Electromagnetic ultrasonic measuring device for wall thickness of steel tube based on magnetic focusing bridge circuit

Abstract

The invention discloses an electromagnetic ultrasonic measuring device for wall thickness of a steel tube based on a magnetic focusing bridge circuit. The electromagnetic ultrasonic measuring device comprises a through magnetizing coil, magnetic elements, magnetic focusing elements and an electromagnetic ultrasonic detection coil, wherein the magnetizing coil is used to arrange the steel tube to be detected concentrically therein so as to generate a magnetic field distributed in an axial direction after electrification. The magnetic elements are symmetrically arranged outside the magnetizing coil in a plate structure so that the generated magnetic field is distributed in the normal direction of the steel tube. The magnetic focusing elements are respectively arranged on the magnetic elements, and the lower ends of the magnetic focusing elements are close to the outer surface of the steel tube to be detected and maintain a gap. The electromagnetic ultrasonic detection coil is installed in the gap for measuring the wall thickness of the steel tube when a high frequency current is introduced. The invention further discloses other structure types. According to the electromagnetic ultrasonic measuring device for wall thickness of the steel tube based on the magnetic focusing bridge circuit provided by the invention, the radial stable and constant strong magnetic field can be formed in a local position of the steel tube to be detected, and attraction to the steel tube is eliminated by symmetrical arrangement, so that the electromagnetic ultrasonic measuring device for wall thickness of the steel tube is in particular suitable for purposes such as online high speed thickness detection of steel tubes.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic ultrasonic thickness measurement, and more particularly relates to an electromagnetic ultrasonic measurement device for steel pipe wall thickness based on a magnetic gathering bridge. Background technique [0002] Steel pipe wall thickness is one of the important parameters that every steel pipe factory must detect in the production process. The traditional manual measurement method is completed by a caliper or a portable ultrasonic thickness gauge, which has defects such as low efficiency, high labor cost, and large error. For this reason, some research institutions at home and abroad have begun to use water immersion automatic ultrasonic thickness measurement. However, the use of coupling agent, low measurement accuracy and difficulty in applying automatic thickness measurement and high temperature real-time thickness measurement restrict the application of this method in steel pipes. E...

AI Technical Summary

Problems solved by technology

Permanent magnets have been used at home and abroad to provide this magnetic field. Because it is not easy to break the magnetism, the suction force is large, the probe wears quickly, and after a period of work, a large amount of iron filings are absorbed and difficult to clean, which will affect the measurement accuracy; on the other hand, due to the permanent magnet The magnetic force is limited, and the provision of a strong magnetizing field is restricted

Aiming at the above technical problems, CN101706266A discloses a pulsed electromagnet for electromagnetic ultrasonic transducers, wherein a pulsed electromagnet is used to establish a strong magnetic field, however, it is still difficult to obtain a stable signal in automated continuous measurement, which directly affects the to the measurement accuracy, especially in the high-speed measurement environment

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