How to tell the difference - Cast - Steel or Iron?

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Hi everyone.Is there a visual, mechanical or chemical test to tell the difference between cast steel and cast iron? Non/least-destructive. My understanding is that there are siginificant differences for the repair of one or the other.Thanks.
Reply:I tell from the sparks, and you need to weld cast with a nickel rod. It takes lots of pratice not to get pin holes in cast when welding. Go to your scrap yard and find some for pratice.Spark testing is a method of determining the general classification of ferrous materials. Normally it entails taking a piece of metal, usually scrap, and applying it to a grinding wheel in order to observe the sparks emitted. Wrought iron sparks flow out in straight lines. The tails of the sparks widen out near the end, similar to a leaf. Mild steel sparks are similar to wrought iron's, except they will have tiny forks and their lengths will vary more. The sparks will be white in color. Medium-carbon steel  This steel has more forking than mild steel and a wide variety of spark lengths, with more near the grinding wheel.High-carbon steel has a bushy spark pattern (lots of forking) that starts at the grinding wheel. The sparks are not so bright as the medium-carbon steel ones. Manganese steel has medium length sparks that fork twice before ending.  High-speed steel has a faint red spark that sparks at the tip.300-series stainless steel  These sparks are not so dense as the carbon steel sparks, do not fork, and are orange to straw in color.310-series stainless steel  These sparks are much shorter and thinner than the 300-series sparks. They are red to orange in color and do not fork.400-series sparks are similar to 300-series sparks, but are slightly longer and have forks at the ends of the sparks.  Cast iron has very short sparks that begin at the grinding wheel.Nickel and cobalt high-temperature alloys  These sparks are thin and very short, they are dark red in color, and do not fork.Hope this helps you.
Reply:Yes, actually it does. Thank you.That brings up a couple of more questions if I may.Is there any particular grit of wheel that works best?If it's a damaged part with no "pieces" to test. For this example, simply cracked?If cracked, using a hand held grinder on a "test" spot, such as the crack itself, it should produce the same results, given enough space to produce the spark trail, correct?Thanks again.
Reply:JR that is quite a list you have compiled. Is that something you know well enough to tell at a glance, or do you refer to some kind of cheat sheet? Titanium sparks are BRIGHT WHITE, pretty neat.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Originally Posted by millratYes, actually it does. Thank you.Is there any particular grit of wheel that works best?If it's a damaged part with no "pieces" to test. For this example, simply cracked?If cracked, using a hand held grinder on a "test" spot, such as the crack itself, it should produce the same results, given enough space to produce the spark trail, correct?Thanks again.
Reply:Originally Posted by tanglediverJR that is quite a list you have compiled. Is that something you know well enough to tell at a glance, or do you refer to some kind of cheat sheet? Titanium sparks are BRIGHT WHITE, pretty neat.
Reply:Thank you everyone for your responses.I'll need to scrounge some scrap and develop an eye for the tests. Then I will need to research the "correct" repair procedure for each type.The part in question was a "leg" from an old burned out patio type firepit. I didn't have anything to loose so I ground it and thought it to be steel. It's nothing more than a flower pot project now, nothing structural or any other potentially injurious application.Anyway, I TIG'd the broken ear with ER308L filler, Argon and 2%T tungsten. It may not have been the correct procedure, but it didn't fail when tightened. I was a little couriuos I guess to see if it would work. The weldment held when tightened against a rounded contour.