钢中非金属夹杂物对时频域超声参量的影响

Effect of embedded inclusion in steel on ultrasonic parameters in time frequency domain

通过建立包含夹杂物的二维金属板超声测量数值分析模型,研究超声信号随夹杂物的深度、厚度和类型等属性特征的变化规律,并通过超声显微镜和扫描电镜实验验证模型的有效性。研究结果表明:纵波声速随夹杂物厚度的增加呈线性递增,含有Al2O3夹杂物的声速最大且增速最快,含有MnS夹杂物的声速最小且增速最慢,纵波声速可以作为判定内部是否存在夹杂物的参量;不同超声参量随入射波长的变化关系曲线,可用于判定夹杂物的厚度;当夹杂物深度位于钢板厚度的中间时,衰减系数最大,且含有MnS夹杂物引起的声波幅值衰减最严重,含有TiN夹杂物的声波幅值衰减最小。

A numerical analytical model of two-dimensional isotropic plate with embedded inclusion was established,and the variation of ultrasonic signals with the depth,thickness and type of inclusions was studied.The validity of the model was verified using experimental results from ultrasonic microscope measurement and scanning electron microscope.The results show that the longitude sound velocity increases linearly with the thickness of inclusion.The Al2O3 inclusion has the largest sound velocity and the fastest increasing rate,while the sound velocity of MnS inclusion has the smallest sound velocity and the slowest rising rate.The longitudinal sound velocity can be used to determine the existence of inclusion.The relationship between different ultrasonic parameters and incident wavelength can be used to determine the thickness of inclusions.When the inclusion is at the center of the steel plate,the attenuation coefficient has the maximum value,and the attenuation of MnS inclusion is the maximum,while the attenuation of TiN inclusion is the minimum.