What are the types and characteristics of antiwear hydraulic oil?

1) High zinc type (foreign called "conventional zinc type"): zinc content in oil ≥ 0.07%. This type of oil is the main type of HM oil at home and abroad. For steel steel friction pairs, such as high and medium pressure vane pumps, the anti-wear performance is the best. The high zinc type can be divided into high zinc and neutral high zinc. The neutral high zinc has better extreme pressure and wear resistance, while the alkaline high zinc has good oxidation resistance and thermal stability due to its high pH value and high alkalinity.
2) Low zinc type (foreign known as "stable zinc type"): the content of zinc in oil is less than 0.07%, generally 0.03% - 0.04%. It has good adaptability to materials. It is not only suitable for medium and high pressure vane pumps, but also for plunger pumps with copper and copper alloy.
3) Zinc free type (foreign called "non zinc type"): the oil does not contain zinc and other metal salts. It is mainly suitable for plunger pump. In addition to its high cost and less antiwear than zinc containing type, it is not easy to corrode the hydraulic system with copper and silver parts, and its water separation, hydrolysis stability, filterability and thermal oxidation stability are better.