镀锌卷板表面锌灰成因及控制

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锌灰的出现是指镀锌钢板表面沿纵向形成条状或点状夹杂物，属于轻微缺陷，但其发生频率高于其它渣状缺陷。其原因是炉头锌层上的炉渣与炉头空腔中凝结的固体锌渣共同作用产生锌灰。

锌渣落在带钢表面，通过锌锅的沉辊与带钢产生轻微的压痕，或沿锌板表面纵向产生条状或点状夹杂物，造成锌灰缺陷的控制措施如下：1。优化后的炉头氮气加湿系统的加湿系统可以提高露点温度，使锌蒸气在锌液表面形成保护膜，抑制锌液的连续蒸发。当露点温度控制不当时，过多的水蒸气可能会造成缺陷。因此，实际生产中应确定合适的炉头露点温度。炉头锌渣清理1）制作专用清砂勺，每班清理炉头锌渣2-3次。2）在炉头增加锌渣吸附去除装置，通过风机将外部热风吹入密闭炉头3）利用停炉时间减少锌锅，露出炉头锌位，然后手动将炉渣镀锌卷3去除。钢带进锅温度控制1）严格控制钢带进锌锅温度，由于钢带温度超过锌液温度20度以上，不仅锌锅温度会升高，而且锌含量也会增加。2）严格控制锌锅温度，不超过（465+2）摄氏度，减少锌液温度波动，防止锌渣4的形成。锌溶液的成分控制与锌灰有很大关系。普通镀锌板控制范围为0.19-0.22%，合金镀锌板控制范围为0.10-0.15%。5个。锌锅变频调速过程中锌含量的降低，会使机头内渣粘附在机头内壁上。因此，应根据锌液消耗率合理确定加锌频率，防止锌液上下游水位波动和炉头内壁积渣。

The appearance of zinc ash refers to the formation of strip or point inclusions along the longitudinal direction on the surface of galvanized steel plate, which is a slight defect, but its occurrence frequency is higher than other slag defects. The reason is that the slag on the head zinc level and the solid zinc slag condensed in the head cavity act together to produce the zinc ash. The zinc slag falls on the surface of the strip steel, causes slight indentation with the strip steel through the sink roll of the zinc pot, or generates strip or spot inclusions along the longitudinal direction of the surface of the zinc plate, causing the zinc ash defect The control measures are as follows: 1. The optimized humidification system of nitrogen humidification system at the furnace head can increase the dew point temperature, make zinc vapor form a protective film on the surface of zinc liquid, and restrain the continuous evaporation of zinc liquid. When the dew point temperature is not controlled properly, excessive water vapor may cause defects. Therefore, the proper dew point temperature of furnace head should be determined in actual production 2. Cleaning of zinc slag at furnace head 1) make a special desilting spoon and clean the slag at furnace head 2-3 times per shift. 2) add the zinc slag adsorption and removal device at the furnace head, and blow the external hot air into the closed furnace head through the fan 3) use the shutdown time to reduce the zinc pot, expose the zinc position at the furnace head, and then manually remove the slag Galvanized coil 3. Temperature control of steel strip into the pot 1) strictly control the temperature of steel strip into the zinc pot, because the temperature of steel strip exceeds the temperature of zinc liquid by more than 20 degrees, not only the temperature of zinc pot will increase, but also the zinc content will increase. 2) strictly control the temperature of zinc pot, not exceeding (465 + 2) Celsius, reduce the temperature fluctuation of zinc liquid and prevent the formation of zinc slag 4. The composition control of zinc solution has a great relationship with zinc ash. The control range of common galvanized sheet is 0.19-0.22%, and that of alloy galvanized sheet is 0.10-0.15%. 5. The decrease of zinc level in the frequency control of zinc pot will make the internal slag of the nose adhere to the inner wall of the nose. Therefore, the zinc adding frequency should be determined reasonably according to the zinc liquid consumption rate to prevent the fluctuation of water level in the upstream and downstream of the zinc liquid and the accumulation of slag in the inner wall of the head.