Picked up some 75% ferrosilicon

I was in the neighbourhood of an iron foundry yesterday and stopped in for a visit. The staff were really helpful and I was able to buy 8 kilos of 75% ferrosilicon. They mentioned they aim for less than 2.5% content in "as cast" grey iron. Unfortunately the foundry does not give any tours. It doesn't hurt to knock on some doors and ask nicely, they went out of their way to help me.

 

I used to live close to an alloy manufacturer. I never did stop to see if I could buy some. I do still have a bunch of alloys I bought at an auction.

 

I have been following melterskelter's extensive experimentation with ferrosilicon, and lucky for me he has it pretty much figured out (thanks much for that info melter, we owe you !).
For my last melt, I think I used 2.5 oz of ferro for about 19 lbs of iron, and I had very little shrinkage, and even the thin parts of the castings were very machinable.
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The key to FeSi I have read and confirmed through early mistakes is add it at the very end of the melt. I skim the crucible as instructed and then add about 5 oz to 50 pounds stirring it vigorously for a few seconds with a graphite rod. Then I pour usually within 2 minutes (and not more than 4). Early on, I added the FeSi to the melt 10 or 15 mins prior to pouring and it did not have the desired effect. Subsequent reading discussed the proper time sequence. Prior to figuring out the timing issue I added fairly large amounts of FeSi to no avail with respect to hardness and perhaps fluidity.

It goes into solution very easily and causes very bright light emission for a few seconds---pretty, really.

Denis

 

Thanks for the comments regarding correct dosage, that advice is priceless when getting started. Apparently it deoxidizes the melt as well as aiding formation of graphite, I guess that will improve fluidity. Will I need to crush the ferrosilicon to a sand-like consistency for the relatively small melts?.

 

No crushing needed. It melts fast. I use FeSi of about the same granularity. I think that it is melted in the few seconds I stir it.

Denis

 

FE does appear to help with fluidity.
It is a noticeable effect visually, but I can't define it scientifically.

Edit:
I always take great care in order not to damage my graphite stirring rod.
So for my last melt, I carefully pickup up the stirring rod, let it slip out of my hand, and sheared off the graphite from the holder.
So much for the graphite rod stir.

I picked up a thin steel rod that I keep on hand for probing the melt (which I seldom do these days), and used that to stir with. Worked fine.

Perhaps I will try a larger diameter graphite rod.
I think I am using a 1/2" diameter right now.
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Here is an article (there are many) on the effect of FeSi on iron.

http://foundrygate.com/upload/artig...on melts poured at different temperatures.pdf

I have used the same 1/2" graphite rod for just a little over a year. It has gradually become tapered as a little graphite must be melted off it with each use. I am sure now that I have said that, it will break next time. I do have a backup. It works better for me than steel which rapidly melts in the iron.

http://forums.thehomefoundry.org/index.php?threads/making-a-graphite-stirring-rod.456/

Denis

 

That article is a good read, Denis. I see that they mention inoculating with silicon carbide lasts for hours compared to ferrosilicon. I'll be using a steel rod stirrer to begin with until I can get some suitable graphite rods.

 

Yes, graphite is not really necessary. But, the nice thing is a lot of industry uses it, so, it is pretty widely available. Here in consumer paradise (USA) I got some on eBay for cheap. Like this: https://www.ebay.com/itm/Carbon-Sti...723106?hash=item28517b3de2:g:xhkAAOSwxPNb0qfI

Denis

 

I'll have to try the local welding shops and see what's available. McMaster won't sell outside USA and Canada these days but there'll be something comparable. The Salamander Super showed up today so I'll get busy fabricating a gripper/heat shield to suit and then shorten the plinth by an inch with a diamond saw to get more lid clearance. After that I'm ready for another attempt at iron.

 

I guess I am confused?

Why do you think what I linked is not graphite? That’s the description I read.

Here is Mcmaster’s 17 dollar 1/2 x 6” graphite rod: https://www.mcmaster.com/graphite-rods

Your link takes me to stick electrodes for welding:


Denis

 

Kelly,

I am sorry, but you linked flux-coated welding rod clear as day. I would not want to use that to stir my iron.

I have no doubt that MCM describing graphite rod as graphite is an accurate description as they are the most reliable online vendor of which I am aware. Just like the graphite rod I bought from eBay is, indeed, graphite I can tell you based on my experience.

I would recommend eBay suppliers with lots of excellent feedback as an economical source of good quality graphite.

Denis

 

Yes, indeed. I said I was confused! And I was. (I am just coming out from under a energy-zapping cold) I actually did scroll down a couple pages on the original link, but gave up and did not scroll all the way to the bottom. I think it is a safe bet those uncoated gouging rods would be the ticket. You would expect them to be pretty rugged considering their intended use. As you say, wonderfully cheap. And for our Australian friends, there would be a decent chance of getting them at a well-stocked welding supply----bonus.

Good find, Kelly.

Denis