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。如果冷軋工序使用的軋制油主要是采用動物油和植物油配制而成的，這種類型的油通稱為皂化油。在脫脂過程中堿組分能與這些不溶于水的油類發生反應，生成能溶于水的肥皂，從而去除。

(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。如果軋制油中存在礦物油。它屬于非皂化油，基本上不能與堿發生皂化反應，則須靠表面活性劑的乳化作用來去除。乳化作用過程可。

(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.

表面活性劑能降低水表面的張力，這樣就能使本來平鋪在鋼帶表面的油膜卷離成小油珠，從而乳化。而且表面活性劑還能在乳化了的油珠表面形成厚度的界面膜，使乳化液比較穩定，油污質點懸浮于清洗液之中，不再沉積到鋼帶表面。

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。對于鋼帶表面不溶于水的固體污垢的去除，就靠表面活性劑的分散作用。離子型的表面活性劑能在固體顆粒表面被吸附，使所有的粒子都帶有相同的電荷，從而相互排斥而分散開來。此時表面活性劑的親油基定向排列于固體顆粒表面，親水基朝向水中。這樣也可使清洗液與固體粒子的界面張力小于粒子之間的內聚力，防止粒子再聚結在一起。

(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.