However , many factors may affect eddy current testing and it is hard to classify them , and how to extract information which indicating carburized layer depth in signals is very important 但影响涡流检测的因素很多，检测结果不尽如人意，如何提取信号中的反映渗碳层深度的信息非常重要。
Abstract : the average diffusion coefficient of carbon in surface layer of steel 20 rare ea rth carburized at 880 and 900 for 8 h was calculated by substituting the mea sured layer depths into the diffusion equation 文摘:通过对20钢常规气体渗碳和稀土渗碳层深的测定，计算出稀土渗碳时碳在奥氏体中的平均扩散系数。
Finite element preprocessor , eddy current electromagnetic field calculation , the postprocessor and the visualization processor were integrated together in the software system , and good graphic user interface was also offered 该系统将有限元前处理、涡流电磁场计算、渗碳层深度逆问题求解及计算结果的可视化处理结合起来，提供了良好的用户界面。
Abstract : a new simulating method is established for the calcul ation of the hardness profile of high - carbon - concentration deep - carburization , on the basis of analyzing this process and taking into account the influence o f carbide solution and dissolution , carbon - concentration and temperature on the diffusion behavior , and the influence of the environment factor on carbon trans fer through the gas - solid interface 文摘:在对高浓度深层渗碳的特点进行分析的基础上,考虑到碳化物的析出与溶解、温度及碳浓度对扩散行为的影响,气氛环境对相界面碳传递过程的影响,淬火烈度对渗碳层冷却效果的影响,提出了一种新的模拟高浓度深层渗碳渗层硬度分布的方法。
It is shown from results that increasing carburizing time further in the normal technology can not obviously deep the carburizing layer , but can cause nonmartensite microstructure at the bottom of the gear and coarse grain across the gear , these will heavily decrease the fatigue life of the gear 结果表明：在正常渗碳淬火工艺基础上再延长渗碳淬火1小时，齿轮渗碳层深度变化不大，但其齿根局部表面处有非马组织，且晶粒尺寸易产生异常长大现象，从而致使台架疲劳寿命明显下降。
This paper is introduced bp neutral network character , algorithm , designing principal on its construction and the designed product . input features extracted by the way described above into a bp neutral network , and using it to classify seven type of different carburized layer depth specimen . the result is indicated , using wavelet packet method to extract features and bp neutral network to classifying , is effective and precise to classify different metal carburized layer depth . it is useful and economical 本文介绍了bp神经网络的特点、算法和其结构的具体设计方法和设计结果，并将小波包提取的特征值输入到bp网络，对7种不同渗碳层深度的试件进行分类，实验结果表明，小波特征值提取和bp神经网络分类器相结合，可以实现对不同渗碳层深度的分类，效果良好，精度较高，有一定的实用价值。
Eddy current testing is a method suitable for testing changes occurred in the surface or subsurface of specimen . when using this method to test carburized components , the variable of eddy current signal is depend on the change of constituents " physical property in carburized layer . so it can be used to test carburized components nondestructively 涡流检测是一种适用于试件表面和近表面变化的检测方法，利用涡流方法检测渗碳件时，涡流检测信号的变化主要取决于渗碳层组织的物理特性的变化，所以涡流检测方法可以对金属表面渗碳层深度进行检测而不构成任何破坏。
