This is an explanation of how when steel heats up it changes color. This is very important to a blacksmith because it is how the smith knows what the temperature of the steel is. And with changes in temperature come changes in properties.

So a blacksmith very carefully watches the changing color of steel as it heats.

I also have a video showing you all of this at the bottom of the page.

Will has a youtube channel with over 700 videos on projects you can make including dozens of blacksmithing videos. Check it out right here

About steel, heat and colors

Steel is an amazing thing. We think of it as being as hard as well... steel. We have that phrase for a reason. But, steel has a large spectrum of properties. For example, it can be so hard that it is brittle, almost like glass and easily broken or cracked. Would that make for a good sword or a good knife? No!

And we all know that a blacksmith heats up steel in a forge and then hammers it into shapes. But how hot should it be? Can a smith heat it to 100 degrees and then hammer it? No! This would do nothing at all to the steel. So, how does the smith know how hot it is?

These two questions are fundamental to the art of blacksmithing and these questions are both answered by the color of the steel when it heats up. And steel changes color as it heats up so a smith can get a reasonably good estimate of the temperature of hot steel simply by observing the color.

Two Major tasks of a blacksmith

Blacksmiths do a lot of things but when it comes to heating up steel there are two major tasks.

First, the smith has to heat the steel to a temperature high enough so that it can be worked on with hammer and tools.

Secondly the smith has to heat the steel so it is at a temperature that is suitable for the end use of the item.

Let's heat up a piece of steel and take a look.

This first picture shows you tempering colors. The steel is only heated a small amount. At tempering colors the steel is softer and more resilient. It has some give to it. It will flex slightly when under use. The blacksmith brings steel up to these colors/temperatures when he wants to get steel to a property that is suitable for use by the end user.

And now I have left the steel in the forge longer and it is a whole lot hotter! At these higher temperatures the steel is ready for hammering and shaping. The blacksmith bring it up to these colors so he can work on it.

This chart shows you the ranges.

Feel free to share this heat chart on your website or blog: Copy and Paste the code:

Video Here

Do you like making projects and exploring a variety of hobbies?

Sign up for my free newsletter. I give you regular updates on hobbies and projects you can make. it is totally free and I don't share your email with anybody.