Does the effectiveness of metalworking fluid corrosion inhibitors decrease over time or with increased processing volume?

The effectiveness of metalworking fluid preservatives does decrease over time or as the amount of processing increases. Preservatives work by reacting with metal surfaces to form a protective film that prevents corrosion. However, this effect is not permanent, and the concentration and activity of the preservatives will gradually decrease over time, affecting their anti-corrosion effect.
Preservatives in metalworking fluids are affected by temperature, humidity, and the processing environment. High temperatures, shear forces, and contact with metal surfaces during processing can accelerate the decomposition or volatilization of preservatives. For example, under high temperatures and high shear forces, preservatives may lose some of their active ingredients due to evaporation or chemical reactions, resulting in a decrease in their anti-corrosion performance. In addition, as the processing fluid continues to contact the metal surface, the active ingredients of the preservatives will also be consumed, and the remaining preservative concentration will gradually decrease.
As the amount of processing increases, impurities, metal ions, grease, etc. in metalworking fluids will gradually accumulate, and these impurities will affect the effect of preservatives. For example, iron ions, copper ions, etc. in metalworking fluids will react with preservatives, reducing their anti-corrosion effect. At the same time, substances such as grease and cuttings may form a film or deposit that covers the metal surface, reducing the contact area of ​​the preservative and thus affecting its anti-corrosion effect.
Contamination of metalworking fluids can also accelerate the decline of the effectiveness of preservatives. During long-term use, the fluid may absorb moisture or other harmful substances in the air, which will change the chemical properties of the preservative and further reduce its anti-corrosion performance. As the concentration of preservatives in the processing fluid decreases, the protective film on the metal surface gradually becomes thinner, and the metal surface is more susceptible to corrosion.
In order to maintain the effectiveness of the preservative, regular testing and replenishment of preservatives are very necessary. Some advanced metalworking fluid formulas may contain self-recovery ingredients that can replenish or activate preservatives to a certain extent, but these functions are usually limited and cannot completely replace the need for regular replacement and addition of preservatives. Therefore, when using metalworking fluids, users need to regularly check the state of the fluid and the effectiveness of the preservative according to actual usage to ensure that it is in the best working condition for a long time.