The knowledge

SPARK TESTING OF STEEL Spark testing is done for identifying wheater metal is ferrous or not.   A piece of metal to be tested is held against grinding wheel stone and an experienced person identify the spark being produced.  As the carbon content increases in steel the spark become more in length and colour become whiter.  Some of the sparks colours are given below that are produced by spark testing-    Wrought iron - straw in colour and become white at the end. Cast iron - red and become straw at the end. Low carbon steel -long shafts of white sprigs.