Shenzhen Wuge Industrial Co., Ltd

Nickel titanium wire is an alloy material with shape memory properties, widely used in aerospace, medical equipment, mechanical manufacturing and other fields. The heat treatment temperature and color have a significant impact on its performance and application.

Nickel titanium wire will exhibit different colors at different heat treatment temperatures, and the following is a rough correspondence:

200-300 ℃: Generally, a light yellow color will appear. In this temperature range, some microstructural changes begin to occur in the nickel titanium wire, but the overall performance changes are relatively small. The color change is mainly due to the formation of the surface oxide film, which is thin and causes light interference, resulting in a pale yellow color.

300-400 ℃: The color will gradually turn golden yellow. As the temperature increases, the thickness of the oxide film increases, the interference effect of light is enhanced, and the color gradually changes from pale yellow to golden yellow. At this point, the shape memory performance and superelasticity of nickel titanium wire begin to show significant changes, and the internal organizational structure is further adjusted.

400-500 ℃: May appear purple. This is because the thickness of the oxide film further increases, and the interference of light enhances the reflection of specific wavelengths of light, resulting in a purple color. In this temperature range, the performance of nickel titanium wire changes significantly, such as hardness, elastic modulus, etc., and the shape memory effect is also optimized.

500-600 ℃: Blue color usually appears. When the temperature reaches this range and the thickness of the oxide film reaches a certain level, the interference of light causes strong reflection of blue light, resulting in the appearance of blue. At this point, the performance of nickel titanium wire is basically stable, but excessive temperature may cause its grain size to grow, affecting its overall performance.

It should be noted that these color changes are not absolute and can be influenced by various factors, such as the surface condition of nickel titanium wire, heat treatment environment (such as atmosphere, heating rate, etc.), and insulation time.

In practical applications, the selection of heat treatment temperature and color requires comprehensive consideration of the specific requirements, material properties, and process conditions of nickel titanium wire. By observing color changes and experimental data, the heat treatment process can be optimized to ensure the performance and quality of nickel titanium wire.

In short, the correct selection of heat treatment temperature and observation of color changes are key to achieving shape memory effect and mechanical performance optimization of nickel titanium wire.