4 razões para a aderência do eletrodo durante a soldagem

4 reasons for electrode sticking during welding

Sticky electrode refers to an abnormal welding between the electrode and the workpiece, causing the electrode to adhere to the workpiece. This can cause the electrode to be torn off or the part to rust, especially if the flow of cooling water is interrupted.

There are four main causes of electrode sticking during welding: misalignment of the working surfaces of the two electrodes, roughness on the working surfaces of the electrodes, insufficient electrode pressure, and improper connection or blockage of the cooling water circulation at the welding outlet. gun.

1. The working surfaces of two electrodes are not parallel

If the working surfaces of the two electrodes are not parallel, this may result in localized contact between the electrode working surfaces and the workpiece. This increases the contact resistance between the electrodes and the parts and decreases the current flow in the welding circuit.

Related Reading: Wire Feed Speed ​​and Welding Current

When the current is concentrated at a localized contact point and the current density at that point is greater than the normal current density of the electrode's working surface, the temperature of that point will rise and reach the welding temperature of the electrode and workpiece. . This results in the electrode and workpiece fusing.

2. Rough electrode working surface

If the electrode working surface does not properly align with the part and only comes into contact with certain protrusions, this will result in misalignment between the two electrode working surfaces. This may cause the electrode to stick.

3. Insufficient electrode pressure

Contact resistance is inversely proportional to pressure. If the electrode pressure is insufficient, the contact resistance between the electrode and the workpiece will increase. Increasing the thermal resistance at the contact point will increase the temperature of the contact surface between the electrode and the workpiece to the welding temperature, resulting in a fusion connection between the electrode and the workpiece.

4. The water pipe at the welding gun cooling outlet is connected reversely or the cooling water circulation is blocked

If the water pipe at the cooling outlet of the welding gun is incorrectly connected or the cooling water circulation is blocked, the electrode temperature will increase, potentially causing a melt connection between the electrode and the workpiece during continuous spot welding .

The four conditions mentioned above are potential causes of the fusion connection between the electrode and the workpiece, leading to electrode sticking.

To prevent electrode sticking, it is important to take steps to avoid these conditions.

(1) To prevent electrode sticking, the working surfaces of the two electrodes must be parallel and free from rough defects, filing the electrode head. The welding program can be set to the grinding program (no current output), and the two electrode working surfaces can be checked for parallel alignment using an empty welding gun.

(2) In the grinding state, the welding should be air drilled 5 to 10 times to forge the working surfaces of the two electrodes, increasing the contact area within the specified range of electrode tip diameter and improving the surface hardness .

(3) The electrode working surface can be heated with an oxyacetylene flame to form an oxide layer (oxide build-up), which improves the melting point of the electrode working surface and reduces its weldability to the workpiece.

(4) The working surface of the electrode can be coated with red lead, as configured by the welder, to reduce its weldability to the workpiece.

(5) The electrode pressure should be adjusted, and welding parameters of high pressure, high power and short switching time should be used.

(6) The cooling water pipe must be cleaned regularly to ensure adequate cooling water flow.

These measures can help solve the problem of electrode sticking during welding.

Recommended for you:

  • Welding Training 101: Everything You Need to Know
  • Welding Glossary: ​​292 Crucial Welding Terms
  • Spot welding: detailed guide and techniques revealed
  • Common Welding Processes for Thin Plates: Expert Guide
  • Special Foundry: Everything you need to know
  • Spot welding: tips and techniques for precision bonding

Conteúdo relacionado

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.