Bearing used in offshore engineering needs to deal with the corrosion risk that always exists. Due to the corrosive force of seawater, the selection of bearing needs to balance the load capacity and corrosion resistance to extend the service life of bearing.
Special bearings for ships
Corrosion-resistant bearing material
The bearing made of 440 stainless steel has certain resistance to sea water or salt spray and has strong corrosion resistance. It can be well used in the marine environment. At the same time, it can also improve its corrosion resistance by passivating the 440 stainless steel ball bearing,
In addition, the ball bearing made of 316 stainless steel bearing can be used above the waterline or in flowing water.
The load and speed of 316 stainless steel bearing are lower than that of 440 stainless steel bearing of the same specification. However, it can be used in high temperature applications by replacing cage materials; In addition, 316 stainless steel bearing cannot be hardened by heat treatment, so it can operate intelligently under low load and low speed conditions.
The all-ceramic bearing is made of zirconia or silicon nitride material, which can provide high corrosion resistance in ship applications, and can be used in the application environment of long-term immersion in the sea, with higher hardness and higher load. However, the price of all-ceramic bearing is expensive, and it is more brittle than bearing steel, and it is easy to crack after receiving huge impact. In the environment that needs to bear heavy impact load, it is not recommended to use all-ceramic bearings.
The polyoxymethylene resin bearing with 316 stainless steel ball or glass ball has seawater corrosion resistance and can only be used in low load and low speed environment with low accuracy. Its capacity can be improved by PEEK and other alternative materials, and it belongs to semi-precision and low-load bearing.