Research on Controlled Jet Ultrasonic Inspection Method for LZ50 Hot Rolled Large Steel Bars

Abstract

Ultrasonic inspection is the main method of on-line inspection for large size steel bars. For maximum Φ 600 mm in diameter, single maximum length up to 10 m of LZ50 hot rolled steel bar, to meet the requirement of the on-line inspection efficiency and precision at the same time, adopting controlled jet method that the probe and the workpiece is non-contact, coupled with one certain length water body, and its comprehensive inspection ability is stronger. In the application process of controlled jet method, the self-developed jet coupling module and the zonal inspection technology are used to effectively suppress the turbulence noise and structure echo. The test results show that under the premise of signal-to-noise ratio (SNR) not less than 8 dB, the controlled jet method can effectively identify Φ 3.0 mm artificial flat bottom hole of 5 mm and 300 mm in depth, and verify the effectiveness of the controlled jet method.