Study on the characteristics of metal magnetic memory signal of X70 pipeline steel

2011 ◽

Vol 148-149 ◽

pp. 1404-1407

Author(s):

Shu Jun Liu ◽

Zhu Xin Li ◽

Yi Su

Keyword(s):

Pipeline Steel ◽

Magnetic Memory ◽

Memory Testing ◽

Metal Magnetic Memory ◽

Fatigue Load ◽

Cycle Number ◽

Zero Crossing ◽

Tension Load ◽

Fracture Area ◽

Metal Magnetic Memory Testing

To study the relation between stress and the Metal Magnetic Memory Testing (MMMT) signal Hp(y) of ferromagnetic structure, a material mechanics experiment using X60 pipeline steel specimens under tension load and fatigue load is performed. The results show: The value of MMMT signal in elastic stage is small under tension load, while the value of MMMT signal in plastic stage is large. In the process of static tension, the zero crossing point (ZCP) of initial MMMT signal curves shift to the fracture position, and there is only one ZCP of MMMT signal curve at the position of fracture area. In the process of low-load fatigue, the shape and distribution of MMMT signal curves are similar under different cycle numbers of fatigue load. The value of MMMT signal increases a little with the increase of cycle number of fatigue load, and then increases sharply when the specimen is to be fractured. There is only one ZCP of MMMT signal curve at the position of fracture area in the process of fatigue loading.

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Characterizations of damage-induced magnetization for X80 pipeline steel by metal magnetic memory testing

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-160074 ◽

2017 ◽

Vol 54 (1) ◽

pp. 23-35 ◽

Cited By ~ 6

Author(s):

Yunfei Li ◽

Xiangguo Zeng ◽

Liming Wei ◽

Qiang Wan

Keyword(s):

Pipeline Steel ◽

Magnetic Memory ◽

Memory Testing ◽

Metal Magnetic Memory ◽

X80 Pipeline Steel ◽

Metal Magnetic Memory Testing

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Deformation Effects on Metal Magnetic Memory in API 5L X70 Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.2101 ◽

2011 ◽

Vol 415-417 ◽

pp. 2101-2104

Author(s):

Fang Bai ◽

Bo Song

Keyword(s):

Plastic Deformation ◽

Pipeline Steel ◽

Magnetic Method ◽

Magnetic Memory ◽

Stress Effect ◽

Gradient Index ◽

Metal Magnetic Memory ◽

Destructive Testing ◽

Elastic And Plastic Deformation ◽

Api 5L X70 Steel

Metal magnetic memory technology is a passive magnetic method of non-destructive testing based on the residual magnetic field of a ferromagnetic component. The MMM measurements were performed on a series of X70 pipeline steel samples for various values of uniaxial elastic and plastic deformation from zero up to about 20% strain. The outcomes evidence that the metal magnetic memory gradient index m can be used to evaluate the stress-strain state of ferromagnetic materials under tensile stresses. The tensile stress effect on the gradient index m significantly in elastic stage, but the gradient index m remained unchanged in the plastic deformation stage.

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Evolution of the Stress-Induced Residual Magnetic Field of X70 Pipeline Steel With Multiple Corrosion Defects

10.1115/omae2021-62484 ◽

2021 ◽

Author(s):

Sheng Bao ◽

Qiang Luo ◽

Zhengye Zhao ◽

Jian Yang

Keyword(s):

Magnetic Field ◽

Pipeline Steel ◽

Normal Component ◽

Tangential Component ◽

Magnetic Memory ◽

X70 Pipeline Steel ◽

Corrosion Defect ◽

Residual Magnetic Field ◽

Corrosion Defects ◽

Ferromagnetic Steels

Abstract The aim of this research is to investigate the correlation between the residual magnetic field (RMF) and multiple corrosion defects in ferromagnetic steels. Specimens of X70 pipeline steel were machined into standard bars with a single corrosion defect, double corrosion defects and triple corrosion defects, respectively. Tensile tests were carried out to detect the RMF signals on the surface of these specimens. The variations of abnormal magnetic changes of the RMF signals with the external loads were investigated and the results showed that the tangential component and the normal component of the RMF signals of three defect patterns presented different shapes. It was found that the RMF signals were capable of capturing the location and the number of defects in pipeline steels. The peak values of the tangential component and the slopes of the normal component were not influenced by the defects number. This research will promote the investigation on the corrosion defect cluster of ferromagnetic steels based on the metal magnetic memory (MMM) technique.

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