What causes rainbow color in heated steel?

In summary, the conversation discusses the appearance of rainbow colors on stainless steel samples that have been exposed to high temperatures. This is caused by the thin oxide layer on the steel, which creates interference effects for different wavelengths of light. The colors in different areas of the sample indicate varying temperatures, and this phenomenon is similar to Newton's rings seen in thin oil films on water. Further information can be found on tempering colors in metallurgy.
  • #1
bigfooted
Gold Member
680
211
Hi,

This question came up after some stainless steel samples were exposed to high temperatures (metal flame holders in a combustion chamber). Some of them had areas with rainbow colors. What exactly happens to the steel that causes these local rainbows? If the colors in point A and B on the sample are different, does that mean that in point A the steel has been exposed to different temperatures than in point B?
 
Engineering news on Phys.org
  • #2

Related to What causes rainbow color in heated steel?

1. What is the main factor that causes rainbow color in heated steel?

The main factor that causes rainbow color in heated steel is the phenomenon of thin film interference. This occurs when light reflects off the surface of the steel and interferes with itself, resulting in different wavelengths of light being reflected and creating the appearance of different colors.

2. Can the thickness of the steel affect the rainbow color?

Yes, the thickness of the steel can affect the rainbow color. Thicker steel will produce larger spaces between layers, resulting in a wider range of colors being reflected. Thinner steel will have smaller spaces between layers, producing a more limited range of colors.

3. What temperature does the steel need to reach in order to show rainbow colors?

The temperature at which steel will exhibit rainbow colors varies depending on the composition and thickness of the steel. In general, the steel needs to be heated to a temperature high enough for it to glow red (around 600-700 degrees Celsius), but not hot enough to melt.

4. Why do different types of steel produce different rainbow colors?

Different types of steel contain varying amounts of different elements, which can affect the thickness and composition of the thin layers that cause the rainbow colors. This results in different colors being reflected at different temperatures for each type of steel.

5. Can the presence of impurities in the steel affect the rainbow color?

Yes, the presence of impurities in the steel can affect the rainbow color. Impurities can alter the composition and structure of the steel, which can change the thickness of the layers and the resulting colors that are reflected. This is why different batches of the same type of steel can produce slightly different rainbow colors.

Similar threads

Research question about burning metals and their flashes and colors
    • Materials and Chemical Engineering
Replies
12
Views
2K
What if Luders Bands do NOT show up as expected?
    • Materials and Chemical Engineering
Replies
1
Views
1K
What is the Cooling Time for Steel Tubes with Ambient Nitrogen Gas Flow?
    • Mechanical Engineering
Replies
7
Views
2K
What caused the Quadruple Rainbow?
    • Other Physics Topics
Replies
6
Views
3K
On-demand steam engine idea
    • Mechanical Engineering
Replies
13
Views
360
Torsional strength at high temperature
    • Materials and Chemical Engineering
Replies
2
Views
1K
Difference between cast iron and high carbon steel?
    • Chemistry
Replies
3
Views
5K
Understanding Flame Tests: Exploring Sodium and Chloride
    • Chemistry
Replies
6
Views
2K
What is the best material for cryo ball mill cup assembly?
    • Materials and Chemical Engineering
Replies
9
Views
2K
I Processes that determine the color of fire
    • Other Physics Topics
Replies
10
Views
2K

Hot Threads

Recent Insights

Back
Top