Cast iron that rings?

Aha. Manganese steel. Yes, it has some strange properties, but I don't know much about its applications.

There was some use of it for race-car space frames, in the UK and around 1960. My recollection is that they went back to mild steel, and then picked up on the material we use for that in the US -- chrome-moly, 4130.

These could be used as is to make small tools, flats, angles, etc. by machining close to shape and then hand scraping. For larger projects, then could be melted and poured to make bigger straight edges and angles.

I have a white iron straightedge and a set of white iron squares that I scraped in.

Jon

I'll bet that knocked the hell out of your scraper blades.

White cast iron will tear up almost any tools. Seco and Sandvik have developed special tools for cutting it, but they require a lot of horsepower and spindle speed.

Re-casting it is problematic. Unless it's a high-alloy iron (probably not, for digger blades), it can't be chilled fast enough to produce much white iron on the surface. When they sand-cast it, they add a lot of chromium to reduce the required hardening rate. That's expensive and typically reserved for fancy things, like slurry impellers.

Once you melt it and pour it, it's not white iron any more, unless you heat treat it properly.

Ed seems to know more about this than I do.

Well, I used homemade scraper blades made from large carbide indexable inserts that were pretty cheap. They worked very well. I DID have to sharpen them fairly frequently. This straightedge and square may not be exactly white iron, maybe closer to grey iron. The angle is unknown, the straightedge WAS described to me as white iron. Yes, they are pretty darn hard, and took a lot of elbow grease to scrape.

Jon