摘要
本文通过不同尺寸截面硬质合金产品的侧壁效应程度、不同长度硬质合金棒材的底波反射幅度高低、同一灵敏度下不同规格探头的始波占宽等测试,研究了硬质合金棒材直径和长度、探头的频率等因素对硬质合金棒材内部缺陷检测率的影响规律。利用现有的探头灵敏度测试试块,验证了现有探头的缺陷检测率。研究结果表明,硬质合金棒材直径越小,侧壁效应越明显,缺陷检测率越低;棒材长度越大,反射回波能量越低,缺陷检测率也越低;探头的频率影响棒材内部缺陷检测率;现有探头的缺陷检测率不高,不能满足硬质合金棒材内部质量控制要求。根据硬质合金棒材内部大多数的缺陷方位与棒材检测面成一定夹角的特点,对探头发射波声束线的角度进行了改进,通过比较两种改进探头的脉冲波形及频谱性能,指出了脉冲波形比较平稳、频谱比较窄的改进探头能提高棒材内部缺陷的检测率,并通过实验得以验证。
The side wall effect of cemented carbide products with different section size, the bottom wave reflection amplitude of cemented carbide bar with different length and the initial wave width of the probe with different specification under the same sensitivity were tested. The influences of the factors, such as the diameter and length of the cemented carbide bars, the frequency of the probe, on the defects in the cemented carbide bars, were studied. By using the existing cemented carbide blocks for probe sensitivity test, the defect detection rate of the current probe was verified. The research shows that the smaller the diameter of the cemented carbide bar is, the more obvious the side wall effect is, and the lower the defect detection rate is; The longer the length of the cemented carbide bar is, the lower the reflection echo energy is, and the lower the defect detection rate is. It is confirmed that the defect detection rate of existing probe is low, which cannot meet the requirements of quality control for cemented carbide bars. According to the characteristics that the shape of most defects in cemented carbide bars and the test surface of the bars are include in a certain angle, the emission angle of the probe beam is improved. By comparing with the pulse waveform and spectrum performance of two kinds of improved probe, it is pointed out and confirmed that the relatively stable pulse waveform and relatively narrow spectrum of the improved probe can improve the defect detection rate of cemented carbide bars.
出处
《硬质合金》
CAS
2016年第1期48-54,共7页
Cemented Carbides
关键词
缺陷
检测率
探头
脉冲波形
频谱
defect
detection rate
probe
pulse waveform
spectrum
