DC (direct current) magnetization probe based on transceiving type coil suitable for omega weld

Abstract

The invention relates to the technical field of electromagnetic nondestructive testing for a seal weld of a control rod driving mechanism of a nuclear power station, and specifically discloses a DC (direct current) magnetization probe based on a transceiving type coil suitable for an omega weld. The probe comprises a DC magnetic saturation unit group, a spool-type Bobbin exciting coil and a densely covered detection sensor group, wherein the DC magnetic saturation unit group and the spool-type Bobbin exciting coil jointly form an 'H'-shaped frame structure; a left vertical structure wound coil and a right vertical structure wound coil form the DC magnetic saturation unit group; a Bobbin exciting coil is wound on a middle axial framework, so as to form the spool-type Bobbin exciting coil; the DC magnetic saturation unit group and the spool-type Bobbin exciting coil integrally cross above the weld in an omega weld detection zone; the densely covered detection sensor group comprising a plurality of point sensors is mounted on a cambered surface of the weld in the omega weld detection zone. The probe has the advantages that the detected depth range is wider, the quantitative ability is enhanced, and the defect locating capability can be improved by gluing a densely covered sensor detection unit group on the cambered surface of the weld.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic non-destructive testing of sealed weld seams of control rod drive mechanisms of nuclear power plants, and in particular relates to a DC magnetization probe suitable for Ω weld seams based on transceiving coils. Background technique [0002] The Ω weld is the connection sealing weld between the reactor control rod drive mechanism and the cup seat of the reactor top cover. It is a special sealing weld at the pressure boundary of the primary circuit. The role of the primary circuit medium (boric acid water), especially the temperature change during shutdown and startup will promote the expansion of welding defects inside the weld, which is the weak link of the nuclear primary components. The inner ring of the Ω weld base metal is 0Cr18Ni12Mo2Ti, the filler material is 0Cr18Ni9Ti, the structure of the heat affected zone of the base metal and the weld is ferrite + austenite, the grain size is 6...

AI Technical Summary

Problems solved by technology

In this case, the surface of the outer surface that can be well contacted by the transducer is small, which brings problems such as large surface lift-off effect and insufficient penetration depth to the eddy current test.

For the eddy current testing of welds with this special structure, the design of the transducer is very important. A lot of research has been carried out at this stage, including the arrangement of multiple point-type, orthogonal, and differential The structure of the same coil, but most of them adopt the signal excitation and reception mode based on self-sending and self-receiving. This mode has the characteristics of simple design and simple coil layout, but due to the background noise of the weld area and the And the weak magnetism in the base metal area has a great impact on the resolution and detection of signals, and sometimes it is even difficult to detect

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