| Vertical continuous annealing is an advanced production technology in producinghigh-grade strips, which has the incomparable advantage than other annealing processes.Fast cooling technique is the core technology of continuous annealing. Even verticalannealing furnace section of high-speed impact of the fast cooling jet will cause theviolent vibration of strip. The vibration will cause many quality problems of strip suchas uneven or even breakage. Strip hot-dip galvanizing line is also face the sameproblem.At present, the contact-type of installation stabilizing roll is widely used toeliminate vibration. While electromagnetic suppression technique is used by someenterprises abroad and Bao Steel. But both these two techniques are all imperfection.Referring to the actual working characteristics that strip in the fast cooling part of avertical annealing furnace section, and combining the existing literature, we will studyhow to establish the experimental facility of simulation of strip vibration underlaboratory conditions and its research methods. Under the environment of ANSYSsoftware, modal analysis was carried out on the draping strip with taking advantage offinite element analysis. The inhomogeneity of the surface force which the impact jetflow brings to strip, the difference of both sides, the volatility of airflow and thedisorder of the impact jet flow cause the vibration of the strip, whose distortion andmovement act on strip in return. This brings about complex multiple repeatedinteraction coupling. The increasing of strip’s torsional pendulum amplitude and thejammed of touchable nozzle are mainly caused by self-motivation cycling expansileeffect which produced in strip vibration process.Experiment examines the influence of strip vibration with different nozzle’s formsof the spray box. It also probe into the combination box’s jet stream velocity, striptension, strip steel running deviation, velocity difference of both left and right spray box,and strip thickness and their influences on strip’s vibration amplitude, peak value andspectral distribution.The experiment will explore3technique proposals of the inhibition of the stripvibration without external suppression measures such as stabilizing roll. Through theweakened incentive and the inhibition of formation of self-motivation cycling expansileeffect, strip vibration is effectively suppressed. The consistency effect is also achieved in the test rigs when these3technique proposals are separately studied in spraybox1:2.5scale test rig, spray box1:5test rig and combination box1:5scale test rig.Among them, Solution1has the best inhibitory effect.Through the experimental study, we learn that vibration performance andmechanism of strip and also find out the effective technology to inhibit strip vibration.These all provided effective reference for the study and the reasonable adjustment in theprocess of strip vibration. |
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