Cleaning of Rolling Bearings

The purpose of cleaning rolling bearings is to remove the impurities inside the bearings, improve the cleanliness and facilitate the implementation of anti-rust technology; or before using the bearings, remove the original oil seal on the bearings by cleaning.

Materials for cleaning rolling bearings

The commonly used cleaning materials for rolling bearings are gasoline, petroleum solvent mainly composed of kerosene, alkaline water solvent and organic solvent mainly composed of carbon chloride.

Table 10-4 ~ Table 10-6 are the properties and formulations of common cleaning detergents.

Tables 10-7 to 10-9 are various cleaning detergents and their application methods.

Table 10-4 Performance of Gasoline for Cleaning

Project		Quality Index	Test Method
1	Appearance	Transparent
2	Smell	No irritating odor
3	Distillation range Initial distillation point (℃)(No less than) 50% distillate (℃) (not higher than) Dry point (℃) (not higher than)	80 120 180	GB/T255
4	Corrosion (copper sheet 50℃ 3h)	Qualified	GB/T378
5	Sulphur content (%)(not higher than)	0.05	GB/T380
6	Water-soluble acids or bases	Nothing	GB/T259
7	Mechanical Impurity	Nothing	GB/T511
8	Water Content	Nothing	GB/T260
9	Cleaning performance(No less than)	No. 120 gasoline
10	Acidity: mgKOH／100mL(not higher than)	1	GB/T258
11	Colloid: mgKOH／100mL(not higher than)	2	GB/T509

Table 10-5 Performance of kerosene for cleaning

Project			Quality Index	Test Method
1	Appearance		Transparent
2	Smell		No irritating odor
3		Flash point (closure) (℃)(No less than)	60	GB/T261
4		Corrosion (copper sheet 50℃ 3h)	Qualified	GB/T378
5		Sulphur content (%)(not higher than)	0.05	GB/T380
6		Water-soluble acids or bases	Nothing	GB/T259
7		Mechanical Impurity	Nothing	GB/T511
8		Water Content	Nothing	GB/T260
9		Acidity: mgKOH／100mL(not higher than)	0.1	GB/T264

Table 10-6 Formula of Alkaline Cleaning Solution

Composition of alkali solution	1	2	3	4
NaOH	3~4	-	2	1
Na₂PO₄	5~10	10	5	2
Na₃PO₄	-	5	-	3
Na₂SiO₃	-	0.2~0.3	10	0.2~0.3
Water	allowance	allowance	allowance	allowance

Table 10-7 Cleaning fluid formula and Application

Item	Cleaning fluid formula（%）	Function And Application	Usage method
1	NaOH 0.5~1 Na₂CO₃5~10 Sodium Silicate 3~4 Water allowance	Strong alkalinity, heated solution can clean mineral oil, vegetable oil and sodium grease. Suitable for deoiling of general steel body (Measuring tool , cutting tool industry)	(1) Dip or spray with hot solution (60-90 ℃) for 5-10 minutes (2) After rinsing in cold water and rust removal
2	NaOH 1~2 Na₂CO₃·NaHCO 5~8 Sodium Silicate 3~4 Water allowance	Strong alkalinity, heated solution can clean mineral oil, vegetable oil and sodium grease. Suitable for deoiling of general steel body (Measuring tool , cutting tool industry)	(3) Dip or spray with hot solution (60-90 ℃) for 5-10 minutes (4) After rinsing in cold water and rust removal
3	Na₃PO₄ 5~8 NaH₂PO₄ 2~3 Sodium Silicate 5~6 R-C6H4-SO3Na 0.5~1 Water allowance	The alkalinity is weak, the heated solution has the ability to remove oil, and the corrosiveness to metals is low. Suitable for steel and aluminium alloy parts	(5) Dip or spray with hot solution (60-90 ℃) for 5-10 minutes (6) After rinsing in cold water and rust removal
4	SDBS 0.5 C24H49NO4 3 C6H5CO2Na 0.5 Water allowance	The alkalinity is weaker, and the heated solution can remove grease. Suitable for finishing and polishing of steel and aluminium alloy parts	Wash it in a solution heated to 90 ℃, then rinse it with rust-proof water.

Table 10-8 Petroleum Solvents for Cleaning and Their Use

Material and formula	Function And Application	Usage method
Solvent gasoline (commonly used 120, 160, 200)	Used for cleaning and degreasing of steel, iron and non-ferrous metal parts. Because of the rapid volatilization, the surface temperature of the workpiece drops sharply, and condensates easily in the humid weather.	General soaking or scrubbing, large-scale production of 200 solution gasoline, spray cleaning machine, cleaning times as required for 1 to 4 times
Replacement Antirust Oil of 2%~3% for Antirust Gasoline in Solvent Gasoline	Cleaning and rust resistance are better than gasoline alone. It can be used for pre-assembly cleaning of precision bearings.	Rust-proof gasoline soaking--solvent gasoline washing--alcohol washing--solvent gasoline washing, and then assembly
No.200 Solvent Gasoline 94% RSO₃Na 1% Span-80 1% SDBS 1% 1% Alcohol solution of benzotriazole 1% distilled water 2%	It has stronger cleaning power than gasoline alone. It can clean sweat, inorganic salts, grease and has short-term rust-proof effect on steel and copper. It is mainly used for ultrasonic cleaning of precision products before loading.	The main process of cleaning parts with ultrasonic cleaning machine is as follows: soak once with the prescription antirust gasoline - once with the same antirust gasoline - and then soak once with the antirust gasoline. Dirty gasoline should be replaced
Kerosene or light diesel	Volatilization is slower than gasoline, and trace is often left after volatilization. For general product cleaning.	It can be soaked, scrubbed and sprayed.

Table 10-9 Hydrocarbon chloride Solvents and Their Use

Material and formula

Function And Application

Usage method

Trichloroethylene (industrial use, adding 0.1%~0.2% stabilizer, such as diethylamine, triethylamine, pyridine, tetrahydrofuran, etc.)

It is volatile, non-flammable and does not allow air to form explosive mixture, but it has certain toxicity and needs ventilation (the permissible concentration in the atmosphere is 50mg/m3). Degreasing ability is strong, suitable for steel parts degreasing, such as steel sealing degreasing, heat treatment degreasing, oil avoidance product cleaning, etc. Usually recycled or recycled

The trichloroethylene cleaner is used for cleaning. The cleaner is divided into single groove type and multi groove type.

Single groove type: General steel parts can be removed grease after cleaning in gas phase for 5 to 8 minutes. Multi-trough type: after soaking or spraying for 1-2 minutes, then gas phase cleaning for 5-8 minutes

carbon tetrachloride

Strong degreasing power, often used in a small number of oil-avoiding products parts degreasing

Cold immersion and scrubbing can be done. Dry immediately after washing to prevent condensation.

Cleaning Method of Rolling Bearing

The cleaning method of cleaning material is selected according to the degree of bearing pollution and the type of pollutants. Commonly used cleaning methods are manual cleaning, mechanical spray cleaning, ultrasonic cleaning and steam cleaning. Mingwei adopts Ultrasonic cleaning to improve the cleaniness of the bearings.