摘要
采用沸腾硝酸法和声发射技术研究了敏化316L奥氏体不锈钢的晶间腐蚀特性.通过失重法对3个周期实验的腐蚀速率进行计算和评定,并利用金相显微镜观察了各周期实验后试样腐蚀形貌;同时利用声发射检测系统实时采集了实验过程中的晶间腐蚀声发射信号,通过对信号进行参数分析和小波分析探究了敏化316L不锈钢晶间腐蚀的声发射信号特征与规律.实验结果表明,敏化316L不锈钢的晶间腐蚀分为腐蚀萌生阶段、平稳腐蚀阶段和快速腐蚀阶段;对信号进行参数分析发现各腐蚀阶段的计数率先缓慢增大继而保持平稳不变,最后又迅速增大;信号幅值出现明显的分层现象：腐蚀萌生阶段为25～27dB,平稳腐蚀阶段为27～30dB,快速腐蚀阶段为31～34 dB;最后对信号进行小波分析发现声发射信号主要由频率为200、280kHz的信号组成.
Making use of boiling nitric acid method and AE technology, the inter-granular corrosion of sensi- tized 316L austenitic stainless steel was studied; and having weight-loss method used to calculate corrosion rate in three-cycle experiments and the metallographic microscope employed to observe samples＇ corrosion mor- phology;and having acoustic emission signals of inter-granular corrosion in experiments collected and their pa- rameters analyzed with wavelet analysis method can explore both characteristics and laws of the sensitized 316L stainless steel＇s acoustic emission signals in the inter-granular corrosion. The experimental results show that the corrosion initiation stage, steady corrosion stage and rapid corrosion stage constitute the inter-granular cor- rosion of the sensitized 316L stainless steel; the parametric analysis shows that the count ratio of every corro- sion stage can rise slowly at first, then become smooth and steady and finally increase rapidly; and the signal amplitude has significantly-layered phenomenon, i.e. 25dB to 27dB for the corrosion initiation stage, and 27 dB to 30 dB for the steady corrosion stage as well as 31 dB to 34 dB for the rapid corrosion stage; the wavelet analysis shows that signals with frequency of 200kHz to 280kHz mainly make up the acoustic emission signal.
出处
《化工机械》
CAS
2013年第6期728-732,共5页
Chemical Engineering & Machinery
基金
国家科技重大专项课题资助项目(2011ZX06004-009)
关键词
316L不锈钢
晶间腐蚀
声发射
参数分析
小波分析
316L stainless steel, inter-granular corrosion, acoustic emission, parameter analysis, wavelet analysis
