Numerical simulation on low-speed magnetic flux leakage inspection to heat exchanger pipes is described. Statistics suggest that 90% of defects in ferromagnetic heat exchanger pipes occur under the retaining plate or nearby, making it a key monitoring area. This paper illustrates influence of different velocities, defect depth and position on the characteristic of flux leakage signals. Result of the numerical simulation provides theoretical principle for application of Magnetic flux leakage (MFL) technique to inspection of heat exchanger pipes. It possesses great significance to enhance the possibility for defect inspection as well.
The magnetic flux leakage (MFL) technique is widely used as a Non-Destructive Testing (NDT) method for welds [1]. Because of the specialty of fillet weld structure, the defect may not be in the location suitably detected, which is normally at the center of yoke poles, and the rate of detect-ability would decline. In this paper, we focus on the yoke-magnetization testing for a fillet weld, and it is studied the influences of air gap between magnetic poles and specimen surface on MFL density at an artificial flaw by Finite Element Method (FEM), and also the influences of distance between magnetic poles and fillet weld on MFL density. The results show that the MFL density observably decreases as the air gap and the distance increase.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.