Vibration Characteristics Research During Service Life Of Sink Roll In Cold-Rolling Strip Steel Hot-dip Galvanizing Line

Steel strip hot dip galvanizing technology is one of the important measures for corrosionprotection of steel, which is widely-used in industry, agriculture and construction industry. Thefrequent vibration of the zinc pot sink roll components (sink roll, shaft sleeve and gap block) inthe hot-galvanized line of cold-rolled strip steel seriously affected the surface quality andproduction efficiency, so it is very necessary to research the vibration of sink roll in the liquidzinc. According to the work environment of sink roll, the model of fluid-structure interactionfinite element is established and the natural frequencies and mode shapes are calculated. Thefield test shows that the vibration of the sink roll is closely related to its structure. Furthermore,the finite element dynamic models of the sink roll components and strip steel are established.According to the calculation results, improvement measures are proposed.The main work and conclusions of this dissertation are as follows:1) The vibration of sink roll in the working time was introduced. And then the vibrationcharacteristics of sink roll were studied combine with the theory of mechanical vibration andfault diagnosis;2) The finite element analysis model of fluid-structure interaction consist by liquid zinc andsink roll was established. The vibration mode of sink roll in liquid zinc was acquired. Combinedwith the field test, the vibration characteristics of sink roll in fluid-structure interaction was fullyunderstood;3) Forces of sink roll and shaft sleeve were separately analyzed. Deflection bending valueof sink roll under the strip tension was calculated using material mechanics deflection formulaand finite element method; the contact stress between shaft sleeve and gap block was calculatedrespectively by Hertz formula and finite element method, and find out the direct influencingfactor of shaft sleeve with irregular wear. Structural improvement has been proposed by finiteelement calculation and field test.Through the analysis of theory and experiment, the measures of increasing the length ofcontact line and the diameter of the collar and bush were proposed to extend the service life ofsink roll components.