Metal Identification
In this Article we will learn how to identify metals; we do not need to welders to know this.
The first thing that we see when we check the metal is the surface, from that angle it is already possible to identify what kind of metal are we viewing. The surface color is a strong indicator of the metal, viewing it under metallurgical microscopes will give us a closer look and the color will differ under certain magnification. As what we mentioned earlier, the appearance of the metal in outside form can give us clue on our identification, however, the surface will not give us detailed information about the metal only its classification. Freshly cut or filed metals will give some distinct characteristics that will provide clues in classification. The marks left by the manufacturer can aid in the identification of metal, these marks sometimes appear to be very small and we need powerful metallurgical microscopes to view this. For easy identification of cast iron and malleable iron, you just need to check the presence of sand mold.
For low carbon steel only the forging marks can be seen however for high carbon steel you can see rolling marks or forging marks. Rolling marks and forging marks can be viewed distinctly under metallurgical microscopes. When we check the metal surface, we also need to feel the roughness or the smoothness of the surface for this can also give us some identification clue. An example given was the stainless steel on its unfinished state, in this case the surface is slightly rough compared to copper, brass, bronze, nickel and monel who happened to have smooth surface. Another metal that has a smooth surface is the lead however the appearance will somewhat look like velvet. If we fail to identify the metal its appearance and surface smoothness then we need to conduct the proper metal identification with the help of metallurgical microscopes and advice from metal experts.
The first test mentioned was the Spark test, this kind of test requires the sample metal to rub against the abrasive wheel, and by the spark it gives off, the metal expert will be able to identify the metal. This test is considered accurate, fast, convenient and economical.
