J Fail. Anal. and Preven. (2010)10: 399-407 (b) (c) L SOumI Fig 2 Macroscopic nce of stainless steel belt: (a) original one.(b) fractured or Fig 3 Metallographic structure of fractured stainless steel belts cross section: (a) cross section 100x,(b)center of cross sec tion 500x, and(e)surface of stainless steel belt Table 1 Chemical compositions of original and fractured stainless steel belts (wt % Ele AISI 301 <0.15 2.00 <0.045<003016.0~18.0 6.00~8.00 AISI 304 <0.045<0.03018.0~20.0 8.00~10.50 AISI 316L <0.03 ≤1 <0.045<0.03016.0~1802.00~3.001200~15.00 0.11050.7246 l.0432 0 031717.2484 0.1585 6.7737 Original one(polished) 0.1581 6.783 Original one(unpolished) 0.10920.7633 02120.00070.026717.03540.1602 Normal one after 4-month use 0.0 0.719 0.00340.00416 It is well known that 300 series stainless steels com- section of the failed stainless steel belt is a mixture monly exhibit austenitic microstructures. However, as it is microstructure of both austenite and martensite which has a shown in Fig 3, metallographic structure of the cross twisted fibrous morphology. Generally speaking, the SpringIt is well known that 300 series stainless steels com￾monly exhibit austenitic microstructures. However, as it is shown in Fig. 3, metallographic structure of the cross section of the failed stainless steel belt is a mixture microstructure of both austenite and martensite which has a twisted fibrous morphology. Generally speaking, the Fig. 2 Macroscopic appearance of stainless steel belt: (a) original one, (b) fractured one, and (c) fracture Table 1 Chemical compositions of original and fractured stainless steel belts (wt.%) Element C Si Mn P S Cr Mo Ni AISI 301 B0.15 B0.75 B2.00 B0.045 B0.030 16.0*18.0 / 6.00*8.00 AISI 304 B0.08 B0.75 B2.00 B0.045 B0.030 18.0*20.0 / 8.00*10.50 AISI 316L B0.03 B1.00 B2.00 B0.045 B0.030 16.0*18.0 2.00*3.00 12.00*15.00 Failure one (polished) 0.1105 0.7246 1.0432 0.0026 0.0317 17.2484 0.1585 6.7737 Original one (polished) 0.1103 0.7223 1.0411 0.0027 0.0320 17.2311 0.1581 6.7831 Original one (unpolished) 0.1092 0.7633 1.0212 0.0007 0.0267 17.0354 0.1602 6.4379 Normal one after 4-month use 0.019 0.719 0.94 0.0034 0.004 16.40 2.17 10.05 Fig. 3 Metallographic structure of fractured stainless steel belt’s cross section: (a) cross section 1009, (b) center of cross sec￾tion 5009, and (c) surface of stainless steel belt J Fail. Anal. and Preven. (2010) 10:399–407 401 123