Resistance welding is a widely used welding process in the fields of automotive manufacturing, aerospace, electronics and electrical appliances, etc. Its principle is to use the resistance heat generated when the current passes through the contact surface of the workpiece and its adjacent area to locally heat the metal to a plastic or molten state, and form a welding joint under pressure. However, in actual operation, the phenomenon of 'weak welding' often occurs, seriously affecting the quality of welding and the safety performance of the product. This article will discuss from multiple aspects how to effectively avoid the occurrence of weak welding in the resistance welding process.



One, Definition and harm of false welding



False welding refers to the welding joint that does not form an effective metal bond during the welding process. It appears to be welded externally, but in fact, there are gaps or incomplete fusion inside. False welding not only reduces the strength of the weld but may also cause the joint to break, leak electricity, or have poor contact during use, especially under high temperature, high pressure, or vibration conditions, posing a great safety hazard.



Two, The main reasons for false welding



1. Insufficient electrode pressure: Insufficient electrode pressure will lead to poor contact between the workpiece and affect the conduction of current and the concentration of heat.

2. Insufficient welding current or insufficient time: Insufficient current or too short welding time cannot make the metal reach the required plasticity or melting state.

3. Contamination or oxidation of the workpiece surface: The presence of oil, oxides, or coatings on the metal surface will hinder current flow and affect welding quality.

4. Electrode head wear or contamination: After long-term use, electrode heads may wear or be contaminated with impurities, leading to uneven heat distribution.

5. Large differences in material thickness or conductivity: When welding metals with different thicknesses or conductivities, it is easy to cause unbalanced heat distribution, affecting fusion effects.



Three, Specific measures to avoid false welding



1. Optimize welding parameter settings

According to the type, thickness, and welding requirements of the workpiece material, reasonable parameters such as welding current, time of electricity, and electrode pressure should be set. Precise adjustment can be made with the help of welding parameter optimization software or empirical formulas.



2. Ensure the cleanliness of the workpiece surface

Before welding, the workpiece surface should be thoroughly cleaned of oil, rust, paint, oxide scale, and other impurities. Mechanical polishing or chemical cleaning may be used for pretreatment if necessary.



3. Regular maintenance and replacement of electrodes

Electrodes should be cleaned in time to avoid carbon accumulation or foreign objects affecting conductivity. Electrode heads with severe wear should be replaced in a timely manner to ensure heat concentration and uniformity in the welding area.



4. Use appropriate electrode materials and shapes

Select appropriate electrode materials (such as chromium zirconium copper, aluminum oxide copper, etc.) according to the welding material, and design reasonable electrode shapes to improve heat dissipation and conductivity.



5. Strengthen welding process monitoring and testing

Introduce real-time monitoring systems (such as current, voltage monitoring, pressure sensors, etc.) for dynamic control of the welding process. At the same time, destructive or non-destructive inspections (such as X-ray, ultrasonic testing, tensile tests) are carried out on the welding joint to detect false welding defects in a timely manner.



6. Carry out process tests and verification

Conduct welding process evaluation before formal production, verify the rationality of parameters through trial welding and testing, and ensure stable and reliable welding quality.



Four, Conclusion



In summary, false welding is a common but extremely harmful defect in the resistance welding process, with complex causes involving materials, equipment, processes, and operations. To effectively avoid false welding, it is necessary to start from the source, scientifically set welding parameters, strengthen process control, and pay attention to equipment maintenance and personnel training. Only through systematic and standardized management can the reliability and product quality of resistance welding be truly improved, providing a solid guarantee for various industrial manufacturing.