1, when rinsing pollution
Fastener hardened silicate cleanser, then rinse, XX appears on the surface of solid material, will analyze this with infrared spectrometer, proved to be inorganic silicates and iron oxides. Fasteners 2, piling up unreasonable
Fasteners tempered after signs of discoloration, cover with ether, ether found oily residue left after the volatile, such material is the high content of fat.
3, surface residue
High strength bolts with white residue, analyzed by infrared spectrometer, proved to be the phosphide. No acid cleanser and rinse tank inspection found tank has a higher solubility of carbon, should carry out periodic tank drained, often detect lye concentration in the washing tank.
4, alkali burn
Waste heat from high-strength screw hardened Black Black outer surface with uniform and smooth. But the outer ring with orange XX visible to the naked eye.
5, improper rinsing
Fasteners are often used for large size is quenched polymer in aqueous, alkaline cleaning agent for cleaning and rinsing before quenching, quenching of fasteners in rust on the inside.
6, excessive corrosion
Rust in the calcium and sulfur shows that the latter is baked dry quenching oil, is also gas-phase quenching process of evolution. Because excessive aging of quenching oils recommended pour old oil, add new oil, all the technology cycle, implementation of process monitoring and maintenance of quenching oils.