超声临界折射纵波定量评定合金钢近表层布氏硬度试验方法的研究

Research on the test method of quantitative evaluating near surface region Brinell hardness of alloy steels by ultrasonic critical refracted longitudinal wave

为了解决合金钢构件布氏硬度无损、在线、在役定量监/检测问题,构建并使用先进临界折射纵波参量试验装置,开展了超声临界折射纵波定量评定合金钢近表层布氏硬度的试验,测量超声临界折射纵波在合金钢标定试件上的传播特性参量,计算评定布氏硬度所需的检测参量,即声速及衰减系数。通过改变收、发探头前沿间距和标定试件的显微织构,观察上述变化对超声波传播特性参量的影响,遴选并评定合金钢标定试件布氏硬度敏感检测参量,建立了临界折射纵波定量评定45#钢标定试件近表层布氏硬度标定映射关系的数学模型,并验证其预测准确度。结果表明,试验所得的临界折射纵波检测参量对标定试件布氏硬度的敏感程度不同,声速与布氏硬度具有较强的关联性,且声速预测模型的测量误差为实际应用的10%,满足要求;而衰减系数不能作为评价合金钢近表层布氏硬度性能的检测参量。本研究为采用超声无损检测方法评定合金钢构件布氏硬度提供了一定的借鉴。

In order to solve the problem of non-destructive,online,and in-service quantitative monitoring/testing of Brinell hardness of alloy steel component,by building and using an advanced critical refractive longitudinal wave parameter testing device,we have carried out experiments on quantitatively evaluating the near surface Brinell hardness of alloy steel using ultrasonic critical refracted longitudinal waves,measured the critical refracted longitudinal wave propagation characteristic parameters in alloy steel calibration specimens,and calculated the detection parameters required for evaluating Brinell hardness,namely acoustic velocity and attenuation coefficient.In the experiment,we altered the front edges distance between the receiving and transmitting probes and the calibrating specimen microstructure,studied the influence of above changes on the ultrasonic propagation characteristic parameters,confirmed the sensitive detecting parameter for evaluating alloy steel calibration specimen Brinell hardness,and finally established the calibration mapping relationship models between the near surface Brinell hardness of 45#steel calibration specimens and the critical refractive longitudinal wave characteristic parameters,verified its hardness prediction accuracy.The test result shows that the wave detection parameters are different in sensitivity to the calibrated specimen Brinell hardness,there is a strong correlation relationship between the acoustic velocity and the Brinell hardness,and the error of the establishing Brinell hardness prediction model is less than 10%.The attenuation coefficient cannot be used to evaluate the near surface Brinell hardness of 45#steel specimens.This study provides some reference for evaluating the Brinell hardness of alloy steel components by ultrasonic non-destructive testing methods.