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| Casting iron using Thermite instead of a furnace |
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| Rob.Wilson:
Hi Brian I suppose its possible ,you would end up with a steel casting ,not cast iron . Had a quick look through my foundry books and the only reference to the use of Thermite in a foundry was to raise the temperature of a ladle of molten steel to make it more fluid for casting thin sections .This was done by plunging a canister of Thermite into the molten steel . Rob |
| Pete.:
--- Quote from: spuddevans on January 26, 2013, 03:01:48 PM ---Somewhere in the back of my mind ( a dark and dangerous place, I don't like going there :lol: ) I seem to remember that the railways used to use such a mix to weld the rails together. Also I know that heavy duty copper earthing points are welded using the same method. Tim --- End quote --- They still use thermite for welding rail over here. |
| NormanV:
I produced a thermite reaction and was suprised to find that the resulting lump of metal was not magnetic. Can anybody tell me why? |
| Lew_Merrick_PE:
Tim & Pete -- And thermit is still used in rail welding here in the U.S. It is losing ground to capacitive-discharge welding using super-capacitors, but it is still in use. Norman -- Magnetic materials become non-magnetic when structural orientations change at temperatures higher than the Curie point. In theory (and I am unaware of anybody turning this into practice) you could create a non-magnetic version of otherwise magnetic alloys by a near-instantaneous cooling from a thorough soak above Curie point temperatures. This was one of the industrialization of space experiments (using the solar forge) back in SkyLab days. I was working on analyzing data from other experiments, but it was my understanding that this particular experiment failed. Brian is correct in terms of military usages of thermit. It is often used as an igniter charge in incendiary devices, but the primary distribution of fire is a different fuel mixture because of the way it concentrates its exothermic reaction. |
| raynerd:
Norman, when we carry out the thermite the vast majority of the product is not magnetic despite what looks to be some nice balls of iron (we do it over water so it forms balls). Our understanding is that our mix is not perfect and consequently the iron formed is contaminated with so much iron oxide, aluminium powder and various unreacted ignition materials that you can`t detect the magnatism from the produced steel. I could be miles away from the truth, but it seems very possible. It also rings true since the balls crumble easily, so they are clearly not pure iron - that said, some lumps are magnetic so it is working to a degree....and besides, it looks good! I`d love to see a video of them actually using the thermite reaction practically. We have to teach that it is used to "repair railways lines" but have no video showing it and in all honesty, no proof that this actually is done other than me being told to say so! good luck and stay safe.... Chris |
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