Eddy Current Inspection Technology for Welding Seam Testing

By detecting and remedying defects in welds during the early stages of product manufacturing, production costs can be reduced, customer investment required for return can be lowered, and product lifespan can be extended. Eddy current non-destructive testing is a reliable, fast, and economical way to accomplish preventative maintenance of products and ensure their safety performance.

Ⅰ. 5 advantages of eddy current inspection

1. During testing, the coil does not need to make contact with the object being tested, nor does it need a coupling medium, resulting in fast testing.

2. It has high sensitivity for detecting defects on or near the surface of the object being tested, and has good linear indication within a certain range, making it useful for quality management and control.

3. It can be used to test objects in high-temperature environments, narrow areas, or deep hole walls (including pipe walls).

4. It can measure the thickness of metal or non-metal coatings.

5. The testing signal is an electrical signal that can be digitally processed, making it easy to store, reproduce, compare, and analyze data.

Ⅱ. 2 applications of eddy current inspection

1. Power and Petrochemical Industries

Eddy current inspection is used for in-service and pre-service testing of non-ferrous and ferrous metal pipelines (such as copper pipes, titanium pipes, stainless steel pipes, and boiler pipes) in power stations (thermal power plants, nuclear power plants) and petrochemicals (oil fields, refineries, chemical plants).

It can reliably detect intergranular corrosion, wall thickness reduction, and outer wall wear, and effectively remove interference signals from support beams and tubesheet during testing.

In addition, eddy current inspection is used to test components such as the center hole of large turbine shafts, engine blades, pump rods, drill rods, bolts, and screw holes. Acoustic pulse testing technology can be used for fast testing of various metal or non-metallic pipelines. Metal magnetic memory technology is used for diagnosing early damage to ferromagnetic parts of in-service equipment.

2. Metallurgy and Machinery

Eddy current inspection is used for online and offline testing of various metal pipes, rods, wires, and threaded rods. During testing, long defects such as longitudinal cracks and gradual changes can be simultaneously detected, and short defects such as through-holes can be detected effectively. It also effectively suppresses certain interference signals (such as material unevenness and shaking) during online and offline testing of pipelines, and has high sensitivity for detecting defects on both the inside and outside walls of metal pipelines. It can also be used for mixing and sorting of mechanical parts, evaluation of carburizing depth and heat treatment state, and hardness measurement, among other things.