High-frequency induction welding
In high-frequency contact welding and high-frequency induction welding, the equipment that provides current and the equipment that provides squeezing force are independent of each other. In addition, both methods can use a magnetic rod, which is a soft magnetic element placed inside the tube body, which helps to converge the welding flow at the edge of the steel strip.
In both cases, after the steel strip is cut and cleaned, it is rolled up and sent to the welding point. In addition, a coolant is used to cool the induction coil used in the heating process. Finally, some coolant will be used in the extrusion process. Here, a lot of force is applied to the squeeze pulley to avoid porosity in the welding area; however, using a larger squeeze force will result in an increase in burrs (or weld beads). Therefore, specially designed cutters are used to remove burrs inside and outside the pipe.
The main advantage of the high-frequency welding process is that it can process steel pipes at high speeds. However, a typical situation in most solid-phase forging joints is that it is not easy to reliably test the joints of high-frequency welding if traditional non-destructive technology (NDT) is used. Welding cracks may appear in flat and thin areas of low-strength joints. Such cracks cannot be detected using traditional methods, and therefore may lack reliability in some demanding automotive applications.
Gas Tungsten Arc Welding (GTAW)
Traditionally, steel pipe manufacturers choose to complete the welding process with gas tungsten arc welding (GTAW). GTAW creates an electric welding arc between two non-consumable tungsten electrodes. At the same time, inert shielding gas is introduced from the spray gun to shield the electrode, generate ionized plasma flow, and protect the molten weld pool. This is an established and understood process, and it will be repeatable to complete a high-quality welding process.
The advantages of this process are repeatability, no spatters during welding and the elimination of porosity. GTAW is considered to be an electrical conduction process, so, relatively speaking, the process is relatively slow.
Post time: Nov-21-2023