摘要
目的 研究一种适合于无负载条件下灵敏检测疲劳构件中闭合裂纹的超声技术。方法 采用入射角度不同的超声纵波,对30CrMsi钢试样表面上1.5～8mm范围的开口及闭合裂纹进行检测实验。通过入射角与底面回波幅度、回波曲线形状、裂纹尺寸间的关系获得对裂纹具有灵敏反应的超声波最佳入射角。结果 小角度入射纵波较垂直入射或大角度入射纵波均具有较高的灵敏度;尤其当入射角在2°附近,具有最高检测灵敏度。结论 采用小角度纵波技术,可提高超声对疲劳小裂纹的反应。只要入射角度合适,检出卸载后构件中的闭合裂纹也是可能的,但对闭合裂纹的定量仍有困难。
AimTo develop a ultrasonic method for sensitive evaluation of fatigue cracks on the unloading componentparts.MethodsExperiments are based on the samples of 30 CrMsiA. The cracks are vertical with the surface of samples and in depth of 1.5mm～8mm. The optimal angle incidence can be got from the relation of angle incidence. echo wave's scope and shape.ResultsSmall angle incidence longitudinal wave has higher sensitivity than normally or big angle incident wave. Especially, it has the highest sensitivity hearby 2°whether crack is open or close.ConclusionA small angle incidence longitudinal wave can enhance the sensitivity of ultrasonic to small fatigue cracks.Detecting out close cracks is possible.However, it is still difficult to size them.
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2004年第1期39-43,共5页
Journal of Northwest University（Natural Science Edition）
基金
国家自然科学基金资助项目(39870467)
关键词
小角度
纵波
开口裂纹
闭合裂纹
灵敏度
small angle beam
longitudinal wave
open crack
close crack
sensitivity
