Stocking up on specialist bearings
Specialist supplier of miniature bearings, SMB Bearings, has introduced a new range of 316 grade stainless steel ball bearings to its catalogue. The 316 bearing variety has been specially selected for customers with applications operating in harsh environments, which the bearings can withstand thanks to their marine grade stainless steel construction. The bearings will find a home in food processing, chemical manufacture and pharmaceutical production as well as marine and other liquid process applications.
The 316 bearing range can withstand temperatures of up to 500 degrees centigrade (if supplied without cages) and is highly resistant to seawater, salt spray and many aggressive chemicals. The key difference between 316 stainless steel bearings and other stainless steel bearings is the addition of molybdenum to the metal – an alloy which drastically enhances the corrosion resistance of the bearing.
SMB Bearings supplies 316 stainless steel bearings with polyethylene, PEEK or PTFE cages – all of which provide excellent corrosion resistance to water, salt water and most chemicals. When used in either a PEEK or PTFE cage, the bearings can sustain temperatures of up to 250 degrees centigrade. What is more, bearings from this range can be used in cryogenic applications down to an impressive -250°C, depending on the cage material.
Bearings made with 316 stainless steel are ideal for the food and beverage industry where the bearings are washed down with aggressive chemicals that may corrode the more standard 440 grade stainless steel. 316 stainless steel cannot be hardened by heat treatment so the bearings are semi-precision and only suitable for low loads and speeds such as in conveyor applications. They are also used in marine applications that operate above the waterline, but can also be effective when the bearing is temporarily submerged, providing it is regularly washed down with clean water.
316 stainless steel relies on the presence of oxygen to regenerate the passive film on the surface of the steel and, as a result, 316 stainless steel is a less suitable option if the bearing is permanently submerged. This is more likely in marine applications than food applications. For example, in a low oxygen marine environment, when there is no flow of water, the bearing steel may be prone to pitting corrosion.
While the 316 range is ideal for use in harsh environments, the more commonly used 440 grade stainless steel bearings are more ideal for high load and high precision applications – however, 440 grade bearings may suffer from corrosion in particularly harsh environments where 316 grade stainless steel would survive.
SMB Bearings provide an in-house relubrication service to replace the standard lubricant supplied with 316 stainless steel bearings. A range of H1 food grade greases are available offering advanced resistance to washout by cleaning fluids and resistance to low and high temperatures.
More information about SMB Bearings’ 316 stainless steel bearing range and its bespoke relubrication service can be found on the company’s website. Alternatively, if you would like to speak to one of the technical experts at SMB Bearings, you can contact the company’s base in Oxfordshire on +44 (0) 1993 842 555.