35MnB合金淬硬层深度的超声无损测量  

Ultrasonic nondestructive testing for the hardened layer depth of induction quenched 35MnB alloy

作　　者：付磊 韩军 龙晋桓 王愉锦 Fu Lei;Han Jun;Long Jinhuan;Wang Yujin(School of Advanced Manufacturing,Fuzhou University,Quanzhou 362000,China;Quanzhou Institute of Equipment Manufacturing,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Quanzhou 362000,China;University of Chinese Academy of Sciences,Beijing 100000,China)

机构地区：[1]福州大学先进制造学院,泉州362000 [2]中国科学院福建物质结构研究所,泉州装备制造研究中心,泉州362000 [3]中国科学院大学,北京100000

出　　处：《电子测量与仪器学报》2022年第11期24-32,共9页Journal of Electronic Measurement and Instrumentation

基　　金：中国科学院对外重点合作项目(121836KYSB20180062);科技厅-福建省中科院STS计划配套项目(2021T3060);泉州市科技计划项目(2021C063L)资助。

摘　　要：针对过渡层较大的感应淬火零件用超声法测量淬硬层深度时,极限硬度点难以准确定位的问题,开展35MnB合金淬硬件的淬硬层深度超声测量实验。用小波多分辨率分析(MRA)研究信号在不同分解尺度下的时频特征,分析信号在各频带的能量分布,并探求提取背散射信号的趋势特征计算淬硬层深度的方法。结果表明,背散射信号中的高频振动成分明显,分布无规律且能量较低;趋势特征项随信号振动幅值包络缓慢变化,能量占比高达96.73%,显著高于其他分解项,高尺度分解下的MRA过程实质上滤除了多数与淬硬层深度信息无关的杂波噪声项。基于趋势特征项的实测结果最大平均误差为0.123 mm,最大重复误差为6.24%,测量精度以及重复可靠性均显著高于常规超声测量模型,相比于金相法和显微硬度法具有更高效、无损等优势,在工程机械零件的实际测量中具有较好的应用前景。The hardened layer depth(HLD) of metal parts is one of the important factors to determine its wear resistance and fatigue strength. Ultrasonic backscatter method can realize nondestructive testing for HLD. However, for those induction hardened parts with large transition layer, it is difficult to accurately locate the limit hardness point, which leads to inaccurate testing results. In this work, HLD measurement experiments of induction quenched 35MnB alloy were carried out. The wavelet multi-resolution analysis(MRA) was employed to find the characteristics of the time-frequency domain of ultrasonic backscattering signals at different decompsosition scales. The energy distribution in each frequency band was analyzed, and the trend characteristics of ultrasonic backscattering signals were extracted to locate the limit hardness point in transition layer of the induction quenched samples. The result shows that the original backscattering signals contain obvious rapidly-oscillating components with low energy and irregular distribution. The signal trend varies slowly with the amplitude of the oscillation with energy portion as high as 96.73%, which is significantly higher than other decomposition terms. The MRA process essentially filters out most of the clutter noise components irrelative to the depth information of the hardened layer. The actual measurement result shows that the maximum average error of this method is 0.123 mm, the maximum repeatability error is 6.24%, showing that the present method achieves high accuracy and repetitive reliability. Compared with metallography and microhardness, this method is more efficient and nondestructive, which shows a good practical application prospect.

关 键 词：35MnB合金 淬硬层深度 超声检测 背散射信号 小波多分辨率分析 信号趋势特征 

分 类 号：TB553[理学—物理]