Effective lubrication is the essential for the normal operation of the bearing. do you take the harm of moisture to the bearing seriously ?In fact, moisture has a great influence on the life of the bearing. Even little water (close to 500ppm) will decrease the life of a rolling bearing.

The harm of moisture reflect from two aspects: direct damage to the metal surface and damage to the lubricating grease, the latter leads to servere damage for a bearing indirectly .

Moisture will cause rust on the metal surface. For lubricating oil and grease, moisture will cause the oxidative deterioration of the base oil in the oil, and the oxidation products will come into contact with water again, and then generate acidic substances to corrode the metal. In addition, the water causes the oil to oxidize and deteriorate, generating oil sludge, which affects the viscosity and normal fluidity of the oil, further causing lubrication problems. Therefore, the beginning of the whole problem is only a small amount of water, causing a cascading effect, and finally accumulating into a big harm. This article discusses the harm of water to bearings and the consequences and phenomena caused by moisture through nine aspects.

  There are several ways to harm water to bearings:

 1. Hydrogen-induced cracking:

 It is lso known as hydrogen embrittlement or hydrogen damage, it can cause metal damage, but it has not received widespread attention in bearing manufacturing and maintenance. For such cases, water may be a part of the source of hydrogen. Electrolysis and corrosion will also produce hydrogen. Water will Promoting electrolysis and corrosion, high-strength steel is particularly susceptible to this problem. In addition, additives added to lubricating oils and greases contain sulfur (extreme pressure additives, antiwear agents, etc.), and mineral oil itself also contains certain sulfur impurities, which will promote corrosion and cracking of metals. Humid atmosphere and free water may cause hydrogen embrittlement of metals.

2. Corrosion:

  Water can cause metal rust and corrosion. After the corrosion damage is formed on the surface of the bearing raceway, the smoothness of the lubricating oil film is destroyed, resulting in poor lubrication and further aggravating the damage.

3. Oxidative deterioration of lubricating oil:

Water will cause the base oil in the oil to oxidize and deteriorate. If high temperature and impurities (such as fine metal abrasive debris) are added, the oxidation rate will increase significantly. In addition, water will cause the loss and consumption of antioxidants in the lubricating oil, resulting in oxidative deterioration of the lubricating oil. The oxidation of lubricating oil will form acidic substances, paint film on the metal surface, and the viscosity of the oil will increase, resulting in metal corrosion, affecting metal cooling and the normal function of some components.

4. Additives in oil consumption:

The main ingredients in lubricating oils and greases are base oils, as well as some additives. In addition to antioxidants, there are other additives such as antiwear agents, extreme pressure agents, rust inhibitors, detergent dispersants, anti-emulsifiers, etc. Water will cause additives to hydrolyze, agglomerate, and lose. Some sulfur-phosphorus extreme pressure agents will denature in the presence of water, generate sulfuric acid or phosphoric acid, increase the acid value of the oil, and form a corrosive acidic environment.

5. Affect the normal flow of lubricating oil:

  Water will cause emulsification of sludge and oil. These clumps of impurities are suspended in the oil and affect the normal flow of the oil. In addition, these impurities will also accumulate in the oil supply hole of the bearing. Other hazards are clogged filter elements. In severe cold weather, the water in the oil may freeze, which also causes poor oil flow and lack of oil in the machine.

6. Increased foam:

Moisture will affect the surface tension of the oil, causing bubbles in the oil and increased foam on the surface of the oil. For ordinary oil, only 1000ppm of water in the oil, the foam problem will be very serious, the consequence is that the metal surface cannot form a complete A series of problems occur with the lubricating oil film: increased oil temperature, increased oxidation, metal cavitation, and poor oil flow will cause damage to the bearing. The air bubble problem sometimes also affects the normal operation of the oil flinger or oiler.

7. Influence oil film strength:

  Bearing lubrication is a layer of oil film formed between the two metal contact surfaces by oil that acts as a lubricant. The oil film separates the direct friction between the metals and protects the metal. If moisture enters the metal contact bearing area of the bearing, it will It destroys the integrity of the oil film and reduces the strength of the oil film. For heavy-load, low-speed bearings, this hazard is particularly obvious, which can cause fatigue fatigue, metal scraping, and cracking.

8. Breeding bacteria:

Water will breed bacteria, microorganisms and fungi. The main hazard of these substances is to affect the normal flow of oil. In addition, it will block the filter element and form corrosive substances, causing lubricating oil, grease rancidity, and deterioration. It will indirectly harm bearings by affecting lubrication.

9. Loss of lubricating oil and grease:

  Water will cause oil loss through scouring. In addition, some greases will soften when immersed in water. With water loss, the thickener used in some greases is not resistant to water, and will be lost during water scouring and splashing.

 DAC conclusion:  the harm of water to bearings is mainly reflected in a series of chain reactions. Therefore, do prevent water inflow from the source, and prevent grease and lubricating oil from contacting moisture during storage, transportation and use. Prevent water from entering the bearing.