نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشگاه صنعتی نوشیروانی بابل
2 دانشیار گروه مهندسی مواد دانشگاه صنعتی نوشیروانی بابل
3 استاد دانشکده مهندسی مواد و متالورژی دانشگاه علم و صنعت ایران
4 کارشناس ارشد مهندسی مواد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In this paper, the eddy current nondestructive testing method was presented to evaluate the residual austenite in the microstructure and hardness of high chromium cast iron mill balls. For this purpose, some 40 mm high alloy cast iron balls with 30 wt.% Cr and 3 wt.% C nominal composition were selected after sand casting process. To achieve the different hardness and different residual austenite contents in the microstructure, the balls were heat treated at different austenitzing and tempering temperatures. The microstructural studies using by optical and scanning electron microscopies, XRD and Vickers hardness were performed on the samples. Then, the microstructures of the samples were evaluated using an eddy current device at 50 to 200 kHz frequencies. The result showed that, using the eddy current method, different microstructures of the balls with different values of residual austenite and hardness can be identified and separated, rapidly and nondestructively. To the purpose, the eddy current inspection at 150 kHz frequency is selected using the impedance index as a non-destructive evaluation method. This index decreases with increasing residual austenite content.
کلیدواژهها [English]