The Fault Diagnosis Of Sendzimir Mill

Sendzimir mill(the brief name is ZR mill)is one of the key equipments in silicon steel strip production.The fault frequency of twine roller fault and gear box fault is very high in production.The faults result in stop production for long hours to substitute for the roller and overhaul each time,whose economic lose is vast..It has extremely vital significance in enhancing the ZR mill productivity and guaranteeing the safety in production and improving the product quality to find out the main reason resulting in the roller trouble by monitoring, put forward measures that avoids or lighten the degree in rolling-damage as well as apply the morden fault character extraction methods such as the wavelet transform to analysis the vibration signal of the gear box and judges whether it has the breakdown.This article take some Sendzimir mill ZR22BS-42 the ZR mill as the research object, carry on some research on its urgent open system and the master drive system. Main content described in this article is as follows:1. Monitor and the diagnosis of twine roller faultThe scene investigation discovered that when the ZR1 rolling mill occurs twine roller fault accident, the roller department's extent of damage is lighter than that of the ZR3 mill roller.Therefore to recorde through on-line monitor equipment the ZR1 mill and in the ZR3 mill urgent open system each hydraulic pressure part lag in response time, presses about the cylinder the cavity differential pressure, parameters and the roller host electrical machinery rotational speed and so on when the steel belt break down.The result is as follows: (l)Two rolling mills urgent open system lag in response time are same;(2) The move speed of cylinder piston is 2.5 times than 66mm/S when ZR3 rolls push down cylinder piston;and when ZR1 rolls press cylinder piston the move speed is 30mm/S. (3) The stopped time is approximately 8 seconds when ZR1 rolling mill stop from the highest rolling down speed -450m/min to zero. The stopped time will be long if the roll mill is at low speed;the stopped time is also 8 seconds when ZR3 rolling mill stop from the highest rolling down speed -600m/min to zero. (4) The ZR1 rolling mill examine the fault of crack through overtravel-limit switch.The ZR3 rolling mill examine the fault of crack through the tensiometer change rate examination.Through the test we discovered the examination lag time of the ZR1 rolling mill rolls is 0.2 second longer than that of the ZR3 rolling mill.In view of the above test,we can draw conclusions as follows:(1) From the view of draught pressure change after the fault of crack and various rollers relative friction,the roller department's open speed have to be reasonable.(2) The ZR1 roll mill and ZR3 roll mill reduce the stopped time.(3) Improve the examination way of the ZR1 rolling mill.2.The wavelet analysis method applying in the typical fault characteristic extractionThe ZR rolling mill gear box's structure is complex. It is inevitable that the gathering vibration signal includes massive noise signal.It is extremely important to accurately extraction the fault information from the low Signal-to-Noise(SNR) signals for enhancing the gear boxdiagnosis accuracy, The author has done some research and consummations about the extraction method of impulse signal which is based on the Morlet wavelet transformation and the biggest likelihood estimating method and the wavelet -AR spectrum estimating method. The extraction method of impulse signal based on the Morlet wavelet transformation and the biggest likelihood estimating method is based on the similarity of the Morlet wavelet and impulse signal, This method concentrates the energy of impulse signal in a small part of wavelet coefficient,then uses noise signal probability density function normal distribute characteristic and the characteristic of the impact signal probability density function has the peak value in the zero spot, carries on biggest likelihood threshold value processing with the coefficient through the Morlet wavelet transformation,finally carries on the heavyconstruction with the contracted wavelet coefficient.So we can reduct noise. It is very important whether the impact signal and noise signal standard difference estimate is right,because it will be vital to obtain the appropriate threshold value and gain good effect of noise reduction. The author carries on the different criterion with the wavelet to the signal decomposition Then high frequency and the low-frequency signal will be constructed again respectively.Then estimate the standard difference of high-frequency heavy construction signal and the low-frequency heavy construction signal. We can obtain the impact signal standard difference and the noise signal standard difference accurately. The wavelet -AR spectrum estimating method firstly uses the tools which includes binary orthogonal wavelet the decomposition and the heavy construction function in Matlab wavelet toolbox, and reduce the frequency band of vibrate signal to the vicinity of fault characteristic frequency.We use the AR spectrum estimating's merit of energy centralism to carry spectrum estimate on the processed signal and find out the characteristic frequency. Two methods mentioned above have the same merit which can extract the fault information accurately from he vibration signal that includes massive disturbances noise . 3 Sendzimir mill gear box breakdown monitor and the diagnosisGear box are important constituent of the ZR mill master drive system. It is self-evident that monitor and diagnose is significant. Their structure is complicated. When we carrier on the vibration test, there is massive noise jamming signal mixed in the vibration acceleration signal. The author firstly carries on simple diagnosis using the characteristic value in the ZR rolling mill gear distributor case. Then using FFT, the enveloping spectrum and its thin technology carries on the precise diagnosis in its bearing. Then using the extraction method of impulse signal which is based on the Morlet wavelet transformation and the biggest likelihood estimating method and the wavelet -AR spectrum estimating method to diagnose its gear. The result indicated that The ZR3 gear distributor case gears vice- revolution is normal; Gear vice- cl -c51, c4 -c3 exist hidden danger because of attrition in early time; The zl bearing (24,148), the z2 bearing (23,144), the zl2 bearing(23,236) has the slight pitting.