Abstract: The SUS430 stainless steel insulation plate in the combustion chamber of the gas water heater has a problem of color fading at high temperatures. To address this issue, firstly a simulation test on the color change of stainless steel was conducted. Using the CIELAB color measurement system, the surface chromaticity change law of SUS430 stainless steel under high-temperature oxidation was studied, and the phase composition and morphology of the surface oxide film in different oxidation states were characterized. Meanwhile, the corrosion resistance data of stainless steel under different oxidation states were obtained. By correlating the corrosion resistance of stainless steel with the surface color change state, the corrosion mechanism of stainless steel under high-temperature oxidation was revealed. Further improvements were made to the air-cooling cooling channel and the structure of the stainless steel insulation plate to reduce the surface temperature of the combustion chamber. After six months of wind pressure blockage durability tests, the reliability of the optimized insulation plate was enhanced, and the color fading problem no longer occurred.

Key words: SUS430 stainless steel, High-temperature color change, Air-cooled cooling