Disadvantage and defect of resistance welding

Resistance welding is pressed welders parts between the two electrodes, and go through to the current use of resistance heat generated by current flowing through contact with the workpiece surface and the neighboring regions to be heated to the melting or plastic state, so as to form metal-bindingways.

Spot welding, the workpiece is only limited to contact with the surface of the so-called "point" is welded together and form a flat spherical nugget. Spot welding can be divided into a single spot and spot welding. Multi-spot welding, the use of more than two pairs of electrodes, the formation of more than one nugget in the same processes. Seam welding similar spot. Seam welding, the workpiece in two rotating discoid electrode (roll plate) through to form a continuous weld around the lap bar solder joints.

Projection welding is a variant of the spot. Pre-bump in a workpiece. Projection welding, one can form one or more of the nugget in the joints. Butt welding, the workpiece end face contacts are welded after resistance heating and pressure along the entire contact surface.

Electrical resistance welding defects:

1) lack of reliable non-destructive testing, welding to check the quality to rely on technology-destructive testing of specimens and artifacts, as well as by a variety of monitoring techniques to ensure.

2) points, seam welding of lap joints not only increases the weight of the component, and due to the formation of the angle between two plates around the nugget, resulting in lower tensile strength and fatigue strength of the joints.

3) power devices, a higher degree of mechanization and automation, so that the higher equipment costs, maintenance more difficult, and high-power single-phase AC welder is not conducive to the normal operation of the grid. Electrode wear as aerospace, electronics, automotive, household appliances, industrial development, resistance welding together more by the community's attention, at the same time, resistance welding quality also put forward higher requirements.

Weled steel pipe specification, Standard and identification

Welded steel pipe (steel pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding.