Search

Abstract: Numerous machine components are constantly subject to different magnetic fields mainly due to the environments they are in, and they show some wear process throughout their life time. To understand this wear process better, the effect of magnetic field on the tribological properties of AISI 4140 steel has been investigated by applying different magnetic field intensities. One of the important factors affecting the wear and friction properties of a tribological system is wear debris and their properties like chemical structure and movement between mating bodies. For this respect, magnetic field was applied on a ferromagnetic material both before and during wear tests. Then, tribological properties of the samples magnetized before the wear tests were compared with the samples to which magnetic field was applied during the tests. It was observed that samples subjected to the magnetic field during tests showed better wear resistance and lower friction coefficient values than the others as the magnetized wear debris produced during test could be removed between mating bodies by means of magnetic effect while oxidized debris were held at the rubbing interface and lowered the debris production. [Copyright &y& Elsevier]

Abstract: For investigating the magnetic abnormality influenced by stress in ferromagnetic materials, static tension tests on a case-hardened steel were carried out. Different loads, which covered tensile elastic loads up to plastic deformation and break, were applied. Meanwhile, the normal component of magnetic flux leakage, H p(y), was measured by metal magnetic memory testing. The results indicate that H p(y) values change with the tensile loads and positions. There exists a relationship between k, which is the inclination of the linear amplitude-locus magnetic flux leakage curve, and static tension load. A simple model is derived. Additionally, the mechanism of the magnetic memory effect can be explained by the theory of the interaction between dislocations and domains. The research provides the potential possibility of quantitative inspection for metal magnetic memory testing. [Copyright &y& Elsevier]

In this paper, stress and fatigue-loaded ferromagnetic steel samples were evaluated using three different remanent flux leakage transducers. Giant magnetoresistive sensors were used as the pickup elements. Each transducer has its own integrated local magnetizing section, which allows us to magnetize the tested material in different directions. The defect detection dependency on angle, at which it occurs to the magnetizing field and sensing element, is minimized by gathering and then integrating the information from transducers. The performance of the transducers was verified using a steel plate (S355J2G3) with electro-discharge machined notches. Further experiments were carried out using fatigue and stress-loaded steel samples. [ABSTRACT FROM AUTHOR]