Characterization of Crack Initiation Life in Ferromagnetic Material by Metal Magnetic Memory Testing

2015 ◽  
Vol 817 ◽  
pp. 791-796
Author(s):  
Chang Liang Shi ◽  
Wei Xue Tang ◽  
Hao Zhan ◽  
Shi Yun Dong
Keyword(s):  
Magnetic Field ◽  
Crack Initiation ◽  
Normal Component ◽  
Ferromagnetic Material ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Numerical Fitting ◽  
Crack Initiation Life ◽  
Metal Magnetic Memory Testing

In the geomagnetic field, stress can induce spontaneous magnetic signals in ferromagnetic materials, the method, named metal magnetic memory testing, can be potentially applied in estimating the fatigue life. In this paper, the normal component of magnetic field, Hp (y), was measured during dynamic tension test on the surfaces of ferromagnetic specimens with stress concentration factor of 5. The results indicated that the gradient of magnetic field intensity, K, was the key parameter to characterize crack initiation life. Then the numerical fitting of K and fatigue cycles were done under three level loads, 568.7MPa, 698.8MPa and 864.4MPa, meanwhile, a simple model was derived.

scholarly journals Application of Metal Magnetic Memory Testing Technology to the Detection of Stress Corrosion Defect

2020 ◽  
Vol 10 (20) ◽  
pp. 7083
Author(s):  
Bingxun Zhao ◽  
Kai Yao ◽  
Libo Wu ◽  
Xinglong Li ◽  
Yue-Sheng Wang
Keyword(s):  
Stress Corrosion ◽  
Normal Component ◽  
Ferromagnetic Materials ◽  
Error Rates ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Corrosion Defect ◽  
Detection Of Stress ◽  
Metal Magnetic Memory Testing

The damage of equipment manufactured with ferromagnetic materials in service can be effectively detected by Metal Magnetic Memory Testing (MMMT) technology, which has received extensive attention in various industry fields. The effect of stress or strain on Magnetic Flux Leakage (MFL) signals of ferromagnetic materials has been researched by many scholars for assessing stress concentration and fatigue damage. However, there is still a lack of research on the detection of stress corrosion damage of ferromagnetic materials by MMMT technology. In this paper, the electrochemical corrosion system was designed for corrosion experiments, and three different experiments were performed to study the effect of corrosion on MFL signals. The distribution of MFL signals on the surface of the specimen was investigated. The results indicated that both the normal component Hn and tangential component Ht of MFL signals presented different signal characteristics when the specimen was subjected to different working conditions. Finally, two characterization parameters, Sn and St, were defined to evaluate the corrosion degree of the specimen, and St is better. The direct dependence of corrosion depth on the parameter was developed and the average error rates between the predicted and measured values are 8.94% under the same working condition. Therefore, the expression can be used to evaluate the corrosion degree of the specimen quantitatively. The results are significant for detecting and assessing the corrosion defect of ferromagnetic materials.

Characterization of Fatigue Damage of Crankshaft Remanufacturing Core by Two-Dimensional Magnetic Memory Signal

2012 ◽  
Vol 538-541 ◽  
pp. 1588-1593 ◽  
Author(s):  
Nan Xue ◽  
Li Hong Dong ◽  
Bin Shi Xu ◽  
Cheng Chen ◽  
Shi Yun Dong
Keyword(s):  
Fatigue Test ◽  
Fatigue Damage ◽  
Normal Component ◽  
Stray Field ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Two Dimensional ◽  
Metal Magnetic Memory ◽  
Bending Fatigue ◽  
Metal Magnetic Memory Testing

Fatigue damage degree of crankshaft remanufacturing core was studied based on Metal Magnetic Memory Testing. Bending fatigue test of crankshaft remanufacturing core was conducted on the resonant fatigue test rig and variations of two-dimensional magnetic memory signal distribution in crankshaft pin fillets were studied at different bending fatigue cycle. Experimental research shows that distributions of Hp(x) signals, namely, tangential component of spontaneous stray field and Hp(y) signals, namely, normal component of spontaneous stray field in crankshaft pin fillets have no obvious change with loading cycle when no crack initiation and propagation occur in crankshaft pin fillets. Characteristics of Hp(x) and Hp(y) signal both show dynamic variations when crack in crankshaft pin fillets initiates and extends at medium rate or high rate. Metal Magnetic Memory Testing is a dynamic method for monitoring fatigue crack propagation in crankshaft.

Research on the Attenuation Law of Metal Magnetic Memory Testing Signal

2014 ◽  
Vol 668-669 ◽  
pp. 981-984
Author(s):  
Yuan Liang Zhang ◽  
Yan Lv ◽  
Hao Zhang ◽  
Jin Long Wang ◽  
Gui Jie Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Static Tension ◽  
Metal Magnetic Memory ◽  
Surface Magnetic Field ◽  
Signal Value ◽  
Testing Signal ◽  
Metal Magnetic Memory Testing ◽  
Normal Magnetic Field

In order to clear the timeliness issues of metal magnetic memory signal value after unloading, we conduct some static tension experiments on some specimens in materials of KMN, which is commonly used in centrifugal compressors? Furthermore, we analyze the specimen, which is prefabricated artificial defects, on the surface normal magnetic field strength decay law with EMS-2003, the intelligent magnetic memory tester. The results show that: the surface magnetic field signal value is reduced by time after unloading, in other words it has certain timeliness.

scholarly journals Stress measurement using magnetic Barkhausen noise and metal magnetic memory testing

2010 ◽  
Vol 21 (5) ◽  
pp. 055703 ◽  
Author(s):  
Ping Wang ◽  
Shougao Zhu ◽  
Gui Yun Tian ◽  
Haitao Wang ◽  
John Wilson ◽  
...  
Keyword(s):  
Stress Measurement ◽  
Barkhausen Noise ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Magnetic Barkhausen Noise ◽  
Metal Magnetic Memory Testing

Magnetic crawler climbing detection robot basing on metal magnetic memory testing technology

2020 ◽  
Vol 125 ◽  
pp. 103439 ◽  
Author(s):  
Fumin Gao ◽  
JianChun Fan ◽  
Laibin Zhang ◽  
Jiankang Jiang ◽  
Shoujie He
Keyword(s):  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Testing Technology ◽  
Metal Magnetic Memory Testing

scholarly journals Characteristics of Metal Magnetic Memory Testing of 35CrMo Steel during Fatigue Loading

Metals ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 119 ◽  
Author(s):  
Zhibin Hu ◽  
Jianchun Fan ◽  
Shengnan Wu ◽  
Haoyuan Dai ◽  
Shujie Liu
Keyword(s):  
Fatigue Loading ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
35Crmo Steel ◽  
Metal Magnetic Memory Testing

Eddy Current and Metal Magnetic Memory Testing Nondestructive Evaluation for Superficial Defects of Old Cylinder Barrel

2016 ◽  
Vol 850 ◽  
pp. 107-112
Author(s):  
Chang Liang Shi ◽  
Shi Yun Dong ◽  
Wei Xue Tang ◽  
Hao Zhan
Keyword(s):  
Stress Concentration ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Current Testing ◽  
Cylinder Barrel ◽  
Metal Magnetic Memory Testing

Eddy current testing and metal magnetic memory testing, cooperated with special testing devices, were applied to detect the superficial defects of old cylinder barrel. It was indicated that there were three types of the signals, which were non-defect signals, discontinuous peak signals and continuous peak signals. Non-defect signals indicated that there was no defect in cylinder barrel, and the discontinuous peak signals denoted that there was circumferential cracking, and the continuous peak signals showed that there was longitudinal cracking in the surface of cylinder barrel. The amplitude of eddy current testing signals characterizes the depth of cracking, and the gradient of magnetic signals descript the degree of stress concentration. The method mentioned above detects the cracking and stress concentration in the superficial coat of old cylinder barrel, which effectively guarantee the quality of automobile cylinder.

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