Casting Ductile Iron

Discussion in 'General foundry chat' started by PatJ, Oct 11, 2019.

  1. PatJ

    PatJ Silver Banner Member

    I have been pondering making ductile iron for a while, and Jammer gave me some additive to try (ferro-mag I think).

    As I read about magnesium being part of the additive, I of course think of the safety aspects of molten iron mixing with anything that has magnesium in it.

    So my plan is to figure out ductile iron next spring, so I can make crankshafts for engines.

    Luckily it would seem that others are paving the way for me, ie: the local Metal Museum folks and the artists that come from all over when they do their iron pours.
    Here is a video that castirongypsy posted today of them making ductile iron at one of their iron events.
    I don't remember this at this year's FIRE, so perhaps I missed it, or it could have been at another event, and I was not aware that they were casting ductile iron.

    I think adding ferro-mag will require taking safety to a much higher level, but it would be very exciting to be able to master this material and method.

    I think the greatest danger would be having a reaction that ejected iron and ferro-mag out of the crucible and onto your pants, jacket, headgear, feet, etc., because it may stick and then burn its way through just about anything.

    I think a metal shield (like 48"x48") may be a good idea to stand behind until the reaction is complete.
    Luckily they did not panic in the video, which could have turned a difficult situation into a dangerous one.

    Last edited: Oct 11, 2019
  2. Jason

    Jason Gold Banner Member

    Yeah, that would have caused me to leak a little down my leg.:oops:
  3. Melterskelter

    Melterskelter Silver

    Ya know, I think if I were going to add magnesium to grey iron I would rig up a tippable chute or scoop that had a 20 foot or so trip wire on it and a damn relaible trigger. Load the scoop. Walk well away. Hit the electronic or mechanical trigger and watch all the fun from a safe distance. I would also be taking very definite precautions in storing and transporting the magnesium.

    Did the Metal Museum folks test the resulting iron to confirm that it was indeed nodular? Not doubting that it was nodular and not doubting they did test it. But it is always nice to see confirmation of the idea you are new to using. I am a little surprised that the MM folks did not anticipate the reaction of a sizable amount of MAGNESIUM added to molten iron! Good that they had on the PPG that they were wearing.


    Added: I think the guy with the thermometer called out 2650 as the temp of the melt. Maybe someone with better ears than mine can correct me on that if needed. I imagine the mag added a few degrees to the melt!
    Last edited: Oct 11, 2019
  4. Melterskelter

    Melterskelter Silver

    Here is an example of how it is done in industry:

    Most of us are not likely to setup an enclosure with exhaust fan.

  5. PatJ

    PatJ Silver Banner Member

    I am assuming that video was from the latest FIRE event, but I am not sure.
    I was busy all day during their iron pour trying to put my shattered hot face back together, and so I only occasionally walked over to watch them.

    As long as there was not an explosion or large splatter, then it is just a matter of protecting the eyes, since a single shade is not nearly enough for that sort of light emission, and perhaps not standing too close to it from a radiant heat standpoint.

    But a simple sheet metal shield would easily handle the problem I would think, and have a hole in the center of the shield for the stirring stick to go through.
    Obviously if it were a big problem, then several of the folks standing right next to it would have been injured.

    I will probably beef up my protection with a cover over the back of the neck, and a cover over the front of the neck too.

    At any rate, I don't know the story on the ferro-mag addition (I assume it was ferro-mag), but I will find out and post it here.

    They have a major iron foundry in Alabama that is one of their sponsors, and so they basically have an infinite fountain of knowledge.

    Last edited: Oct 11, 2019
  6. PatJ

    PatJ Silver Banner Member

    Yes, I would say you could melt a crucible if you were not careful.
    I am not sure what the ladles that they use are rated, but they are some sort of lightweight material, and they seem to hold up well to iron temperatures.
    The ladles are not exposed to oil burner temperatures, and so I am sure that helps them last longer.

    If possible, it would probably be best to introduce the ferromag into the center of the melt, away from the sides of the crucible.
    Plunging would probably be a bad idea, since that may cause an explosion.
    Last edited: Oct 11, 2019
  7. PatJ

    PatJ Silver Banner Member

    This may be a situation where a self-darkening welding shield would come in handy.
    With a single #10 shield, this much light basically prevents you from seeing, as you can see from the guy trying to walk forward on the left.

    When I do iron pours, I wear a #10 face shield, and then wear a #10 set of glasses under than, and that is without any ferro-mag added.

    One would really have to err on the side of caution when dealing with ferromag.

    I think I would attach an 8 foot extension rod on the end of my pouring cart, and use a small cup on the end of the rod to add the ferro-mag.
    That would put me over 10 feet away from the crucible, which is probably as close as is safe to be.

    And I would use a 48"x48" shield about 36" back from the end of the rod, or perhaps at the front of the pouring cart.
    One would really need to plan on an explosion, since that would be possible, and have enough safety gear to safely deflect that.

  8. Jammer

    Jammer Silver Banner Member

    I thought more about a crucible cover with a some type of drop mechanism to drop the NiMg3. #2 is the cover with a small shield to deflect the reaction away. I thought there had to be a push plunger but the NiMg3 is heavier than Iron so it sinks to the bottom. You have to pour within 10 minutes or so or the reaction will stop and it will go back to flake graphite and lose the ductility.
    crucible.png crucible 2.png
    Melterskelter and Tobho Mott like this.
  9. Melterskelter

    Melterskelter Silver

    Maybe the handle on the shield shown above could actually be a steeply angle 1.5" or so tube down which you could pour the ferromag. (Personally, I still like the idea of being well back and using a triggered tip when the addition is made, but a simple cover as shown would be fairly simple to make and should provide protection too.)

    And for sure, whatever scheme you use for adding magnesium, you would want to be making the addition outside the furnace with its lid closed. There is no telling what all that flaming magnesium and whatever else that blows back will do to your furnace lining.


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