Stainless steel begins to discolor at elevated temperatures starting at **430°F to 600°F (220°C to 316°C)** due to the formation of an oxide layer on the surface. This oxidation process results in a series of distinct colors depending on the surface temperature of the stainless steel.

The typical color progression and corresponding temperatures are:

1. **430°F to 600°F (220°C to 316°C)**: A light yellow or pale straw color starts to appear.

2. **600°F to 900°F (316°C to 482°C)**: The steel takes on a brown or bronze color.

3. **900°F to 1,100°F (482°C to 593°C)**: A purple or blue hue develops.

4. **1,100°F to 1,300°F (593°C to 704°C)**: A deep blue or gray color is observed.

5. **Above 1,300°F (704°C)**: The steel may turn a dark gray or black, with significant surface changes.

The thermal conductivity of 304 and 316 Stainless Steel of around ** 14 – 17 W/m-K **. For reference the thermal conductivity of hot rolled steel is ** 45-60 W/m-K**. The higher the thermal conductivity the more resistance the substrate has to discoloration in service. The goal of ZyCoat is to reduce the substrates’ ability to “absorb and retain” heat. ZyCoat technology has been proven at all levels. 

The application of ZyClear to the stainless steel surface lowers the oxidation rate and reduces the pace and amount of discoloration of the substrate. The effect is raising of the thermal conductivity of the stainless steel. This is a direct result of ZyClear’s heat dissipation properties and stainless steel temperature reduction.

The exact temperature at which discoloration begins can vary slightly depending on the type of stainless steel and its specific alloy composition, but this progression gives a general idea of the color changes that occur at various temperatures.

Bottom line, the ZyClear coated surface is causing the Stainless Steel to dissipate heat faster than an uncoated surface. This keeps the substrate surface from elevating in temperature and has a direct impact on the amount of discoloration.

** Substrate surface temperatures of exhaust headers on an internal combustion engine will reach the 400°-600° F surface level with ZyClear applied. Uncoated headers surface will elevate above 900° F.

Check out this video linked below from Summit Motorsports Park – Halloween Classic on Chris Schneiders Stainless Works SuperPro stainless headers. Also see related video from Gooichi Motors demonstrating their test results on ZyClear’s impact on titanium discoloration!