Importance of Cooling in Seam Welding

WELD COOLING

The cooling system during welding is very important for controlling the seam welding process. Its main role is to minimize thermal damage to the outer surfaces of the weld, while the interface between the parts is heated above the melting point. Key elements for the success of the weld cooling system are:

• Disc material (thermal and electrical conductivity)

• Disc profile (radius)

• Disc cleaning (There must be a device for cleaning the discs, particularly when the welded material is coated)

• Disc cooling system

• Water cooling applied directly to the weld (if applicable). The cooling water for seam welding discs can be internal or external. Internal cooling systems are used to cool the discs, but not the weld. The main advantage of internal cooling is that the process is dry. The workpiece, the machine, and the operator do not come into contact with water. The cost of installing floor drains and water containment facilities is avoided. It is also not necessary to install devices to remove water from inside the workpiece (e.g., in the case of automotive fuel tanks). However, the internally cooled system can cost more due to additional machining costs. Thus, operating costs for internal cooling can be higher than for external cooling. Some internal systems do not directly cool the roller, but only the wheel axle. On the other hand, with external cooling, spray nozzles are directed with some precision at the separation point of the work rollers.

The benefits of external cooling include:

• Thermal damage to the weld surface and coating is avoided to improve weldability;

• Reduction in welding distortion;

• Reduction of fumes during welding;

• Improved cleanliness in the weld area because water is applied at the hottest point of the disc;

• Higher weld strength in certain seam welding processes;