There is a way to determine the kind of steel you have on hand. This can be done by spark testing, an ancient art recently developed into a modern industrial science. This art enables one to determine not only the metal's chemical composition, but also the characteristics taken on by steel due to decarburization and heat treatment.
Sparks are emitted when a piece of metal is touched to a grindstone. Fast, nondestructive and accurate, spark testing detects the presence of most alloying elements in the metal. A high-speed portable hand grinder is used. Its two-and-a-half-inch (6.3-centimeter) abrasive wheel is capable of reaching 15,000 to 20,000 revolutions per minute without breaking up. The grinding wheel should be dressed clean before a person begins spark testing. Otherwise, there may already be steel particles on it that will give misleading results.
Constant pressure between the grinding wheel and the steel sample is very important. This pressure should be sufficient to produce a spark stream about two feet long.
Those sparks reveal the unknown to the trained eye. In the stream of sparks each element produces its own particular pattern and individual color. The amount of an element present in the steel is determined by observing the frequency of its characteristic spark. So it is possible to detect the presence of such elements as carbon, manganese, silicon, nickel, chromium, molybdenum, tungsten, copper, aluminum, titanium, vanadium and columbium.
Sparks are emitted when a piece of metal is touched to a grindstone. Fast, nondestructive and accurate, spark testing detects the presence of most alloying elements in the metal. A high-speed portable hand grinder is used. Its two-and-a-half-inch (6.3-centimeter) abrasive wheel is capable of reaching 15,000 to 20,000 revolutions per minute without breaking up. The grinding wheel should be dressed clean before a person begins spark testing. Otherwise, there may already be steel particles on it that will give misleading results.
Constant pressure between the grinding wheel and the steel sample is very important. This pressure should be sufficient to produce a spark stream about two feet long.
Those sparks reveal the unknown to the trained eye. In the stream of sparks each element produces its own particular pattern and individual color. The amount of an element present in the steel is determined by observing the frequency of its characteristic spark. So it is possible to detect the presence of such elements as carbon, manganese, silicon, nickel, chromium, molybdenum, tungsten, copper, aluminum, titanium, vanadium and columbium.
