Electromagnetic nondestructive tesing of spheroidization quality based on micromagnetic property

ZHU Shengfeng

(Hangzhou Shibao Auto Steering Gear Co., Ltd, Hangzhou 310018, China)

Abstract: Aiming at solving the problems of taking much time, low efficiency and operating process complex in the detection of spheroidization quality of steering knuckle, a nondestructive detection system of spheroidization quality based on initial magnetic permeability was researched. Through analysed micromagnetic property of ferromagnetic material, an electromagnetic nondestructive detection method based on initial magnetic permeability was put forward. Based on the electromagnetic field theory and basic equations, a mathematical equation among the output induced voltage and the exciting source, parameters of magnetic circuit was established, which was revealed the internal relationship between output quantity and input quantity. A set of detection system of spheroidization quality was designed, and an electromagnetic transducer, a hardware circuit and a software system were analysed, and then the detection system was applied to experimental measurement of the gray cast iron and spheroidal graphite cast iron. The experimental results indicate that the measured value of gray cast iron is about 70% of the measured value of spheroidal graphite cast iron. The method can accurately judge the steering knuckle whether is qualified or not, which can realize online nondestructive testing for the spheroidization quality of steering knuckle.

Key words: initial magnetic permeability; electromagnetic transducer; nondestructive testing; spheroidization quality