热镀锌机组沉没辊系刮刀力预报及影响因素

 针对热镀锌机组沉没辊系表面锌渣刮不干净而导致带钢表面出现较多辊印缺陷、严重影响板带产品质量等级的问题,充分结合热镀锌机组设备与其工艺特点,首先对沉没辊系刮刀机构进行受力分析,在此基础上建立稳态条件下刮刀力模型。考虑沉没辊系在实际工况中存在的轴套与轴瓦间隙波动、沉积于辊面的残留锌渣、刮刀磨损等因素对刮刀力的影响,对刮刀力模型进行了修正,使其对非稳态条件下刮刀力计算同样适用。然后,分析了刮刀角度、轴颈偏心距、刮刀刃磨损量、辊面残留锌渣对刮刀力影响的机理,根据刮刀力修正模型制定了刮刀力计算流程,并将该模型应用于实际生产。选取3种典型规格带钢进行刮刀力预报,刮刀力预报值与实测值的相对误差小于15%,且满足机组所需的精度要求。最后,以规格A带钢为例分析带钢生产工艺参数(带钢张力、带速、表面镀锌量)对刮刀力预报值的影响。结果表明,刮刀力随着刮刀角度在小范围内(9°~12°)增大而增大;刮刀力随着轴颈偏心距的增大呈较快速非线性增大;刮刀刀刃磨损增加会降低刮刀去渣能力;辊面残留锌渣量的增加导致刮刀力增大,容易造成辊系卡死或打滑现象发生。刮刀力与带钢张力呈近似线性递增关系,而与带速呈近似线性递减关系,但表面镀锌量对刮刀力影响相对较小。

Prediction and influencing factors of scraper force for sink roll system of hot dip galvanizing unit

The sink roll in hot galvanizing units blown not clean on the surface of zinc slag leads to the strip surface defects, which seriously affect strip product quality grades. The characteristics of equipment and process of hot galvanizing unit were combined in this paper. Firstly, the force of sink rollers scraper mechanism was analyzed and the model of scraper force was established on the basis of steady state condition. Considering the influence of gap fluctuation between axle sleeve and bearing bush, the residual zinc residue deposited on the roll surface and the blade wear on the blade force in the actual working conditions of sink roll system, the scraper force model was modified to calculate the scraper force under unsteady conditions. Then the influence mechanism of scraper angle, journal eccentricity, blade wear and residual zinc residue on scraper force was analyzed. The calculation process of scraper force was developed according to the scraper force modification model, and the model was applied to actual production. Three typical specifications of strip steel were selected to predict the scraper force. The relative error between the predicted value and the measured value was less than 15%, and met the precision requirement of the unit. Finally, the influence of strip production parameters (strip tension, strip speed, surface galvanization) on the predicted value of scraper force was analyzed by taking strip A as an example. The results show that the scraper force increases with the increase of scraper angle in a small range (9°-12°), and the scraper force increases nonlinearly with the journal eccentricity increasing. The increase of blade wear will reduce the slag removal ability of scraper. The increase of residual zinc residue on the roller surface leads to the increase of scraper force, which is easy to cause the phenomenon of roller system sticking or slipping. The scraper force increases linearly with strip tension and decreases linearly with strip speed, but the influence of surface galvanization on scraper force is relatively small.