VIDEO HERE (28:20 minutes)
Created in 1959, "The Drama of Metal Forming" is an exceptional film that shows the forming of metal in a foundry. It was directed by Peter DeNormanville and produced by the famed editor Raymond Spottiswoode, the father of Hollywood director Roger Spottiswoode and distant relative of the Swindon Bakery's famous chef Angus Spottiswoode. Slabbing mills are rollers are shown, almost certainly located in the UK, and the many processes used to create finished parts such as railway car wheels (see the 17 minute mark), auto parts, gear blanks, wire, aluminum foil, and finished materials for the construction and oil industry.
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mold, and removing the mold material or casting after the metal has solidified as it cools. The most common metals processed are aluminium and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.
Melting is performed in a furnace. Virgin material, external scrap, internal scrap, and alloying elements are used to charge the furnace. Virgin material refers to commercially pure forms of the primary metal used to form a particular alloy. Alloying elements are either pure forms of an alloying element, like electrolytic nickel, or alloys of limited composition, such as ferroalloys or master alloys. External scrap is material from other forming processes such as punching, forging, or machining. Internal scrap consists of gates, risers, defective castings, and other extraneous metal oddments produced within the facility.
The process includes melting the charge, refining the melt, adjusting the melt chemistry and tapping into a transport vessel. Refining is done to remove deleterious gases and elements from the molten metal to avoid casting defects. Material is added during the melting process to bring the final chemistry within a specific range specified by industry and/or internal standards. Certain fluxes may be used to separate the metal from slag and/or dross and degassers are used to remove dissolved gas from metals that readily dissolve certain gasses. During the tap, final chemistry adjustments are made.
Several specialised furnaces are used to melt the metal. Furnaces are refractory lined vessels that contain the material to be melted and provide the energy to melt it. Modern furnace types include electric arc furnaces (EAF), induction furnaces, cupolas, reverberatory, and crucible furnaces. Furnace choice is dependent on the alloy system quantities produced. For ferrous materials EAFs, cupolas, and induction furnaces are commonly used. Reverberatory and crucible furnaces are common for producing aluminium, bronze, and brass castings.
Furnace design is a complex process, and the design can be optimized based on multiple factors. Furnaces in foundries can be any size, ranging from small ones used to melt precious metals to furnaces weighing several tons, designed to melt hundreds of pounds of scrap at one time. They are designed according to the type of metals that are to be melted. Furnaces must also be designed based on the fuel being used to produce the desired temperature. For low temperature melting point alloys, such as zinc or tin, melting furnaces may reach around 500° C. Electricity, propane, or natural gas are usually used to achieve these temperatures. For high melting point alloys such as steel or nickel based alloys, the furnace must be designed for temperatures over 1600° C. The fuel used to reach these high temperatures can be electricity (as employed in electric arc furnaces) or coke.
The majority of foundries specialize in a particular metal and have furnaces dedicated to these metals. For example, an iron foundry (for cast iron) may use a cupola, induction furnace, or EAF, while a steel foundry will use an EAF or induction furnace. Bronze or brass foundries use crucible furnaces or induction furnaces. Most aluminium foundries use either electric resistance or gas heated crucible furnaces or reverberatory furnaces.
It's actually 1959, and was well worth watching!
ReplyDeleteThanks, Ken!
Been involved with foundries for over 40 years. Love this stuff. Worked furnaces from 100# to 20 tons. Hard work but worthwhile.
ReplyDeleteIf you'd like to try your hand at this on a bit smaller scale, go here:[https://www.backyardmetalcasting.com/]
If you feel REALLY ambitious, go here:
[https://stephenchastain.com/store/index.php?main_page=product_info&cPath=1&products_id=3]
I melted steel from 100# to 10 tons, inductions. Did that for 35 years, making steel for remelt. We did iron, nickel, and cobalt base. The cobalt base was almost exclusively for medical implants.
DeleteA lot of what we did was for firearms, boat propellers, food service equipment, and anything that called for a special alloy.
We also had vacuum furnaces that melted nickel based alloys under hi vacuum, for aerospace applications, like jet engines, and NASA, like the space shuttle, etc.
After that, I worked running a couple of aluminum furnaces, one with plain aluminum and another with aluminum/magnesium. They were both fired with gas torches to keep them molten, plus their mass. Like WiscoDave, I loved the industry, and I hired into it at the age of 18 years, 3 months. I learned when the place was just a tiny job shop. We had a company that brought molds in on a truck, drove them onto the shop floor, we had melted the alloy and gotten it into spec. and poured the molds filled, they let them cool, and trucked them back to their plant to finish them. The parts were boat propellers.
When I left, the entire company of Mercury Marine was buying their alloy from us for their boat propellers and also for their impellers for their jet skis.
When things were really bad, in 2008 or so, we got a huge order from the government of Columbia, for alloys that are used for AK 47's. Things like 6150, 17-4, 410, 416, and a few others. Once, we got all of the coins from Mexico to melt down, while they were issuing new coinage. They sent representatives to watch us melt them, to ensure that they all went into the furnace. Of course, I think I have one or two here at home as an example.
We also melted down all the classrings from Jostens and Artcarved, Balfour, and some smaller unknown companies. We got NFL championship rings for commercial sale, 300 pin bowling rings, all for remelt. most of these didn't have stones, but perhaps 1/4 had stones, and were final polished. They were actually ready for sale, and were beautiful. Some companies had smashed the nice ones with a hammer, to keep people from selling them, but a lot of them were nice.
I did every job in the place, from running the furnace, to shipping,recieving, working in the lab, pouring with a 10 ton ladle, running a casting machine, and all of the other jobs that are involved.
I have a link that is one of the tough parts of working in a steel melt shop. It is not for the faint of heart. And not all of the reporting is correct, but enough of it is, that it will give you the idea of the more difficult parts of the job. Even worse, a similar thing happened to a friend, years later.
https://www.latimes.com/archives/la-xpm-1987-12-20-mn-29964-story.html
The clever thing about casting is allowing for the metal shrinkage, or contraction, as it cools. The pattern or former for preparing the casting sand mold has to be over-size.
ReplyDeletePre digital days the pattern maker used over scale rulers for determining dimensions.
Also note how dangerous working practises were back in those days.
One man is smoking a pipe.