Hi, welcome back to our website. Today in this article, we would like to talk about different methods to reduce friction. Where Lubricating Oil is Not Advisable as Lubricant also we will talk about different types of lubricants and their properties. So, these lubricants are used for various purposes in the industry and used for things like automobiles and all transportation; they all used these lubricants in gears & multiple kinds of machines. So, we will talk about the main classification and types of lubricants and what are their properties that are important for their application.
The types of liquid lubricants are divided into three main types –
The first is that natural oils, the second one is a mineral and then synthetic lubricants. One very important thing about lubricants is that the two most important properties of oils are viscosity and boundary lubrication. We will explain these two terms later on, but we should now understand viscosity and boundary lubrication. These two properties are extremely important for lubrication purposes.
Natural oils are the oils that we obtain from nature without much processing. In this, we have the animal fat vegetable oils. These are the two most important natural oils. These oils or fats have been used by human beings for lubrication purposes for Millennium before Mineral oil started being used. Mineral oils were invented in the mid-nineteenth century when we started getting petroleum from Oil well before that, throughout the history of human civilization, we have used animal fats or Vegetable oils for lubrication purposes.
These types of lubrication or oils are quite good for specific purposes; however, they have some problems like instability in an oxidative environment. They will be oxidized quite easily, especially in the thermal atmosphere. So if the temperature is high, they oxidize, and their property will degrade because of oxidation.
So, therefore these oils & fats cannot be used for most Machines because the machines tend to run at high loads and high speed, which means that the temperature will increase. So the second important also lubricating oils are mineral oil. the mineral comes from mines. That means something which we obtained from mines. These oils are derived from petroleum, and as you know, petroleum is obtained from Oil Wells. So these are like mines from underground. So that’s why the name comes from mines to mineral oils. That means all mineral oils are are derivatives of petroleum. Important mineral oils contain these molecules like paraffin, naphthenes, aromatic or mixed aromatic and aliphatic hydrocarbons.
So we can say that all mineral oils are hydrocarbons because petroleum gives us various molecular weight hydrocarbons. So during the fascination of petroleum, we obtain materials like fuels & lubricants of different molecular weights & different viscosity which have higher viscosity tend to have higher lubricating properties and their use as oils.
The problem with these mineral oils is that they contain Sulphur and oxygen, Phosphorus nitrogen etc.,
So these are considered as impurities & they have some issues in the application. Besides, they are contaminated for the environment. So, therefore, minerals oils must be purified as much as possible to reduce the impurities. Generally, they have a lower viscosity index. A high viscosity index means lubricating oils are more stable in high temp & a lower viscosity index means lubricants cannot stay steady in high temp & start losing lubricating properties when the temp begins to rise.
So, we have talked about mineral oils & now we are going to talk about synthetic oil.
So, what is synthetic oil?
As the name suggests, synthetic oils are produced by some chemical processes that are more stable at high temp with high viscosity index & able to withstand more load than mineral oils.
As the name suggests, synthetic oils are produced by some chemical processes that are more stable at high temp with high viscosity index & able to withstand more load than mineral oils. So, we can understand that synthetic oils have some good qualities that we can not find in mineral oil. Synthetic oil has hydrocarbons produced by polymerization, such as poly alpha-olefin, organic ester, polyglycerols and silicons. Silicons are not hydrocarbons. They are a mixer of silicons, oxygen & various other components. Synthetic oils have a high flash point & generally free of sludge & varnish deposits.
So, till now, we have discussed in detail lubricating oil. And in most cases, lubricating oil is the first preference for lubrication purposes of any application. But to lubricate any application, we need a closed system where we need to pour the oil & then oil will lubricate all the machine parts. But nowadays, in major industries, there are some applications where creating a closed system for the lubrication of machine parts is not possible. So, oil lubrication will not be likely possible. So, what can we do in this scenario?
So, in this scenario, greases come into the picture.
We have already discussed in detail the Lubricating Oils Vs. Lubricating Greases. Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil.
Lubricating greases are used to lubricate mechanical systems & tools that cannot be automatically supplied with oil. Greases are applied to mechanisms that can be lubricated infrequently and where a lubricating oil would not stay in position. They also act as sealants to prevent water ingress.
Lubricating Grease = Base Oil + Additive + Solid Lubricants + THICKENER.
So, now most probably you have understood why & where we can use greases & why we will not be able to use lubricating oil in every application. Hope you have liked our article.
Do share with your colleagues & friends who are always eager to learn something new about lubrication.