A largest steel manufacturing company in Indonesia and it places a premium on quality to ensure customer satisfaction. This research intends to identify the elements that contribute to the occurrence of defective products in order to develop a plan for reducing defective products in production outcomes. To quantify the degree of product defects in this study, the Six Sigma approach was utilized, which consists of Define, Measure, Analyze, Improve, and Control (DMAIC). The study focuses on common flaws seen in Hot Rolled Coil (HRC) products. According to the calculations, the three most common fault types are telescope, wavy, and chamber. The idea is presented as an attempt to improve in order to reduce the number of defective items. The findings of this research can be utilized to assess defective items and make modifications that the corporation can implement.