Quenching medium

　　The cooling medium used in the quenching process is called quenching medium. Pinghuo medium plays an important role in ensuring the implementation of foreign fire technology. The classification of quenching media is shown in the table.

Table 2-1 Classification of Quenching Media

　　The first type of liquid quenching medium

　　1. Water

　　2. Water solution: inorganic aqueous solution, organic aqueous solution, emulsion, and mixed solution of two or more substances

　　3. Quenching oil: ordinary Pinghuo oil, special quenching oil, mechanical oil, and two or more blended oils

　　4. Hot bath: molten salt bath, alkali bath, salt alkali mixed bath, metal bath, etc

　　second kind

　　Gas quenching medium includes air and inert gases such as nitrogen, argon, helium, etc

class iii

　　Solid quenching medium metal plate, metal mold (internally water-cooled), and fluidized bed medium composed of solid particles mixed with compressed air or water

　　In current heat treatment production, about 50% of the quenching medium is water and salt/alkali solution, about 40% is oil, about 5% is nitrate bath, about 3% is polymer solution, about 1% is high-pressure inert gas, and about 1% is corundum powder fluidized bed.