Disadvantage
Article Name
What is Seam Welding | Symbol | Application | Advantage & Disadvantage
Description
In seam welding electrodes are in disc form unlike stationary rods & are driven through motors in the presence of current. Pros | Cons | Applications
Author
Publisher Name
The Welding World
Publisher Logo

Reply