Bearings for the Steel Industry - NSK Europe - #19

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Steel Industry 19 Identification of failure User Benefit Material measures Design measures Development of SWRTM Bearings Development of wear-resistant materials ›› Selection of steel chemical composition ›› Applied special heat treatment technology ›› Controlled optimum level for retained austenite Microstructure: Result P-extraction replica work using transmission electron microscopy (TEM) AISI 52100 SWRTM Basic performance Profile of wear on the outer ring raceway surface of Spherical Roller Bearings Countermeasure (1): Wear resistance Evaluation of an endurance test using 22210CD bearings AISI 52100 21 mm Maximum wear depth: Approx. 17 ìm Rolling position Rolling position Rolling position Rolling position Maximum wear depth: Approx.5 ìm 10 ìm 10 ìm 21 mm SWRTM Wear resistance approx. 3 times Countermeasure (2): Improved flaking life (inhibition of flaking) Evaluation of operating life by thrust-type life test Bearing life approx. 5 times Core toughness approx. 5 times Countermeasure (3): Improved outer ring strength Evaluation of outer ring strength Core fracture toughness KIC, MPa·m½ Field endurance evaluation Roller apron (R/A) Pinch rolls (P/R) Longer bearing life results in extended segment replacement cycles SWRTM Bearings allow users, who have been forced to replace segments at frequent cycles due to the bearing life of standard spherical roller bearings, to attain maximum effect in reducing maintenance, by decreasing unexpected accidents and using rolls to the full extent of their operating life. Standard Spherical Roller Bearings CASE 1 and 2* SWRTM Bearings CASE 1 and 2* Ø Average segment replacement cycles: 1 Ø Average segment replacement cycles: 1.6 Maximum: 2 * see case 1 and 2 on pages 16-17