Corrosion Fatigue Cracking in Paper Machine Felt Guide Roll Shafts

This work aims to determine the root cause of unexpected failures of felt guide roll shafts of a paper machine. This was executed by performing finite element analysis (FEA) and metallurgical failure analysis. For the FEA, computer simulations were performed to assess load-bearing behavior of the shafts during operation. For the failure analysis, various techniques were employed including visual inspection, chemical composition analysis by emission spectroscopy, fracture surface analysis, and microstructural analysis by optical microscopy (OM) and scanning electron microscopy (SEM). The FEA results show that the effective stress values in the shaft cracking regions are far less than the fatigue limit but cracking still occurred. This suggests that the material’s mechanical properties deteriorated due to corrosion. From the failure analysis results, it was found that corrosion fatigue was likely to be the root cause of the shaft failure incidents.