What is Resistance Seam Welding?

May be there are many people know ERW steel pipe, but there are less people know much information of electric resistance welding. Several days ago, pipe manufacturer Great Steel Pipe shared some information of that, such as spot welding. Today, we will continue this topic, Prime Steel Pipe will share the resistance seam welding for all of you. Resistance seam welding is a process that produces a weld at the faying surfaces of two similar metals. The seam may be a butt joint or an overlap joint and is usually an automated process. Resistance seam welding is different from butt welding and spot welding. Butt welding typically welds the entire joint at once and seam welding forms the weld progressively, starting at one end. It is the same as spot welding, seam welding relies on two electrodes, usually made from copper, to apply pressure and current. Resistance seam welding use a rotating disc-shaped electrode. It can pressurize, energize and drive the workpiece forward, forming a series of solder joints. Weld requirements sealed, the solder joints overlap more than 30%. Thickness is generally below 2 mm, welding speed of about 0.5 to 3 m / min.

The welding current may be continuous or intermittent. A transformer supplies energy to the weld joint in the form of low voltage, high current AC power. The joint of the work piece has high electrical resistance relative to the rest of the circuit and is heated to its melting point by the current. The semi-molten surfaces are pressed together by the welding pressure that creates a fusion bond, resulting in a uniformly welded structure. Most seam welders use water cooling through the electrode, transformer and controller assemblies due to the heat generated.

There are two modes for seam welding: Intermittent and continuous. In intermittent seam welding, the wheels advance to the desired position and stop to make each weld. This process continues until the desired length of the weld is reached. In continuous seam welding, the wheels continue to roll as each weld is made. Sewing is mainly used for straight, ring or round welds, such as fuel tanks, cylinders, jet flames and shells and mounting edges. Seam welding produces an extremely durable weld because the joint is forged due to the heat and pressure applied. A common use of seam welding is during the manufacture of round or rectangular steel tubing, such as ERW steel pipe.