Variation regularity of metal magnetic memory signals with inspecting time-interval and location
Chun-yan Yan , Wu-shen Li , Xin-jie Di , Zhen-kui Xue , Shi-wu Bai , Fang-ming Liu
Journal of Central South University ›› 2007, Vol. 14 ›› Issue (3) : 319 -323.
Variation regularity of metal magnetic memory signals with inspecting time-interval and location
Influences of inspecting time-interval and location on varying behavior of metal magnetic memory (MMM) signals of defects were studied. Different areas in two precracked weldments were inspected at different time-intervals by type TSC-1M-4 stress-concentration magnetic inspector to obtain MMM signals. Mechanisms of MMM signals varying behavior with inspecting time and space were analyzed and discussed respectively. It is found that MMM signals don’t change with inspecting time-interval, since stress field and magnetic leakage field maintain unchanged at any time after welding. On the other hand, MMM signals differ greatly for different inspecting locations, because stress field and magnetic leakage field are unevenly distributed in defective ferromagnetic materials.
nondestructive testing / metal magnetic memory / inspecting interval / inspecting location
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