Tips about what metals to use in a iron melt.

Discussion in 'Sand Casting' started by Ironsides, Oct 10, 2022.

  1. Billy Elmore

    Billy Elmore Silver

    First...the videos are awful compared to the program browser which is how you view them inside the program. On the browser you have full control to see everything and change how everything looks. I only use the videos to share with people and have to be really specific as to what I am trying to show them. I can choose the temp before running the sim and 2650 is about where we need to pour these thin wall castings and as you can see in the vid it was really cold at the top of the casting but still liquid so we would have tried it like that if we went that route. Not a typical gating system for us. the velocity at the ingate is much higher to prevent misrun with the CGI viscosity. It also loses head pressure as the casting fills, so you have to allow for that. The sims do not really have a set up for doing these types of processes with a delay between poured sections. I have to manipulate the program to pour a certain weight with a choke set in place that will not allow metal to pass through it until the weight is reached. I can also do a percentage of the mold filled but weight works best. So the time delay is not quite accurate but we do not need the basin to be full for a full three seconds...as long as the alloy has been saturated for at least three seconds you will be good. So if you take three seconds to fill the basin you can dump it instantly and be good. The design/shape of the pouring basin was new to the process and has not been tried in production but based on my sims is a huge improvement to the old style that we actually used. It is yet to be seen how well the reaction chamber speeds up the melting of the alloy...but it looks like it should mix it up well and gets the metal into the basin much faster and with much less inertia which would carry metal over the top of the basin if it was not controlled. The program does an excellent job of predicting shrinkage and other defects but was created mainly for shrinkage. We will see shrinkage at the 2650 temps around the handles and other thicker places which is why we have not went back to this process and have instead went went with higher strength grey iron and added guards around the castings to protect them against breakage through our process. I recently ran a sim of a large pipe adapter for Charlotte Pipe to compare to their program...Magmasoft. Our...NovaCast...found the shrink they were getting but they could not find it with Magmasoft. They are now looking at switching to NovaCast. I should get a seller's fee.LOL
     
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  2. Billy Elmore

    Billy Elmore Silver

    Starting with ductile is a big plus as the sulfur will be low enough that it will not eat the NiMg3. You can add quite a bit of the stuff without hurting anything (only a little flare) so on the first attempt... alloy heavy and make adjustments based off of those results.
     
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  3. Tobho Mott

    Tobho Mott Gold Banner Member

    In this screenshot from 2:40 in the video you can see a powder being poured into the stream of iron coming out of the ladle. I guess they are making ductile castings here? Just before this scene you can see a guy beside the ladle release the can of powder so that it tilts with the ladle and allows the powder to sprinkle out this way. Thought it was interesting and (perhaps) DIY-adaptable.

    Jeff



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  4. Ironsides

    Ironsides Silver

    It would be adding ferrosilicon at the last moment so the fading effect will happen.
     
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  5. Billy Elmore

    Billy Elmore Silver

    Just inoculant..if it were NiMg3 there would be lots of flaring and they usually try to get it under the melt...hence the reaction chamber in the in mold process.
     
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  6. Melterskelter

    Melterskelter Gold Banner Member

    And I think Billy is referring to FeSi as "inoculant."

    Denis
     
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  7. Billy Elmore

    Billy Elmore Silver

    Yes...sorry for any confusion. It was mpost likely FeSi with whatever trace amounts of only god knows what to make one suppliers better than the others.LOL If it had been a ductile treatment it would have been just a little brighter.
     
  8. metallab

    metallab Silver

    Well, NiMg3 is probably an alloy of Nickel and only 3% Magnesium, so that does not ignite when thrown into the iron bath.
    But for amateurs ? I tried adding Mg lathings into cast iron which indeed flared up, but to make ductile iron this is not enough. A heat treatment of several hours or even days with controlled temperature is required. This is only possible in commercial foundries, unless you are willing to pay several grand for such a heat treatment furnace.

    I have read that adding 20% Ni and a few % Cr makes it harder, but I don't know about ductility about such 'stainless cast iron'.
     

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