Can stainless steel ball bearings come into contact with corrosive substances?

Whether stainless steel ball bearings can come into contact with corrosive substances cannot be generalized, and specific conditions need to be strictly evaluated:

Material differences determine tolerance:
Common 304/316 stainless steel bearings have good resistance to weakly corrosive environments (such as ordinary humidity and some weak acids and bases), which is superior to ordinary carbon steel.
But its tolerance to strong corrosive media (concentrated acid, strong alkali, high concentration salt spray, halogen ions such as chloride ions) is limited. 316 is slightly better than 304, but pitting or crevice corrosion may still occur.
Special materials (such as 440C martensitic stainless steel) have high hardness but generally lower corrosion resistance than 304/316 austenitic steel.

The contact method and time are key:
Occasional, short-term, low concentration sputtering contact (such as equipment cleaning and flushing), well-designed bearings (with appropriate sealing) can usually withstand it.
Long term immersion, high concentration steam, or continuous exposure to corrosive media, even 304/316 stainless steel bearings are highly likely to corrode and fail.

Sealing protection is essential:
The structure of exposed bearing raceway is complex, with gaps, and corrosive media is easily infiltrated and accumulated, accelerating damage.
Effective sealing (such as FKM sealing rings made of fluororubber) is crucial in preventing media from entering the raceway, directly affecting the durability. If the seal fails, the bearing is difficult to maintain.

The type of medium has a huge impact:
Chloride ion environment: Stainless steel is prone to stress corrosion cracking and pitting, and special attention should be paid.
Reductive acids (such as dilute sulfuric acid) are more corrosive to stainless steel than oxidizing acids (such as nitric acid).
High temperature corrosive medium: An increase in temperature will sharply accelerate the corrosion rate.

Lubricants need to be synergistically protected:
Lubricants must be resistant to medium erosion and capable of forming effective isolation barriers on metal surfaces.
Incorrect lubricants can be washed away by the medium or fail to react, causing the bearing to lose protection.

Potential risks cannot be ignored:
Corrosion can damage the smooth surface of the raceway and ball bearings, leading to a significant increase in noise, vibration, loss of accuracy, and jamming and fracture.
Corrosion products contaminate media (such as in food and pharmaceutical applications, which pose great harm).