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45 steel is a common material for parts manufacturing, and it is important to study its thermal damage detection for parts failure assessment.Here, in order to study ultrasonic nonlinear effects of 45 steel with different degrees of thermal damage, specimens with different degrees of thermal damage were made.Ultrasonic nonlinear detection tests were conducted for specimens using the RAM-5000 system made by RITEC company to obtain relation curves between ultrasonic nonlinear coefficients and heating temperature.These curves were deeply analyzed combining with the material’s metallographic microstructure evolution laws.Results showed that the ultrasonic nonlinear coefficient of 45 steel firstly increases, then decreases and increases again with increase in heating temperature;when heating temperature reaches 600 ℃, the ultrasonic nonlinear coefficient begins to increase; when temperature reaches 800 ℃, itreaches the peak value;thenit drops sharply, this is consistent with the coherent strain state of 45 steel between 700-800 ℃; finally, it at 1 300 ℃ rebounds slightly;the correlation between variation of ultrasonic nonlinear coefficient of 45 steel and its metallographic microstructure varying provides atest basis for the ultrasonic nonlinear detection of 45 steel thermal damage and the evaluation of its metallographic microstructure change. 相似文献
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燃油乳化研究和应用的现状 总被引:2,自引:0,他引:2
简单回顾了燃油乳化研究的历程,对燃烧乳化油的节能和降污机理进行了分析,对乳化油制取的方法进行了介绍,展示了乳化油的发展前景。 相似文献
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城市是人口集中分布的地区,人们为各种目的出行十分频繁,行人和车辆的流动方向和数量经常变化,对交通运输的依赖程度较高。交通调查是指通过统计、实测与分析判断,掌握交通状态发展趋势及有关交通现象的工作过程,目的是要找出现状存在的主要问题,从而为问题的合理解决,以及规划提供必要的基础数据,从而使城市交通始终适应城市的发展。本文针对柳州市城市道路交通的发展,运用数理统计的方法,通过对柳州市城中区居民出行方式结构、交通流、路网特性、公共交通客流特性、交通安全、静态交通现状、交通管理现状的调查与分析,找出问题以及产生问题的原因,探讨改善城市交通的途径和解决的方案,从而更好地改善柳州市城中区的现有交通状况。 相似文献