【正文】 fault diagnosing1　PrefaceRolling machine is a large rotating machinery, is the key to rolling mill equipment. Shaft ponent is the core part of the mill, which includes the axis of rotation, gear parts, couplings, sliding and rolling bearings and so on. People through observation and practice, found that the vast majority of rotating machinery fault will show the preabnormal vibration, therefore the general law of mechanical vibration control can be identified from the vibration signals of mon equipment failure. Vibration waveform by a simple time domain, frequency domain and wavelet analysis can be a general recognition on the vibration, the vibration can be identified is a mechanical fault of noise and vibration test and analysis of technical premise. Therefore, the use of diagnostic technology in equipment vibration analysis of more mature technology, a breakthrough technology as a routine of rolling mill vibration condition monitoring, equipment operation will be able to remove all equipment or basically not the case, control mill running, determine the production the location and cause of failure, and predict the future state of technology, which can be effective in the early discovery and inhibit the breakdown in the later time to ensure the production of sustainable development.2　Signal recognition and access toEquipment in the operation of any machine will have a vibration, the machine vibration signal contains a wealth of machine operating status information. Exception occurs when the device or failure, the vibration will change, usually expressed as amplitude increased. By different types, nature, causes and location of the fault produced by the vibration excited with different characteristics, such characteristics as frequency ponents, amplitude of the phase difference between waveform shape and energy distribution and so on. The nature and characteristics of vibration signals trouble not only, but also the inherent characteristics of the system related to the specific performance of different parts of the same fault, fault excitation transfer channel (ie transfer function) is different, the vibration characteristics and the response will also have greater difference. In short, the device is the vibration characteristics of the fault system of incentives and joint decision, but in many cases, vibration characteristics and failure is not a one to one relationship between types, not simply the condemnation, which brought recognition to the vibration certain difficulties. Therefore, identification of vibration diagnosis technology for improved equipment is essential. Rolling mill machinery at work be noncontinuous rolling rolling, and its speed is not constant, the power is from no load to full load to fluctuate between periods. Roll from the original motivation to drive between large and slow institutions, many types of problems that may occur, so testing equipment, measuring point, pointlocation and time of Inspection on the diagnostic accuracy of the choice of whether or not play a key role. To ensure parability of the measured data, in the determination of the principles of data should follow the following points: ① each measurement point in the same measure, or the excitation source to the transfer function of the different measuring points, leaving the difference between the measurement results great. ② each measurement to keep the machine the same conditions. ③ to maintain the same parameters measured, in general, the frequency of vibration in the 10 ~ 100Hz data acquisition should be based on displacement as the output parameter, the frequency in 100 ~ 1 000Hz vibration data acquisition should speed as the output parameters, frequency above 1000Hz vibration acceleration should be taken as the number of output parameters. ④ using the same instruments and measurement methods (such as sensor and a fixed way) the same. In the vibration process, the choice of measurement points also affect the monitoring results, the choice of principles:朗讀顯示對(duì)應(yīng)的拉丁字符的拼音字典(1) The measuring point should be selected in the vibration signal transmission channel and the location of the shortest route to minimize the intermediate transfer media.(2) The measuring point should be selected in the most sensitive parts of the signal, such as housing, frame and so on.(3) The measuring point should be chosen in place to facilitate multidirectional measurements. General measure vibration in three directions to be selected (the level of X, the vertical Y, axis A) to evaluate, especially for low frequency vibration, but also to emphasize the direction (highfrequency vibration on the direction is not sensitive).(4) for large mechanical equipment, by the transfer function should be more testing.3　steel rolling machinery, and other mon faults and rotating machineryThe diagnosisCommon rotating machinery faults, according to the nature of the rotor and vibration type can be divided into: rotor unbalance, rotor misalignment, loose base or assembly, the rotor and stator friction, induction motor vibration, bearing failure, vibration and other gear mechanism . Vibration monitoring technique using these mon mechanical failure can be a more accurate diagnosis.3. 1　 Rotor imbalanceRotating Machinery imbalance is the most mon form of failure. Imbalance caused by many reasons, such as the eccentricity caused by poor installation, with the loosening, axial bending, manufacturing errors, and generate longterm operation uneven wear. Our formula from the centrifugal force is easy to know, unbalance vibration of engine speed is the most sensitive. The vibration characteristics of rotor imbalance is: rigid rotor speed at startup, the amplitude increases, the amplitude of flexible rotor at startup is to increase and then decrease. In the frequency characteristics, the unbalance vibration of the frequency ponents of a single, clear, mainly the fundamental frequency of the rotor。利用