How to use the spark test:

Not sure what material you've got? A spark test can answer your questions.
Get out your grinding wheel and use these photographs as a guide.

     Tungsten carbide, has a rockwell hardness of 88 to 90, second only to diamonds;
     its specific gravity is 16, almost as heavy as gold, twice as heavy as high speed steel.

     Tungsten carbide is very heavy and very hard; very hard is the basis of this test:

     If your scrap can only throw a very short, orange spark, it's tungsten carbide.

     If it sparks red/orange, 12 to 18 inches long, it is worth shipping to us.

     if it sparks long and white, it is not.

     We have listed specifications for many high speed steels on our hss spec page