CQI (Continuous Quality Improvement) in the field of heat treatment of metals is a set of standards and guidelines focused on the continuous improvement of quality in heat treatment processes. These standards are specified by the AIAG (Automotive Industry Action Group) under the CQI-9 guidelines, which are primarily intended for the automotive industry and establish requirements for controlling, monitoring, and managing heat treatment processes. The goal of CQI-9 is to ensure that heat treatment is conducted in accordance with strict quality standards.