Abstract: In order to understand the trace characteristics and formation mechanism of the color coated plate after heating in detail, it can provide reliable trace evidence for the fire control personnel to accurately identify the cause and point of fire in the fire scene. In this paper, the characteristics of the heat trace of the color coated plate are described and studied in detail by changing the temperature and holding time. The macroscopic trace of hot-dip galvanized color coated steel plate is mainly reflected in the change process of coating shape and color. The main process is that the coating does not change, the paint layer changes to light yellow, the powder paint layer cracks, the paint layer falls off, and the sample is completely black. It can help the fire investigators to judge the heat trace of the color steel plate more accurately by the change of the sample surface.

Key words: fire protection, hot- dip galvanized color coated plate, characteristics of heat trace, micro-morphology