Latest iron melt.

[100model]

I have made a video of my latest iron pour and go into some detail about what metals in the iron group not to use. Steel can be mistakenly added to a iron melt and will raise the melting point depending on how much has been added. Ductile iron can be used but if you are a beginner it would be best to avoid it until you have some experience melting iron. Ductile iron uses powerful carbide stabilizers to turn the flakes of graphite into spheres so there is a chance that the iron will have chilled edges.

 

[GreenTwin]

Great video, very informative, and nice casting.

Notice luckygen does not use an offset pouring basin, but instead pours straight down the sprue.

If you only watch one iron casting channel on the internet, this is the one to watch.

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[100model]

Thanks for watching my video. I don't know why some people think that a offset pouring basin is needed?

 

[GreenTwin]

Some of the books on gating and risering use the offset basin, and in some cases it is shown in the Navy Foundry Manual.

So once it gets into print, and general use, then it is very difficult to convince anyone that you don't need it.

I saw a simulation video of a pour basin, and it was churning metal badly, and not preventing aspiration of air down the sprue very well.

The square basin at the base of the sprue is also a big no-no, and it churns the metal very badly too.

I do put my gates on top of the runner, and use a spin trap at the end of the runner.
I don't step my runners, but just use a linear runner, and I don't have fill problems.

As Bob Puhakka has pointed out many times, pretty much every method that is commonly used in most commercial foundries is a bad idea.

As I recall, Bob said that the cross sectional area at the bottom of the spure should match the cross sectional area of the runner, and the sprue should have a very smooth transition into the runner, with no sharp corners.

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[DaleW]

There are a lot of times when an offset pouring basin is required, particularly if you don't use a filter. The concept of them is to act as a slag trap and you need to keep them at least 3/4 full when pouring as this limits the air down the sprue. There are many calculations that go into determining the design of your runner and gating system. For the home hobbyist you don't really need to worry about 90% of them. The best way to think of your runner and gating is to think of them like a river, smooth with no sharp edges. For cast iron I always use runner on top of gating to help feed the casting or I direct pour. The picture on that book is actually what not to do. There are a lot of older books out there on the subject and they all have there place depending on what your doing, size of the casting, what will the mould be made of (greensand, chemset etc), how will it be poured, what metal spec will be used. Apart from brasses and bronzes, cast iron and sg iron are my favorites.

 

[100model]

Dale, do you pour S.G. iron at home?

 

[GreenTwin]

There are many methods used for risering/gating, and opinions vary greatly on how to best do it.

I have seen a variety of methods work, and so I think it is a matter of finding a method that works for you, and using that method to get consistent results.

In a very general way, I would say avoid turbulence as much as possible, avoid air aspiration down the spure, keep the velocity of the metal as low as possible while still achieving a complete mold fill, try to arrange things so the metal stream is self-skimming, and pay attention to shrinkage and things that cause shrinkage defects.

The proof of anyone's method is in the pudding as they say.

Pour some gray iron parts, section them to look at the inside, and then see how well the thin parts machine.

There should not be any inclusions, air bubbles, slag, hot tears, pinholes, etc. in the metal, and all parts should machine easily without tempering, even the thin parts. Can you pour iron and get consistent results every time? That is the challenge.

I am a big proponent of casting a near net (I think that is the correct foundry term) part, ie: the casting is only slightly larger than the machined part, and the distortion is amost zero, ie: round parts come out of the mold round, not oblong.

Bound sand gives a lot more accuracy than the traditional greensand method.

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[DaleW]

Dale, do you pour S.G. iron at home?

I used to, but not since I moved house. The neighbors aren't as tolerant here, lol. I was lucky I new what the scrap was I was using so could adjust accordingly and I would do a wedge test to check. I've seen some spectacular home failures too, with crucibles not designed for the sudden temp increase.