Fault Diagnosis and Root Cause Failure Analysis of Press Roller Mill for Heavy Industry

摘要

This case study is to identify and evaluate the root cause for failure of a roller press mill. Cement plant has a heavy crushing operation the roller's top surface is eroded, which is replaced by hard metal deposition by welding. In manufacturing, most of the steel metals are failing by either fatigue or by hard deposition through welding. In this case, repair welding has been used for several years. But there is no specific welding procedure adapted to repair the large size of the rolling parts as it is very difficult to operate in that situation and constraints of the welding operation. In this connection, the plant was inspected, their log book was verified, and the complete procedure of welding was checked. Further study was done by cutting the small piece of the press roller mill's material by using diamond abrasive cutter and it was used to prepare the test specimen using wire cut EDM. Further composition of the welding rod and base material were found by SEM study. Subsequently, their hardness values were also measured. From this study, it is concluded that the welding procedure was not followed properly and oxidation took place during the time of weld, because of the large variations of the weldability of the material over the surface of the base metal and also the presence of blue patches in the weld metal during SEM analysis.