【作者】 王立勋；

【导师】 梁宏宝；

【作者基本信息】 大庆石油学院 ， 机械电子工程， 2008， 硕士

【摘要】 化工压力容器大多数是在高温、高压、低温、疲劳及腐蚀性介质等苛刻工况下运行,在生产和使用中的失效形式比较复杂,而且随着服役期的延长,由设备内部存在的原始缺陷引发的危险性也在不断增加。要解决化工压力容器的失效分析和预防问题,首先是检测、监控危害性缺陷,超声波技术是高温状态下检测表面、埋藏缺陷最适用的方法,但在使用中由于耦合剂耐热性能、声能衰减、声场特性变异、探头适用性等困难,难以实现对缺陷的有效检测,存在相当一些问题需要研究解决。本文通过试验测量了随着温度的变化(50～450℃范围内),超声波横波在压力容器用钢16MnR钢内的衰减系数,按其趋势拟合了随着温度变化超声横波的衰减变化规律关系式。并对引起超声衰减的两个主要方面,材质衰减和耦合界面造成的声压损失进行讨论分析。在温度超过300℃时,衰减值明显增大,探伤界面的耦合剂界面损失是声波衰减的主要因素。分析了超声波斜探头的声场规律,测量了在50～450℃范围内16MnR钢中超声横波的声速,结合横波声速的变化,得出了超声波斜探头的近场长度、波束指向角的变化规律。由此可知,对于Ф10mm的芯片探头,近场区长度在6～8mm。并且,随着温度的逐渐升高,θ0、θ_上、θ_下都逐渐减小。建立高温环境下焊缝缺陷超声横波检测方法并结合理论进行了工程应用。更多还原

【Abstract】 The chemical industry pressure vessel majority are ruing under the harsh operating modes such as high temperature, high pressure, low temperature, fatigue and corrosiveness medium etc, and the inefficacy form in production and uses is fairly more complicated, and along with lengthening of enlistment period, the dangerous nature is also constantly increasing by what the original defect of existence inside the equipment initiated. To solve failure analysis and the prevention question of chemical industry pressure vessel, and firstly is the checkout and supervising the harmfulness defect, the ultrasonic testing technology is the checkout surface under the high temperature state and lies hidden in the earth the most serviceable method of defect, but owing to the couplant preparation difficulties such as heat tolerance ability, sound energy attenuation, sound field specific property variation and probe applicability etc , being hard to realize to the effectively checkout of defect, and the more suitable questions of existence need to be studied the settlement.This text was measured change ( inside 50 - 450℃’s scopes ) along with the temperature, the attenuation coefficient inside 16MnR’s steel pressure vessel of ultrasonic shear wave by way of the trial,and according to its trend drawing up closing changes the attenuation of ultrasonic shear wave along with the temperature to change the law relation type. And to two major aspects that cause the ultrasonic to weaken, the sound pressure losses that created at material nature attenuation and the coupling interface carries on the discussion to analyze. The attenuation value is clearly enlarged when the temperature surpasses 300℃, and the couplant interface loss detecting a flaw the interface is the major factor that the sound wave is weakend.Analyses the rules of angle probe’s sound field of ultrasonic wave, and measured in 50 - 450℃’s scopes the speed of sound of ultrasonic shear wave in the 16MnR, combines the change of ultrasonic wave speed of sound, reached the rules of the near field length and angle of spread in the angle probe’s of ultrasonic wave .Knowable, the probe chip as forф10mm and near field head of a district’s degree is at 6 - 8mm. And along with going up gradually of temperature,θ0,θ_上andθ_下all reduces gradually.Build under the high temperature environment welding seam defect ultrasonic shear wave checkout method, and combines theory having carried on the engineering applying.更多还原