Where Is Magnesium Used Anymore??

[rmoore]

A member of the HazMat team for a large city here in Texas wrote with a question that I need help answering.

"Ron, to your knowledge does any of the car makers still use magnesium in the engine blocks or frames? I know the older VW's did but don't know if the newer ones do.

Reason asking, we had a magnesium fire several weeks ago here in Dallas at a scrap metal yard. Only 220,000 pounds of magnesium on fire. Firemen couldn't understand why it would not go out with all the water they were dumping on it.

We as hazmat, told them to stop putting water on it and it would quit exploding. It worked.

Trying to work up a school on magnesium fire and was curious about enging blocks or any other engine parts on newer cars. Thanks"

Any Message Forum readers have any further information?????

[JorgHeck]

Magnesium is still one of the materials used in modern cars, especially because it is lighter than steel. I know that its used in some parts of the engine and also as a part of doors etc. Because I'm from germany I could not give you special examples where it is used in US-cars.

[FYRHWK1]

Many cars use it for things such as transmission cases, ford explorers and everything that uses that same transmission as well. I'm not positive, but I believe the cases used ont he GM 6 speed manuals are as well. There was an old volvo that had the entire engine block made of magnesium if I remember right too. It's not super common but it's being used more and more often, our rescue carries a class D extinguisher for magnesium just in case that happens.

[SPFDRum]

If memory serves, Chevy CK pick ups have/had a magnesium bar along the firewall, under the dash for strength.

[FYRHWK1]

Question about magnesium, I know it burns extremely hot, but what's the flashpoint of the metal? I was under the impression it was insanely high, almost high enough you wouldn't really reach it with a car fire, at least not a normal one.

[NeilMcD]

Originally posted by FYRHWK1
what's the flashpoint of the metal?

The flashpoint for Magnesium is 1173 degrees F. I don't believe the car fire temperatures get that high since most of them occur in open areas. I do believe the only time you need to consider the magnesium flashpoint is when you have an overabundance of fuel (eg. car crashes into a gasoline tanker or something like that).

Then again, I've heard the same thing about the older VW bugs.. they were deathtraps because they used so much magneisum in the engine. THe only thing I can think of is that they used a magneisum alloy with a metal that has a lower flashpoint which in turn, ignited the magnesium?

[hotjob]

Your right it does have a high flashpoint but if you get burning tires on a car, is that not enough heat to ignite the magnesium. The specific fire we had was at a scrap metal yard. The magensium was ignited by wooden pallets which were on fire. I believe the magnesium has some alloy in it because it burned with a yellow and bright white flame instead of just a bright white flame. It did make some pretty inpressive pictures of a nice mushroom cloud explosion.

[NB87JW]

Ron,

To answer your question about magnesium being used in Vehicles now adays. YES it is used quite a bit still in both European and US cars. I have not seen it much in the Asian cars but it may be there as well. We won't find in as large of quanities as we use to on cars/truck but scattered throughout the vehicle in smaller sizes. Refer to this link ( http://www.magnesium.com/w3/uses/ ) to find out more uses not only in the automotive industry but in several other fields.

Be safe Bro's
Fraternally, Jordan

[FYRHWK1]

Originally posted by NeilMcD


The flashpoint for Magnesium is 1173 degrees F. I don't believe the car fire temperatures get that high since most of them occur in open areas. I do believe the only time you need to consider the magnesium flashpoint is when you have an overabundance of fuel (eg. car crashes into a gasoline tanker or something like that).

Then again, I've heard the same thing about the older VW bugs.. they were deathtraps because they used so much magneisum in the engine. THe only thing I can think of is that they used a magneisum alloy with a metal that has a lower flashpoint which in turn, ignited the magnesium?

http://msds.pdc.cornell.edu/msds/msd...0.htm#Section5

This gives no flashpoint for zinc (I couldn't find it anywhere actually) however an autoignition temp of 860* F. Zinc is from my searches, a pretty common element in magnesium alloys, so it could be the zinc igniting the magnesium. Seems my terminology is wrong though, flashpoint refers to the vapors of a liquid, though I suppose the gasses put out by heating magnesium should be the same as if it were liquid vapor. Autoignition seems to be the point at which heat will ignite it without an open flame acting on it, I wonder if it's any different with open flame on it or if it jsut reaches that ignition temperature faster.

[RyanEMVFD]

company vehicles used for plumbing can carry magnesium rods and can carry oxy acetlene tanks which can make these vehicles pretty dangerous.

[EFD840]

We also encountered what I assume was magnesium in a storage shed fire. The source appeared to be a couple of chain saw engines. It scared the stew out of me when I hit it with a 1 3/4 and got a minature reenactment of a war movie scene!

[martinm]

BMW still use magnesium components in their vehicles engines. As with all things, there is'nt much to tell you about it until you get water on the engine compartment during a fire. We have a "safety flash" about this at work, will see if I can dig out the rest of the info.

[explr985]

I have never heard of Class D fires until recently, but I know there are Class D extinghushers, but can you fight Magnesium fires with a CO2 or ABC extinghushers?

[ARFF26]

Magnesium is used for wheels on many aircraft. Hard stops causing hot brakes are sufficient to cause ignition. Knock down flames with dry chem and cool with water, it will pop and sparkle but without cooling you'll get re-ignition.

[jonesy0924]

Well I know my Oakley Sunglasses are made of magnesium...Also I believe VW uses it as well...First hand expierence on that one..

[F52Westside]

Apparently after reading another post, the new '04 F-150s have magnesium in the front ends.

F-150s and Magnesium

[MetalMedic]

It just so happened that this topic came up in a discussion at our county fire school last weekend. A firefighter from a neighboring department is a body man at a local GM dealership.. He informed me that the radiator mounts in some new GM vehicles are made from magnesium for weight reduction.

[Dalmatian90]

Um, do metals have a flashpoint? Ignition temp, sure...but a flashpoint?


http://www.immnet.com/articles?article=1418

IMM asked Steve Erickson of Noranda Magnesium to give us a better picture of this metal's nature. (Noranda Magnesium is a new division of the major mining and mineral company.) Erickson is a marketing executive involved with both technical service and application development who spent 33 years with Dow Magnesium. In the following, Erickson addresses three of the myths surrounding this material.

Myth:All magnesium ignites easily and, once ignited, is difficult to extinguish.

Fact:It is true that magnesium (Mg) can be ignited. Once ignited, the fire can be sustained in air under the right conditions. This is about the only principle ever demonstrated by the chemistry professor. (Erickson's high school teacher even put the strip into a bottle of oxygen to enhance burning.)
When a strip of Mg is very thin, you can supply enough heat to ignite it with the flame from a Bunsen burner. Even then, to get it to burn, you have to tip the strip downward to heat the area above it. That puts more of the heat of the flame into the metal.

For most alloys of Mg, the ignition temperature is 850F. The metal has good conductivity, so it takes a high energy source to heat it up and get a local spot up to the ignition temperature. If the cross section of the piece is large enough, the amount of heat generated from the burning will be conducted away from the ignition point, extinguishing the flame.

When a bigger piece of Mg, such as a TXM or diecast part, is put in a high-temperature environment (an oven or a burning car), it's possible to get it up to a temperature where it will ignite and burn. Even then, it is usually the last thing to burn. Investigators have looked at old VW Beetles, which had about 60 lb of Mg in them. In a car fire, the entire car is consumed before the Mg will ignite.

One of the interesting facts about Mg fires is that even though a bright white light is emitted during burning due to the high flame temperature (hotter than 5000F), it only gives off half the amount of heat compared to carbon-based fuels-10,000 vs. 20,000 btu/lb.

It is also true that finely divided pieces of material (i.e., powder and ribbon) burn readily. This also occurs with grain in silos, which are prone to dust explosions. Light materials that can be suspended in air are prone to such explosions. But at 2- to 4-mm average diameters, the granules used in TXM are up to four times larger than the maximum size at which dust explosions occur.

When processing Mg to make parts, you have to convert material into liquid form by heating it above the ignition temperature. The most common method to prevent ignition is to use an inert gas as a protective atmosphere to keep air from getting to the molten metal. In diecasting, sulfur hexofluoride is used over the top of the melt. In TXM, argon is injected into the screw. In both cases, oxygen is prevented from contacting the melt.

A related issue with Mg is that it has a high flame temperature, so that most of the materials used to put out fires, such as water or CO2, may dissociate. Water, for example, breaks down into hydrogen and oxygen, both of which feed the fire. CO2 breaks down into oxygen and CO, neither of which are good choices. The good news is that materials for extinguishing Mg fires are readily available. These include salt-based or graphite-based powders, known as Class D.