This article specifically discusses the complexity of industrial gear oil.

Compared with vehicle gear oil, industrial gear oil is more complex because its equipment operates in diverse environments, such as easy contact with water, humid environments, dust pollution, etc. It involves many industries, such as steel, mining, construction, non-ferrous metals, etc., with a wide range of viscosity types and large spans, ranging from 68 # to 1000 # or even higher. The gear materials are special, such as worm gears. In this way, a series of problems have arisen for industrial gear oil, such as how to improve its oxidation stability and thermal stability to ensure a long oil change period, how to ensure its anti emulsification performance and anti foam performance after the oil is polluted. With the improvement of equipment manufacturing precision, more and more testing equipment has been introduced by OEMs to evaluate the quality of industrial gear oil, bearing wear, bearing corrosion, etc. Even some special users have put forward higher requirements for the cleanliness of oil products.

In addition to the basic difference between closed gears and open gears, more complex situations can be understood by just one example: we classify worm gear oil into industrial gear oil. Worm gear is actually an extreme form of hyperbolic gear, and the gear shaft can achieve large offset. The material of worm gear is usually steel with high hardness, while the turbine is bronze (an alloy of copper, tin or lead). In theory, the gear teeth are in point contact under pure sliding conditions, with high relative sliding speed and high temperature on the tooth surface. The oil film is easily damaged, and the lubrication conditions are harsh. The friction characteristics of steel copper and steel steel friction pairs are definitely different, so there are differences in the emphasis of the formula, which makes the selection of additives more complicated.

Speaking of open gear oil, it is suitable for devices that include open gears, semi closed gears, and certain low-speed gear devices. It is divided into ordinary and extreme pressure types, and must have good adhesion. It is also the most important property of open gear oil, which is necessary to maintain an oil film on the tooth surface and prevent oil droplets from splashing and dripping. Therefore, adhesive agents need to be added. More complexly, it is also divided into diluted and non diluted types. As a result, adhesive agents are prone to adhere to dust, causing abrasive wear. You can imagine the operating environment of open gear oil in an environment like a ball mill for ore or coal!

Furthermore, in the research and development process of industrial gear oil, some testing instruments and equipment for testing methods are also a confusing factor. For example, the TIMKEN testing machine, which has already entered the standard, is very sensitive to the structure of load additives (extreme pressure anti-wear agents) in terms of OK load. Experienced test operators know that the material, hardness, and direction of processing marks of the test ring block will all affect the results of OK load. Moreover, studies have shown that the reproducibility of OK load is very average, with a reproducibility of ± 10 pounds for base oil; Medium extreme pressure oil, ± 15 pounds; High extreme pressure oil, ± 20 pounds. Therefore, the TIMKEN test is used to distinguish between base oil and extreme pressure oil, and has a certain degree of reliability, but we have to have doubts about its use to evaluate the extreme pressure level of oil.

As mentioned above, the cleanliness of industrial gear oil will undoubtedly become a new concern of users in the future, and the foam performance is a difficult use performance of industrial gear oil. Adding too much antifoam agent will not only affect the efficiency of extreme pressure antiwear agent, but also have a negative impact on the cleanliness.

All of the above are topics that we cannot avoid in the future.