Marine grade 316 stainless steel ball bearings for shafts from 3mm to 50mm diameter
See product table below for dimensions and technical drawings
Marine grade 316 stainless steel ball bearings are available in a range of sizes, accommodating shaft diameters from 3mm to 50mm. These high-quality bearings are specifically designed to excel in challenging marine environments, making them a top choice for various applications both above and below the waterline.
316 grade stainless steel, known as marine grade stainless steel, is an austenitic stainless steel grade which means it has excellent corrosion resistance. Unlike 440 grade martensitic stainless steel, 316 grade is not hardenable by heat treating. As a result, 316 stainless steel has a much lower load capacity than the standard 440 grade stainless steel most commonly used for bearings.
This softer grade of steel is more difficult to grind to very close tolerances than chrome steel or 440 stainless steel so, like plastic bearings, marine grade 316 bearings are semi-precision. Unlike the strongly magnetic 440 grade stainless steel bearings, 316 stainless steel bearings have a negligible response to magnetic fields so it is possible to tell the two types apart with a magnet.
Corrosion resistant bearings can also be supplied in synthetic materials or zirconia or silicon nitride. For more information on bearings for harsh environments, see our informative guide. Most of our range of marine grade bearings are supplied from stock in the UK.
The 316 grade bearings, shown in the table below, are highly resistant to seawater, salt spray and many aggressive chemicals. The standard range is supplied with polyethylene (PE) cages and seals but alternative cage and seal materials such as PEEK or PTFE can be offered.
Applications for 316 stainless steel bearings
316 stainless steel bearings are used in low load and low speed applications in the marine industry when used above the waterline or where the bearings can be washed down after temporary submersion in salt water. They can be immersed in seawater for longer periods if there is a regular flow of water over the bearings as oxygen helps to regenerate the steel.
These bearings are found in the food and beverage industry, in bakeries and fish or meat processing plant as well as in the dyeing industry, the textile industry, the pharmaceutical industry and the paper industry.
316 stainless steel has a very wide temperature range. The cage and seals will limit the temperatures at which these bearings can be used but open, full complement 316 grade bearings can withstand temperatures as low as -200°C and as high as 500°C although the load capacity is reduced at more extreme temperatures.
For cryogenic applications, full complement 316 grade bearings with PTFE cages and seals are suitable, as PTFE exhibits excellent low-temperature performance down to -190°C. However, it's essential to note that the standard PE cages and seals are not recommended for temperatures below -40°C or above 80°C. For high-temperature applications, PEEK or PTFE cages and seals can be utilised, withstanding temperatures up to 250°C.
In our product table below, you'll find a comprehensive list of 316 grade stainless steel bearings with technical drawings, load, and speed data. Please note that the maximum loads and speeds are used in theoretical life calculations. It is recommended to use bearings at significantly less than the maximum load and speed ratings to ensure reasonable bearing life.
For more information about our range of 316 stainless steel bearings email sales@smbbearings.com.