In-situ interfacial tribochemistry toward eliminating red-scale of silicon steel in friction process

Irregularly striped red-scale defects are often formed on hot rolled silicon steel strips, and some still remain on the surface even after pickling. In this study, an in-situ interfacial tribochemistry concept was proposed to eliminate red-scale silicon steel using ball-on-disc test, by transforming harder eutectic Fe2SiO4/FeO eutectic into other compounds with sodium polyphosphate lubricant. The results show that polyphosphate can lubricate the high speed steel/silicon steel interface effectively with significant reduction of the friction and wear by 50% and 90% respectively. And in situ formed compounds of Na3Fe2(PO4)(3) and NaFePO4 at the rubbing interface can eliminate red-scale on silicon steel by weakening the adhesion of oxide scale to the substrate.