I just started watching this video, and have a long way to go to finish it, but it seems to have a lot of iron work in it, so here is the link: They seem to really have the metallurgy down well.
There used to be a few free foundry magazine subscriptions available to North America where they'd go into detail about the latest in cast iron metalurgy for heavy machinery diesel engines and the like. Quite a bit of it could be applied by the home foundry in the way of additives and recycling feedstock materials. As much as I like a paper copy (after filling the online subscription form with an Australian address) the website shows the latest edition of the magazine. https://www.moderncasting.com/ https://www.foundrymag.com/
I have not had time to study the foundry sections of the video closely yet, but I did see that they pulled plungers in the pour basins at 10:50. And the gating and passages look pretty convoluted, but not doubt they have it down to a science. And they reuse all their scrap, so there goes ironside's argument about not reusing iron scrap. .
The pouring basin plugs reminded me of the “mousetrap” device I made a while back. The magnesium dramatically added at the end of the melt for the crank converted the iron to modular iron. It was interesting to see the off-gassing post cast. Is it not standard foundry practice to recycle “returns” to the subsequent melt. I buy foundry returns as my primary feed stock since they are of known composition. Denis
This is not the first foundry I have seen that uses the returns. It seems to be quite common, but I have not researched it extensively. I think it a matter of quality control, and having a good mastery of metallurgy. That was my thought too. Good to see that some here are keeping up with the big boys. I was surprised to see it, but obviously it is critical to have solid engine castings with no entrained air in the melt. .
I just paused it to come back and comment on the sheaths they are using to protect their pyrometer probes. Did I hear that right, they're made of pressboard? Jeff
a lot of the larger foundries see pyrometer probes as consumables. One use and toss it. cheaper than losing a whole melt to a faulty recycled probe.
I use commercial pyrometer probes and can usually get 10 to 15 readings at least from one probe. In use it is pretty obvious if the probe has gone bad---it won't zero out and the reading is obviously way off. The tip is quite fragile, so you can't bump it or push it down through a layer of slag. The commercial foundry that casts 30+ tons of ferrous parts per week taught me how to use them. They also reuse them until they fail. The ones I use have a paper with a lightweight moldable refractory tip that is about 1.5 inches diameter. The actual thermocouple is visible in a very thin quartz tube at the very end of the probe. The thermocouple wires are barely visible to the naked eye---much finer than a human hair. What paper tube (similar in constreuction to a firework rocket) is not covered by refractory is wrapped in aluminum foil. The foil burns off pretty easily and I rewrap the tubes every few measurements. Denis
Anyone try a 6dollar stainless thermocouple? Hell, if I get a handful of dips in bronze I'd be good with that! I'm done dinking around with graphite gouging rods. I'd like to think I've gotten pretty damn good judging by eyeball. https://www.amazon.com/T-PRO-Thermo...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
Really good video. I actually watched it twice,(from start to finish). On the machining and fitting side, things were a little bit embellished. These engines are turning less than 1200 RPM, The accuracy is not super huge. But… This coincides with their life expectancy of 35 years. I did enjoy the metallurgy applied to the poor situation, and plug speed filler gates. Metal’s mixtures create different grin structures for sheer forces and Permissible forces. Very neat, thanks
It kind of chaps me that they always have to dumb down these videos for the masses. They talk about the power of the furnaces in terms of quantities of microwave ovens, as if nobody has ever heated anything with more than a microwave oven. Give me a break, just state the kW. At 6:00, interesting that they are looking for the sample to cool down at a certain rate, and then have the cooling rate reverse on a bit of a plateau. An exothermic chemical reaction going on in the melt? 6:52, nice tilting furnaces. I would build a tilting furnace, but the crucible costs would be excessive compared to just using a standard Morgan salamander super, and the furnace would be more complex. And it would force you to have a high temperature ladle, and so you would have to maintain crucibles and ladles. Looks like it is more efficient to run multiple small furnaces than one large furnace, and probably easier to keep control of things and handle material too with a smaller furnace. 7:00, interesting about the magnesium adding elasticity to the iron. No doubt you could learn a great deal about iron castings with destructive testing and some good spectral analysis. I guess every engine they produce is a test case, and I assume they have accurate records of the melt composition for every engine, and so you would over time find out which composition was brittle and prone to cracking, and which engine blocks did not crack. Edit: 8:40, the gates are quite small and thin compared to the runner. I am guessing there are numerous gates along the bottom of the casting. I would guess velocity is controlled using the small gates. Ceramic filters used to get rid of slag. And a coating added on the sand probably as much to assist in cleanup of the casting as it is to do with surface finish. 10:35; the guy is doing the "iron dance" (remember you heard it here first), where he gets some splatter from the misaligned pour on the left. Been there, done that. 11:33; looks like they are heating the mold from below with natural gas to control the cooling rate? Or is that combustible gasses escaping from the top of the mold? I guess the resin is burning off. 14:40; sprues shaped like plumbing gas traps, for the same reason that plumbers use them, to trap the gasses? Or perhaps it is a velocity control mechanism? 14:55; I am surprised they are not using a plasma arc device to cut off the sprues. 15:32; long continuous riser on the top of the casting? Actually, I think they rotated the casting upside down, and that is the runner at the bottom of the casting. Germans are very good at making iron castings, and making large high precision machined castings. There was a guy one of of the forums who worked at a place making I think the end supports for giant lathes. He said nobody could match what they did as far as time from beginning the design to having a finished casting (a matter of a few weeks), and precision/accuracy/quality. He said some could beat them on initial price, but the actual price of a casting depends on time to put it into production, how well it performs, how well it lasts, etc. Initial cost is just one small part of the overall cost equation. .
