why is different grease with different colors?

Colorants in greases are used only to identify greases and make them more noticeable than brown or black.It is because of this that grease has different colors, which can help users find the wrong grease and different kinds of grease.（For example, as the following three pictures, you can easily distinguish the difference between grease）

The color of grease can also reflect its overall quality.When grease degrade and become contaminated, they usually begin to darken.When the color darkens significantly compared to the new grease, it may be a sign that the grease has reached its scrap limit.While the darkening of the grease's color should not come as a surprise, the rate at which it darkens is an important factor.

In addition to dimming the grease due to operating and environmental conditions, a color shift may be a sign that the grease accidentally mixes with different types of grease.If this happens, immediate action should be taken to determine how and why it happened.Careless use of the wrong grease is more common than most people realize.

A quick solution is to use different types of grease for different types of fittings.The other is to leave a residue of grease in the grease to mark the appropriate color.There is only a single type of specific color grease on the equipment, which is the thing to do.（For example, red grease is smeared on the motor bearings to facilitate the distinction）

When the color of the grease has the potential to provide quality information, it is used only as a brand to indicate the type of grease (usually the thickener type).However, no grease color is guaranteed to specify a particular thickener, even in a single lubricant manufacturer's product.

The following table shows that the color of a particular grease may be several different types of greases, especially in composite lithium based greases

These issues have been discussed many times by different grease experts and grease websites.

Discussion on the cause and harm of lubricating grease drying and hardening

What is the cause of dry grease?

1. the grease is contaminated: dust, soil, floating dust and similar impurities, which will cause the grease to dry.

2. Incompatibility between grease: if you do not carefully mix the grease, it will also destroy the colloidal structure of the grease and accelerate oil separation.One of the typical examples is the blending of organobentonite greases with soap-based greases.

3. high temperature volatilization: the use of low viscosity base oil deployment of grease is the most volatile.When the temperature rises to a certain height, the base oil spills out of the thickener and the grease gradually hardens (the ratio of base oil content to thickener decreases and the viscosity of the base oil increases).

4. Oxidation of base oil: base oil looks like asphalt after oxidation, and grease will undergo the same oxidation process.

5. overheating of machine parts: such as excessive grease filling of bearings, overheating caused by mechanical conditions (improper installation, excessive load, etc.), insufficient lubrication may cause overheating in the operation of the machine, among which, too much grease filling is a common incentive.When the machine runs at high temperature and reaches the drop point of grease, the oil begins to precipitate out, the grease gradually loses the base oil and starts to dry, and finally the grease fails, and the machine will have problems.

What are the hazards of dry grease?

After the grease is dry, it will cause obstruction, cause poor lubrication of the system, and the machine will run too hot, increase the friction resistance of mechanical components when lubrication, and increase the consumption of mechanical power. It will damage the bearing and cause bearing breakage. As shown in the picture below!

Once the grease dries and causes blockage, the thickener will stay in the machine and the base oil will be lost.In the centralized lubrication system, the dry grease blockage is more likely to occur in the pipeline between the oil pump and the nozzle.In order to prevent the dry blocking problem of grease, the choice of grease is very important. The oil distribution trend of good quality grease is low. In addition, we should pay attention to keep the flow rate of grease enough to prevent the grease from being in a static state, because it will induce oil distribution and blockage. The world famous grease bearing manufacturer also gave a similar answer in this article。