Analyzing Electrode Materials for Intermediate Frequency Spot Welding Machines

Intermediate frequency spot welding machines require electrodes to complete the welding process. The quality of the electrodes directly affects the quality of the welds. Electrodes are mainly used to transmit current and pressure to the workpiece. However, using inferior electrode materials can accelerate wear during use, leading to increased grinding time and wastage of raw materials. Therefore, it’s important to select electrodes based on the materials being welded.

Electrodes need to have a certain level of high-temperature hardness, especially to maintain this hardness at temperatures between 5000-6000°C. Higher high-temperature hardness prevents electrode stacking during the welding process. Typically, the temperature at the contact surface between the workpiece and the electrode during welding is about half the melting point of the welded metal. If the electrode material has high hardness at high temperatures but low hardness during welding, stacking can still occur.

The working end of the electrode comes in three shapes: cylindrical, conical, and spherical. Conical and spherical shapes are more commonly used because they enhance cooling and reduce electrode temperature. Although spherical electrodes have a longer lifespan, faster heat dissipation, and better weld appearance, manufacturing and especially repairing them can be challenging. Therefore, conical electrodes are generally preferred.

 

The selection of the working surface depends on the pressure applied. A larger working surface is needed when the pressure is high to prevent damage to the electrode end. Therefore, as the thickness of the plate increases, the diameter of the working surface needs to increase. The working surface gradually wears and increases during operation. Therefore, timely repairs are necessary during welding production to prevent a decrease in current density leading to reduced fusion penetration or even no fusion nucleus. Adopting a method where the current automatically increases with the increase in the number of welds can prolong the time between two repairs.

How to Resolve Minor Faults in Intermediate Frequency Spot Welding Machines?

The equipment does not power on: abnormality in machine thyristor, fault in control box P board.

The equipment does not operate after running: insufficient gas pressure, lack of compressed air, abnormal solenoid valve, abnormal operation switch, or controller not powered on, operation of temperature relay.

Cracks appear in welds: excessive oxidation layer on the workpiece surface, high welding current, low electrode pressure, defects in the welded metal, misalignment of the lower electrode, inaccurate equipment adjustment.

Insufficient strength of weld points: insufficient electrode pressure, whether the electrode rod is tightly secured.

Excessive splashing during welding: severe oxidation of electrode head, poor contact of welded parts, whether the adjustment switch is set too high.

Loud noise from welding AC contactor: whether the incoming voltage of the AC contactor during welding is lower than its own release voltage by 300 volts.

Equipment overheats: check water inlet pressure, water flow rate, supply water temperature, whether water cooling is blocked: leo@agerawelder.com