导　　师： 关卫和

学科专业： 080706

授予学位： 硕士

作　　者： ;

机构地区： 浙江工业大学

摘　　要： 在高温高压条件下,化工行业、石油炼制、石油化工、煤化工等某些临氢设备容易受到氢的侵蚀。其中高温氢腐蚀是典型的损伤之一,它的危害性很大,严重影响到设备的安全运行,对人民生命财产安全造成了很大的威胁。 本文结合前期本小组高温氢腐蚀试验的研究成果,将20号钢和Q345R两种材料的试块置于450℃、18MPa的氢分压环境下充氢18小时,通过超声波衍射时差法/(Time of flight diffraction, TOFD/).波速比法、测厚法等超声检测的方法结合宏观检测,微观金相组织观察,硬度测试来对氢腐蚀程度进行表征和评价,并与充氢36小时和80小时试验的数据进行比较,总结出腐蚀程度与充氢时间的关系,提出利用超声的方法来对高温氢腐蚀进行检测,并将该方法运用到工程实际中。 研究结果表明： /(1/)试样在经过18小时、36小时、80小时腐蚀后,试样经历了表面从几无变化、出现密集鼓泡、出现裂纹的过程,腐蚀程度逐步加深。 /(2/)随腐蚀时间增加,试样依次出现表面脱碳、近表面完全脱碳、晶界上显微裂纹。 /(3/)充氢时间越长,材料性能下降越大,硬度值降低越明显。 /(4/)试样在腐蚀后均出现“增厚”现象,随着充氢时间的延长,腐蚀程度不断加重。 /(5/)随着充氢时间的延长,横纵波波速比不断升高。充氢18小时后波速比变化不大,在氢腐蚀的早期阶段；充氢36小时后的波速比数值超过了0.55,材料已经发生了氢腐蚀；充氢80小时后波速比在0.57左右,腐蚀程度进一步加深。 /(6/)发生氢腐蚀后,TOFD扫描直通波发生了时间延迟,纵波的声速变慢,通过分析图像直通波位置的变化,可以定量给出纵波声速的数值。从计算出得数值中我们可以看出充氢80小时后纵波降低的程度最为明显,充氢18小时波速变化幅度很小。 /(7/)充氢时间越长,试样的腐蚀越严重,超声波衰减也越严重。 /(8/)20号钢和Q345R材料在450℃、18MPa氢分压的环境中进行充氢腐蚀,性能劣化的临界时间在18小时附近。 At the condition of high temperature and high pressure, some equipments in the chemical industry, petroleum refining industry, petroleum chemical industry, coal industry are attacked by the hydrogen. High temperature hydrogen attack /(HTHA/) is one of the typical damage, it has great harmfulness, has great influence on safe operation of equipments and has great threatening on people's lives and property. Combining with research achievements in the HTHA experiment before Specimens made of20steel and Q345R steel are exposed to hydrogen gas at450℃with a hydrogen partial pressure18MPa for18hours, the degree of corrosion is characterized and evaluate by velocity ratio、thickness measurement, TOFD, macroscopic and microscopic examination and hardness test. Comparing with data from the samples corroded36hours and80hours, we have summarized the relationship between corrosion degree and the time of filling hydrogen and examined the HTHA by the ultrasonic method. Research results show that: /(1/) After have corroded for18hours36hours80hours, the sample experienced the process from no changing on the surface to having a dense bubbling, then to appearing cracks. /(2/) Along with corrosion time increases, surface decarburization and completely decarburization near surface and grain boundary microcrack appears in order on the samples. /(3/) The longer corrosion time is, the greater material properties falls, the more hardness value drops. /(4/) The thickness of sample increases after corrosion, and the corrosion degree increase continuously by time. /(5/)The velocity ratio increases by the time after the corrosion of18hours, velocity ratio change a little,the HTHA stays at early stage.Velocity ratio exceed0.55after corrosion of36hours The material has been hydrogen corrosion. the velocity ratio is about0.57and the sample corroded more. /(6/) The direct wave of TOFD occurred the time delay after corrosion, velocity wave becomes slower. Through the changes of direct wave position, we can obtain the data of longitudinal velocity. from the data,we can see that the velocity reduce most after corrosion of80hours,and the velocity reduce least after corrosion of16hours. /(7/) The longer corrosion time is, the worse corrosion of sample is, the harder attenuation is. /(8/) Specimens made of20steel and Q345R steel are exposed to hydrogen gas at450℃with a hydrogen partial pressure18MPa, and the critical time of performance degradation is18hours nearby.

关 键 词： 压力容器 高温氢腐蚀 超声波检测

分 类 号： [TG174.3]

领　　域： [金属学及工艺] [金属学及工艺]