Process Improvements for Prevention Stain Defect (B49) on Hot Rolled Pickled & Oiled (HRPO) Product

by Eddy Rukman, Iwan Muliawan

Publisher - PT Krakatau Steel

Category - General Novel

Hot Rolled Pickled & Oiled (HRPO) is one of the high value added products of PT Krakatau Steel. In the last few years stain defect (B49) is always found on the surface of HRPO and this defect was ranked top. Some investigations have been done to identify this problem. This paper shows the process of identifying the root cause of the stain defects. It is found that the stain defect is formed due to the mechanism of corrosion on the steel surface that influence by atmospheric conditions. Factors that influence and trigger of the formation of stain defects are location coil placement in storage (N1 yard) and storage time (aging time). In order to avoid or reduce the potential for this stain defect, it had been recommended that the maximum aging time in storage yard is less than 20 days and coil have to be placed in a roofed storage

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