Introduction
Underbalanced Direct Current Resistance (DC) welding is a unique joining technique that utilizes electric current to locally heat a workpiece material. The electrical current is passed through the assembly, heating the surface of the material to its melting temperature. The component pieces of the assembly are then fused together upon cooling. The main characteristic of this welding method is that it employs an exceptionally low voltage in order to produce a minimal amount of heat. This allows the joint zone to produce a strong bond between materials with minimal distortion. In order to maximize the results of this welding process, there are several engineering parameters which are required to be properly adjusted. One such parameter is the recommended voltage and current settings based upon the material being used. In the case of Underbalanced DC welding, the recommended values of voltage and current settings depend upon the carbon content of the material.
Carbon Content
Carbon is one of the primary components of all steels and alloys. It is both light and strong, and it is also highly conductive to electricity. The addition of carbon to a steel material increases its strength and its resistance to wear, as well as its resistance to general corrosion. Generally, the higher the carbon content of the material, the higher its strength and wear resistance will be. However, it should be noted that the carbon content of the material can also affect the voltage and current settings of the welding process.
Voltage and Current Settings
For Underbalanced DC welding, the recommended voltage and current settings should be adjusted according to the carbon content of the material. Basically, the higher the carbon content of the material, the higher the recommended voltage and current settings for welding operations. As a general rule, for low carbon content alloys (less than 0.15%), the recommended voltage should be between 20 and 25 volts, and the recommended current should be between 1.2 and 1.5 amps. For steels with a higher carbon content (more than 0.15%), the recommended voltage should be between 20 and 30 volts, and the recommended current should be between 1.5 and 2 amps.
Wire Feed Speed
In addition to the voltage and current settings, the wire feed speed should also be adjusted according to the carbon content of the material. Again, the higher the carbon content of the material, the higher the recommended wire feed speed. Generally, for steels with a low carbon content (less than 0.15%), the recommended wire feed speed should be between 2 and 5 meters per minute (20 and 50 feet per minute). For steels with a higher carbon content (more than 0.15%), the recommended wire feed speed should be between 5 and 8 meters per minute (50 and 80 feet per minute).
Conclusion
Underbalanced DC welding is a unique joining technique that utilizes electric current to locally heat a workpiece material, thereby producing a strong and reliable bond between components. In order to get the best results from this process, it is important that the recommended voltage and current settings be adjusted according to the carbon content of the material being used. Higher carbon content materials require higher voltage and current settings. Additionally, the wire feed speed should also be adjusted according to the carbon content of the material. Higher carbon content materials require higher wire feed speed. Overall, it is important to properly adjust these parameters in order to get the best results from the Underbalanced DC welding process.
