Some people refer to spray soaking cleaning as chemical degreasing, which means that the oil on the surface of the steel strip is removed by the saponification, emulsification, and decomposition effects of the degreasing agent.

(1)皂化作用。如果冷轧工序使用的轧制油主要是采用动物油和植物油配制而成的，这种类型的油通称为皂化油。在脱脂过程中碱组分能与这些不溶于水的油类发生反应，生成能溶于水的肥皂，从而去除。

(1) Saponification. If the rolling oil used in the cold rolling process is mainly composed of animal oil and vegetable oil, this type of oil is commonly referred to as saponified oil. During the degreasing process, the alkaline components can react with these insoluble oils to form soap that is soluble in water and thus removed.

(2)乳化作用。如果轧制油中存在矿物油。它属于非皂化油，基本上不能与碱发生皂化反应，则须靠表面活性剂的乳化作用来去除。乳化作用过程可。

(2) Emulsification effect. If mineral oil is present in the rolling oil. It belongs to non saponified oil, and can not saponification with alkali basically, so it must be removed by emulsification of surfactant. The emulsification process is feasible.

表面活性剂能降低水表面的张力，这样能使本来平铺在钢带表面的油膜卷离成小油珠，从而乳化。而且表面活性剂还能在乳化了的油珠表面形成厚度的界面膜，使乳化液比较稳定，油污质点悬浮于清洗液之中，不再沉积到钢带表面。

Surfactants can reduce the tension of the water surface, which can cause the oil film that was originally laid on the surface of the steel strip to roll off into small oil droplets, thereby emulsifying. Moreover, the surfactant can also form a thick interfacial facial mask on the emulsified oil bead surface, which makes the emulsion relatively stable, and the oil particles are suspended in the cleaning solution and no longer deposit on the surface of the steel strip.

(3)分散作用。对于钢带表面不溶于水的固体污垢的去除，靠表面活性剂的分散作用。离子型的表面活性剂能在固体颗粒表面被吸附，使所有的粒子都带有相同的电荷，从而相互排斥而分散开来。此时表面活性剂的亲油基定向排列于固体颗粒表面，亲水基朝向水中。这样也可使清洗液与固体粒子的界面张力小于粒子之间的内聚力，防止粒子再聚结在一起。

(3) Dispersion effect. The removal of solid dirt on the surface of steel strips that is insoluble in water relies on the dispersing effect of surfactants. Ionic surfactants can be adsorbed on the surface of solid particles, causing all particles to have the same charge, thereby repelling each other and dispersing. At this point, the hydrophilic group of the surfactant is oriented on the surface of the solid particles, and the hydrophilic group is oriented towards the water. This can also reduce the interfacial tension between the cleaning solution and solid particles to less than the cohesive force between the particles, preventing them from coalescing again.