How to Recognize Carbide

Carbide is a compound that is formed from carbon and another metal, typically tungsten, although there are many types of carbides, all with slightly different properties. Carbide is noted for its strength and durability and is often used in parts for tools. Because it is designed for durability, carbide has some fairly unique characteristics and determining if an item is made from carbide is not very difficult. Learning to distinguish carbide from other materials can be a valuable skill, as recycling carbide is fairly profitable. 

Instructions

1.Hold a magnet to the item you are examining. If the magnet is attracted to it, the item is not carbide, it is iron or steel. However, sometimes carbide is used as a tip for an item, particularly saw blades, so this test is sometimes misleading.

2.Pick up the item and "heft" it. Carbide is very dense, and a carbide object will feel very heavy relative to its size. If you have a piece of steel that is a similar size to the object you are inspecting, the item will weigh about twice as much as the steel if it is carbide. This is the most conclusive test that does not risk damaging the item you are examining.

3.Scratch the item with a steel nail. The Mohs hardness scale is a method of measuring the hardness of different materials. Steel has a Mohs hardness that ranges between 5 and 8.5. Carbide will range between 8 and 9, depending upon the exact alloy that the carbide is made from. Typically, carbide will scratch steel and will not be scratched by steel. Carbide will scratch glass as well, as another way to test its hardness.

4.Examine the item. Carbide does not corrode under normal conditions and does not rust. Seeing either of these indicates that the item is made from some other metal.

5.Put the item to a grinder and watch the sparks. Sparks from carbide are short and dark red, and are very distinctive to carbide. This is a fairly definitive test, but is somewhat more dangerous than other methods of identification and can damage the item.