My position at Alcoa

Stepping away again from my normal blogs about fitness or travel or social networking. I wanted to share what I do at Alcoa. Alcoa is one of the largest, if not the largest company in the world that produces and manufactures aluminum, and aluminum parts. My position(described below) ispretty dangerous. I have been burned by molten metal (nothing too extreme thank goodness, and hopefully it will never happen.) I have been involved in explosions, and it doesnt take much. Moisture on the iron bars, even though we may not see it can still be there and THAT causes a big one. So imagine a significant amount of moisture, like the moisture from the human body. The flashpoint, coupled with the coolant (that big enough explosion would melt the coolant tubes and cause an even bigger explosion) would go to 3000° celsius in seconds, and we always have two furnaces operating. So half my section (the building) would be gone. Been with Alcoa six years. Time to move on and do something safer, like walk through my old neighborhood with $1000 sticking out of my back pocket!

JOB TITLE

FURNACE OPERATOR

JOB INDUSTRIES

FOUNDRY; STEEL & REL.

JOB DESCRIPTION (DUTIES, RESPONSABILITIES AND TASKS)

- May be designated according to type of furnace operated as Electric-Arc-Furnace Operator (foundry; smelt. & refin.; steel & rel.); Furnace Operator, Oil Or Gas (foundry); Induction-Furnace Operator (foundry); Tilting-Furnace Operator, Oil Or Gas (foundry). . - May transport crucible or ladle to pouring station and pour metal into molds. - Positions new electrodes over worn electrodes in electric-arc furnace, using overhead crane, and screws electrodes together, using chain wrench. - Records data from each melt on form. - Removes test sample of molten metal from crucible, using hand ladle, and pours it into mold. - Removes crucible containing molten metal from furnace, using hoist, moves levers to tilt crucible or open crucible door, or breaks clay plug to pour metal into ladle for transportation to molds. - Skims off slag, using strainer. - Sprinkles fluxing agent over surface of molten metal to bring impurities to surface, forming layer of slag. - Observes color of metal and instruments, such as voltmeter, ammeter, wattmeter, and pyrometer, and adjusts controls to maintain specified temperature. - Turns valves to regulate injection of fuel and air into furnace, or moves controls to regulate flow of electricity and water coolant through electrodes to heat furnace to specified temperature. - Loads molten metal into furnace, using transfer ladle. - Weighs out specified amounts of metal ingots and scrap metal, and charges metal into furnace by hand, using hoist, or by directing crane operator to charge furnace. - Controls gas, oil, coal, electric-arc, or electric induction furnace to melt metal prior to casting.

THE WARNINGS

Induction Furnace Explosions (Video Link)

Wet Charged Material

• A wet charge is any piece of scrap metal that contains moisture. Water or moisture present in scrap metal will instantly be converted to steam upon contact with molten metal. Moisture molecules may expand up to 1,600 times in a single instant. The violence of this reaction causes an explosion capable of launching large amounts of molten metal into the air. Damage to the furnace can occur, increasing the likelihood of a leak or secondary explosion. Induction furnaces are cooled by coils of water that wrap around the crucible in which the metal is melted. This increases the risk associated with adding wet metal to the furnace, as an explosion may rupture those cooling lines and cause the coolant to leak into the furnace. The coolant hitting the molten metal will create additional explosions.

Sealed Containers

• Many foundries melt scrap metal. This process often involves melting metal products back down for repurposing of the raw metal. Air and gases expand as they are heated. Adding a sealed-off, closed container into a furnace will cause the air or gas inside the container to expand very rapidly. Should the pressure inside the sealed container breach the container walls, an explosion will occur. Such an explosion may cause molten metal to be thrown from the furnace, landing on operators or sensitive equipment.

Bridging

• When metal being added to a furnace fails to make contact with the molten metal already inside the furnace, it is called bridging. Metal being added, called the "charge," is significantly cooler than the metal that is already melted. Adding cooler metal helps regulate the temperature of the molten material inside the furnace.

  Bridging occurs when a crust of slag forms across the top of the molten metal. This layer contains impurities and air or vapors. If the charge fails to penetrate this layer, the slag will insulate the molten metal and cause it to overheat. The charge will remain separate from the molten metal and the molten material will sit in the crucible and bake. Eventually the molten metal trapped in the bottom of the crucible will become hot enough to eat through the crucible and furnace lining and cause a fire underneath the furnace.The fire may destroy the hydraulic controls of the furnace, electrical controls and colling lines. If the molten metal contacts the coolant, an explosion will occur.

(After seeing the video above you can see why I am trying to get out of here, and be my own boss!)