Abstract
Steel wires are widely used as raw materials for spring valves in engines. Considering the quality and safety issues of their structure, there is a demand to develop nondestructive inspection approaches to detect initial damages in steel. In this study, nonlinear ultrasonic-guided waves generated by an electromagnetic acoustic transducer (EMAT) were used to inspect the defects in steel wires. As one of the noncontact testing methods, the use of EMAT has significant advantages to decrease the nonlinearity induced by instruments and transducer contact condition. The principles of design and manufacturing of EMAT are first introduced. The fundamental theory of nonlinear guided waves is also briefly discussed in this investigation. Phase-matched guided wave modes were generated and measured by using EMAT. Variations of acoustic nonlinearity corresponding to existing defects in specimens were obtained. A scanning electron microscope (SEM) was used to check the existence of microdefects in specimen. The results indicate that the use of EMAT can be an effective means to generate and measure nonlinear ultrasonic-guided waves for inspection of microdefects.
Highlights
Steel wire rods are used as raw materials for various mechanical components
The relative nonlinearity of the fabricated electromagnetic acoustic transducer (EMAT) sensor was measured for each specimen in the longitudinal direction of the steel wire
The analysis of the modes showed that the L1 mode was well implemented for SWOSC-V and SWOCS-VHV, but SWOSC-VHS was able to confirm that the various modes were mixed
Summary
Steel wire rods are used as raw materials for various mechanical components. This research can be applied to the steel wires, raw material of valve springs and have an influence on keeping smooth cycle motion in a gasoline engine. Failure of spring valves may occur before expectation of fatigue failure. We need a reliable method for steel wires that can evaluate microdefects or early stage damage detection. For the research work related with this study not so many articles were published. Gao et al developed nondestructive evaluation (NDE)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
