Gas-jet wiping of continuous galvanized coatings

为了在汽车应用中保护钢板免受腐蚀，通常通过连续镀锌过程应用薄锌涂层。涂层厚度（通常以g/m2的涂层重量来测量）通常使用平面狭缝喷射装置（通常称为气刀）来控制。利用该装置，在锌液涂层上施加高压气流，使涂层受到剪切力，多余的锌液在重力作用下返回镀锌槽。然而，单槽喷射气刀现在已经达到了它的极限，无法以与钢铁行业期望的盈利结果一致的生产率水平生产汽车行业所需的非常薄的涂层。此外，已经确定来自单槽射流几何形状的射流与自身相互作用，导致涂层厚度不均匀，有时会导致内部或客户拒绝。

In order to protect sheet steels from corrosion in automotive applications, a thin zinc coating is often applied via the continuous galvanizing process. The coating thickness (usually measured in terms of the coating weight in g/m2) is conventionally controlled using a planar slot-jet device commonly referred to as an air knife. Using this device, a high pressure gas stream is applied to the liquid zinc coating, resulting in a shear force being applied to the coating and the excess liquid zinc returning to the galvanizing bath under the action of gravity. However, the single slot-jet air knife has now reached its limit in terms of being able to produce the very thin coatings being demanded by the automotive industry at productivity levels consistent with the desired profitability outcomes of the steel industry. Furthermore, it has been established that the jet flow from the single slot jet geometry interacts with itself, resulting in the coating thickness not being uniform and which sometimes leads to internal or customer rejections.