Study on Recycle of Water-soluble Coolant

To decrease the environmental load and waste cost of water-soluble cutting fluids, we have focused on the water recycling system for waste water-soluble cutting fluids. In earlier studies, we found that some waste-water soluble cutting fluids can be processed in the recycling system. Especially, an amine-free cutting fluid showed good recyclability in lower costs and has better or equal cooling and lubricating performance compared with other types of coolants. However, the amine-free water-soluble cutting fluid showed poor corrosion inhibition performance in general machining operation. Moreover, the surfactant used in recycling process worsening the corrosion inhibition performance of the recycled water-soluble cutting fluid. In this study, we employed three types of surfactant for a corrosion inhibition performance improved amine-free cutting fluid, and examined the changes of corrosion inhibition performance of the recycled coolant.