Spark Test: Identification of Iron and Steel

The spark test is a simple method to get a very crude idea of the carbon content of a piece of steel. With a little practice, you can get pretty good at identifying mild steel vs. a high carbon steel. What you have here, is the simple fact that the sparks given off by a piece of steel or iron can be used to identify the material.

The process: either gently touch the piece of steel in question (clamped in a vice) with a angle grinder or gently touch the steel to a bench grinder and observe the spraks given off. Ideally you want to do this in low light so that you can better observe the sparks. The more forking and stars that you see, the higher the carbon content. Next you compare the sparks from your mystery metal with the sparks from a know steel. It is important to try and apply the same amount of pressure to both exemplars.

It is very easy to differentiate wrought iron from steel and to tell between low, medium and high carbon steel.

If you want to add this process to your diagnostic tool kit, you should start collecting small pieces of known steel. As you collect them, permanently mark each piece. It is handy to either drill or punch a hole so that you can string your known samples on a wire ring.

Some beginner's books have pictures of the sparks coming off of various different types of steel. Also, if you GOOGLE: "SPARK TEST" you can find a number of pictures and drawings describing the sparks given off by various metals.

-- AlbinDrzewianowski - 09 Aug 2009