Showdown in the test laboratory: Plastic ball bearing competes against metal bearing in saltwater test

2-hole flange bearing made of metal and xiros flange bearing made of xirodur B180 after the saltwater test in the test laboratory. No corrosion or discoloration is visible on the wear-resistant xiros bearing with online calculable lifespan. (Source: igus GmbH)

igus operates the world's largest plastics testing laboratory for moving applications in Cologne. Over 12,000 tribological tests are conducted annually by the motion plastics specialist. These include experiments that examine the use of various materials in different environments in real-world tests. This time: xiros flange ball bearings and metal bearings in saltwater. By using maintenance-free and lubricating Tribo-Plastics, the xiros bearing fully convinced in the test.

The engineers at the igus test laboratory filled a container with seawater and heated it to +80 degrees Celsius. Then, two bearings were immersed for 120 hours: a classic 2-hole flange bearing made of metal and an xiros flange bearing made of xirodur B180 – a high-performance plastic that igus has optimized over years regarding wear and media resistance. Both bearings were not completely covered in the test but had contact with air to trigger the corrosion effect.

Metal bearing begins to corrode after a few hours

The test results spoke a clear language in the end. After only a few hours, the metal bearing began to corrode. By the end of the test, all bearing components showed clear rust traces. The plastic bearing, on the other hand, remained unaffected. The xiros flange ball bearing also showed no signs of the aggressive saltwater and high temperatures after 120 hours. No color change, no rust traces. A clear advantage, especially for cleanroom applications and applications in food and medical technology, where rust poses a hygiene risk. The xiros ball bearings typically consist of four components: the inner and outer rings, the plastic cage, and the balls made of stainless steel or glass. Unlike metal bearings, wear-resistant polymer bearings allow for particularly smooth and hygienic dry operation without a single drop of lubricant and are maintenance-free. Their high lifespan can be easily calculated online. Additionally, the plastic bearings are electrically insulating, temperature-resistant from -40 to +80 degrees Celsius, non-magnetic, and 60 percent lighter and up to 40 percent cheaper than comparable metal bearings. They are suitable for carrying medium loads and have been reliably used worldwide by users for years – including in conveyor belts, labeling, conveying, and packaging machines, as well as in filling plants.