The Intimate Sound of Molten Metal

We received a request last week to quote 4 U-shaped, 1800 lb capacity iron pour ladles. It has been almost 2 years now since we have had a request to quote any ladles. Up to this point we would make anywhere from 5 to 20 per year ranging in size from 150 lb to 35,000 lb capacity. Not all of these would be pouring ladles, we have also made tundish and duplex ladles for aluminum and iron foundries.

This recent request got me thinking about ladles again, and one of the most compelling thoughts was the sound of metal pouring. After graduating from Carlton University in 1990, my first job was with Wescast Industries. Wescast had recently purchased Galtaco in Brantford Ontario and I was in charge of bringing the melt and pouring departments into operation.

During the early production days when the plant started pouring, only one shift would run five days a week. To keep the day shift supplied with iron we kept the three five megawatt eighteen ton, line frequency coreless furnaces running throughout the night.

During the late afternoons and nights only two melt operators would be in the plant. It was common for me to work the night shifts to help out, and get the iron melted that was required for the day shift. I liked to turn off all the over head fans, that way all you could hear was the hum of the coreless furnace, sometimes the hum was more audible than others and a work order would be produced to check the shunts. Occasionally in the early days, a capacitor would self destruct with much the same sound as that of a cannon going off, during which time your heart stops beating in total fear for your life.

What I remember and enjoyed the most about these nights, when everything was turned off was the sound of the motel iron. When you toss a large piece of steel or cast into the molten metal and you hear the splash, more like a kuplunk, as it is not really a splash. Similarly when the furnace is poured into a ladle there is somewhat of a bubbling sound as the stream of iron hits the pool of iron in the ladle. If you have ever stood at the base of a water fall where water falls into a deep pool, it is that sound, but denser. That is the best way I can describe it. Experimenting with a launder system for a reason I no longer recall, the sound of the iron running down the launder was very similar to water running through a narrow rocky creek, but again I would describe it as denser. Noting the sound for the first time was surprising to me. After some thought it became obvious that there would be a noise associated with the pouring of iron, but the foundry is such a noisy environment you just don’t think about it. The furnaces being lined frequency they were always turned off when pouring, so even the noise of the furnace was gone.

Many years later Industrial Revolution Ltd. installed fume hoods into an aluminum smelting operation, through the night a similar situation happened, the dust collectors were off for some work we were doing, however the operation was still pouring Aluminum from the coreless furnaces to a reverb holding furnace. During the few times it had to be done you could hear the molten aluminum running through the launder system. Interestingly aluminum does not sound the same as iron when poured.

When I describe the sound of the aluminum, iron or water, to me, the viscosity is similar, I think of pouring warm molasses or cold maple syrup, the viscosity is much higher and the sound is totally different. Iron, aluminum and water have the same viscosity sound in my head however they do not sound the same as the higher viscosity fluids. To me the sound is denser. If I was a musician, I would probably describe it as a pitch / tone difference, but I am an engineer.

I regularly tell people that in order to push the limits of their individual discipline, it is necessary to become extremely intimate with your subject. I would use the sound of molten metal as an example of the intimacy level I believe is required to be good at your craft. I am not implying for anyone to go out and learn the sound of molten metal, however, if you are able to notice and learn something that would seam useless to most people and apply it to your discipline; this demonstrates having achieved a level of intimacy.