Material Evaluation of the Strenght and Degradation of Ally Steels by Magnetic Barkhausen Noise Analysis

“巴克豪森噪声分析法”是一种先进的磁性无损测量技术，它是为了评定铁磁材料的强度和表征其微观结构特性而发展起来的。巴克豪森噪声测量系统由巴克豪森噪声分析装置和位于磁化铁心磁极中心的小测量线圈的磁感应电压积分电路组成。从磁化电流（Hs）对.测量电压（Bs），如果能够在比BHN测量更宽的范围内评估应力水平。其次，进行了BHN分析，以检测（1）疲劳轧辊材料的损伤过程，（2）用数字频谱分析仪检测Cr-Mo合金钢的劣化。FFT谱的明显差异是recobnized为viegin和使用的材料。此外，BHN还可以评价焊接件的残余应力和石墨铸铁的性能。因此，研制的混合型BHN测量系统可以同时提供铁磁材料强度特性的两个信息，即“应力状态”和“微观结构质量”。似乎有多种可能性进行更广泛和多边的材料评价。

Advanced magnetic non-destructive measurement technique, "Barkhausen noise (BHN) analysis" method is developed for ecaluating the strength and characterizing the mictostructural properties of ferromagnetic materials Thie BHN measuring system consists of the devices for analyzing BHN and circuit for integrating magnetic induced voltage of small measuring coil located in the center of magnetizing core poles. Taking a parameter of the slope, (apparent permeability) from the loop of magnetizing current(Hs) v.s. measuring voltage(Bs), if enables to evaluate the stress level in more wider tange then BHN measurement. Next, BHN analysis is performed to detect (1) the damaging process in fatigued roller material,(2) the degradation of Cr-Mo alloy steels by digital spectrum analyzer. Distinct differences in FFT spectrum are recobnized for the viegin and used material. Moreover, residual stresses in the welded component and the property of graphite cast iron are also able to be evaluated by BHN. In consequence, the developed hybrid-type BHN measuring system can provide us simultaneously the two informations about the properties of material stength, namely, "stress state" as wsell as "microstructural quality" of ferromagnetic materials. Is seems to have the various possibility for mowe wide and multilateral matireal evaluation.