Simple Field Tests to Distinguish Different Irons

Simple Field Tests to Distinguish Different Irons

              cast iron can be readily distinguished from wrought iron by its crystalline structure, by structure its want to ductility and its brittleness. If a piece of cast iron is struck with a hammer it breaks clean without bending and the fractured surface presents large grains of whitish gray and dark colour with black spots interspersed, while wrought iron when struck bends and then breaks and the broken surface presents an uneven thick fibrous appearance .

Heat and bending Test:

            cast iron cannot be bent when cold while wrought iron can be bent very easily and steel can be bent with some difficulty. cast iron breaks very quickly when heated while steel can be bent easily when hot.

Sound:

              Steel when struck gives a treble musical or sharp metallic ring like that of bell metal, wrought iron a note of a low pitch, while cast iron when struck gives a hollow sound.

fracture:

               A fracture in steel is granular in wrought iron fibrous and in cast iron crystalline in appearance.

Acid Test:

                Apply a drop of nitric acid on the iron to be tested and let it remain for a moment, and then rinse with water. There will be no perceptible stain  on wrought iron; a dark grey strain on steel ; and a black or brownish strain on cast iron, which is due to the presence of carbon.

The ASTM A262 Chart for Selection of Testing Practices