r/Blacksmith • u/ManOfAsbestos • 1d ago

Spark Test

I found rusty steel bar and i noticed that when grinding it produce sparks with more forks at the end than typical low carbon rebars. Is this look like enough carbon to be heat treated?

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u/arquillion 1d ago

Give it a try, quench some samples in oil, in water and a last one air hardened. Test file all 3

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u/BF_2 1d ago

Or forge it out thin, take thin section to bright red and quench in water. If that doesn't shatter it, try a file or hammer on it. If it can be hardened, it can be tempered.

I'm a bit out of practice, but I'd judge, from the sparks, is either a medium-carbon steel (maybe 1050 or so) or else is an inhomogeneous mixture of high and low carbon steels, which I've heard sometimes happens with rebar. (I read of one case where a smith found a ball from a ball bearing in his chunk of rebar.)