J Fail. Anal. and Preven. (2012)12: 427-437 Table 1 Chemical compositions of the failed roller bearing (wt %o) Elemen Si Mo Outer ring 0.85l 0.314 0.007 0.009 0.269 0.137 1.751 0.186 0032 0.187 GB/T GCr15095-1050.15-0.35<0.025<0.0250.25-0.450301.401.65<0.10<0.25 AISIE521000.98-1.100.15-0.30<0.0250.025025-0.45 1.30-1.60 (b)R (c) Fig 3 Metallographic structures of the failed roller bearing:(a) outer ring, x500.(b)roller, x500, and(e)cage, x10 greases owing to excessive operational temperature of the exhibits relatively smooth, but contains some traces of bearing. Achievements of this article have critical impor- friction, Fig. 2d. tance in prevention of such failures on the cylindrical roller ngs running under similar operatic Matrix Material Examination Chemical Compositions Experimental and Results Chemical compositions of the matrix materials of the outer Visual observation ring and the roller of this failed roller bearing are listed in Table l, and are also compared with the requirements of Figure 2a presents the location of this fracture, i.e., on the GCr15 bearing steel in GB/T 18254-2002 standard of China bottom of the outer ring of the roller bearing. Moreover, it (approximately equals to AISI E52100). It is obvious that can be learnt from Fig. 2b, c that this fracture is straight, except silicon, other elements in the roller are all qu even crossing the thickness of the bearing. Its fractograph according to the specifications. However, as for the outer Springgreases owing to excessive operational temperature of the bearing. Achievements of this article have critical impor￾tance in prevention of such failures on the cylindrical roller bearings running under similar operation conditions. Experimental and Results Visual Observation Figure 2a presents the location of this fracture, i.e., on the bottom of the outer ring of the roller bearing. Moreover, it can be learnt from Fig. 2b, c that this fracture is straight, even crossing the thickness of the bearing. Its fractograph exhibits relatively smooth, but contains some traces of friction, Fig. 2d. Matrix Material Examination Chemical Compositions Chemical compositions of the matrix materials of the outer ring and the roller of this failed roller bearing are listed in Table 1, and are also compared with the requirements of GCr15 bearing steel in GB/T 18254-2002 standard of China (approximately equals to AISI E52100). It is obvious that except silicon, other elements in the roller are all qualified according to the specifications. However, as for the outer Table 1 Chemical compositions of the failed roller bearing (wt.%) Element C Si S P Mn Ni Cr Mo Cu Outer ring 0.851 0.314 0.007 0.009 0.269 0.137 1.751 0.193 0.186 Roller 0.964 0.583 0.009 0.011 1.064 0.125 1.464 0.032 0.187 GB/T GCr15 0.95–1.05 0.15–0.35 B0.025 B0.025 0.25–0.45 B0.30 1.40–1.65 B0.10 B0.25 AISI E52100 0.98–1.10 0.15–0.30 B0.025 B0.025 0.25–0.45 1.30–1.60 Fig. 3 Metallographic structures of the failed roller bearing: (a) outer ring, 9500, (b) roller, 9500, and (c) cage, 9100 J Fail. Anal. and Preven. (2012) 12:427–437 429 123