Research On The Identifi Cation And Classifi Cation Method Of Bearin G Steel Based On Low Frequency Eddy Current Detection

Raw material testing is essential to ensure the reliability of bearing ring production,the actual industrial production process is mainly through spark identification,spectral analysis and other means to achieve the identification and sorting of bearing steel.However,these techniques are time-consuming and difficult to implement,and usually require sampling and testing of raw materials in the laboratory,which cannot fundamentally solve the problem of misuse of raw materials in the production process of bearing rings.In recent years eddy current inspection has been widely used in the field of metal material sorting and metal flaw detection,which has the advantages of strong antiinterference,fast detection speed,low cost and non-contact.Therefore,this paper designs a low-frequency eddy current inspection system for the identification and classification of raw materials of bearing steel,which lays the foundation for the online inspection of raw materials in the bearing production process.The specific work of the article is as follows:(1)The basic principle of bearing steel eddy current detection is explained,and the eddy current probes are classified according to the different induction,placement and signal acquisition methods,and the best induction method for bearing steel sorting in this paper is mutual induction,the best placement method is external penetration,and the best signal acquisition method is heby differential.The finite element simulation of the magnetic field was carried out using COMSOL software to investigate the effects of excitation frequency,excitation amplitude,conductivity and relative permeability on the eddy current distribution and induced voltage inside the bearing steel.(2)A low-frequency eddy current detection system for bearing steel classification was designed to obtain the amplitude and phase difference information of the eddy current induced voltage,an ACCESS database was established to store and query the data,and the experimental feasibility of each module of the low-frequency eddy current detection system was verified through experiments.The effect of excitation signal amplitude and frequency on the induced voltage was investigated,and the optimal excitation signal amplitude and frequency for the low-frequency eddy current detection system were obtained as 27 V and 120 Hz,respectively.At the same time,an experimental study was conducted using three types of bearing steel: enterprise field steel,rusted steel and steel with scratches,and it was found that the eddy current inspection system in this paper is not affected by rust and shallow scratches that cause misclassification.(3)Bearing steel classification experiments were conducted with the help of the eddy current inspection system designed in this paper,and it was found that the system can identify different grades of bearing steel,such as SUJ2 R,SXJN1,GCr15 and 100Cr6;it can identify annealed and unannealed bearing steel;it can identify bearing steel with different furnace outputs;and it can identify bearing steel with different diameter sizes.