Advantages and disadvantages of the electric resistance welding

The electric resistance welding (ERW) is a kind of welding method, which uses the resistance heat generated by the current passing through the welding piece and the contact place as a heat source to heat the piece locally, and at the same time to weld under pressure. There are four main methods of resistance welding: spot welding, seam welding, projection welding, butt welding.

API 5L ERW steel pipes

API 5L ERW steel pipes

Advantages of the electric resistance welding:

  1. When the molten core is formed, it is always surrounded by a plastic ring, and the molten metal is isolated from the air, so the metallurgical process is simple.
  2. The heating time is short and the heat is concentrated, so the heat-affected area is small, and the deformation and stress are also small. It is usually not necessary to arrange correction and heat treatment procedures after welding.
  3. There is no need for filler metals such as welding wire and electrode, as well as welding materials such as oxygen, acetylene and hydrogen, so the welding cost is low.
  4. Simple operation, easy to achieve mechanization and automation, improved working conditions.
  5. High productivity, and no noise and harmful gas, can adapt to mass production.
ERW steel pipes

ERW steel pipes

Disadvantages of the electric resistance welding:

  1. At present, there is still a lack of reliable non-destructive testing methods, and the welding quality can only be checked by the destructive test of process samples and workpiece, as well as by various monitoring technologies.
  2. The point-and-seam welded lap joints not only increase the weight of the members, but also lower the tensile strength and fatigue strength of the joints due to the Angle formed around the weld nugget of the two plates.
  3. The equipment has high power, high equipment cost and difficult maintenance, and the commonly used high-power single-phase ac welder is not conducive to the balanced operation of the power grid.

In Hebei Haihao Group, the electric resistance welding is widely used in the production of flanges, pipe fittings and other pipeline products, with mature technology and great