In harsh environments, relatively small problems like corrosion in a bearing can stop multi-million dollar vehicles where they stand. SKF and Textron are betting that bearings made with high nitrogen corrosion resistant (HNCR) stainless steel technology can reduce downtime on a military landing craft.
Stainless steel bearings common in equipment made for harsh environments have long been regularly replaced to avoid seizing and freeze up. It’s typically costly to replace bearings buried deep inside equipment, so a team within SKF’s aerospace group that focuses on blank sheet engineering and cutting edge technology has used the material in a line dubbed MRC.
“This is one of the largest advances in bearings in a while,” said Laurie Olson, Specialty Marketing Manager at SKF USA Inc. “This is the first completely non-corrosive stainless steel used in a bearing.”
Textron is using the MRC line in a Ship-to-Shore Connector used by the U.S. Navy to move personnel and equipment. Textron received a $213 million detail design and construction contract in July 2012 to build a test and trial craft.
That contract has since been expanded to nine vehicles that use Textron’s Landing Craft Air Cushion technology to hover above the water and move onto shore. They will employ a fair number of SKF’s bearings.
“We’re providing 13 sets of bearings for the new model, which has been in testing for two years,” Olson said. “This meets all the load requirements and reduces corrosion so our bearings can meet the U.S. military’s 25-year lifetime requirement.”
SKF has made HNCR in very limited production for a few years, employing HNCR bearings in applications as diverse as cranes and ice cream production equipment. That’s now changing as SKF’s manufacturing teams improved production techniques and test results showed good results.
“This is now ready for prototypes and small lots; it’s something we haven’t been able to provide before,” Olson said. “This will not become a commodity item; you’re not going to open our catalog and see HNCR bearings.”
The material has been used in a crane used to move materials from ship to shore for over five years, much akin to the Navy application. In an ice cream hardening tunnel, bearing lifetime went from around a year to more than five years, according to SKF.