What are Graphite Electrodes?

In chlor-alkali manufacturing based on electrolysis of brine, graphite electrodes are used as the anode with mercury as the cathode.

Garaphite electrodes are also used in the EDM (electrical discharge machining ) process. EDM is used in machining particularly in mold making when there is a need to cut a sharp corner which cannot be done with a round cutter or a very delicate shaped cavity or deep and narrow cut which a conventional cutter cannot reach.

Useful in cutting female splines, also. Graphite electrodes are machined in the shape of the hole they're intended to cut using EDM tools. To the original poster: google "EDM" for more information. There are a wealth of sites online which provide a wealth of information on this topic.

During the Second World's War and possibly before, Graphite Electrodes were used in SEARCHLIGHTS that produced extremely BRILLIANT LIGHT. The light produced was so very brilliant that the operator had to wear "Welders Goggles" for eye protection while adjusting the "ARC" point of the light's 1/2 inch diameter graphite/carbon rods.

After ignition, a "Clockwork mechanism" delivered/fed the rods at a uniform rate until the rod in use had expired. I am sure that today's applications would include "High-Temperature" cutting of ferrous metals and such but in a much more miniature application. BTW, Power required to provide the high-current was supplied by a large gasolene engine driving a generator that was installed on it's own towable trailer.

Graphite electrodes are also used in arc furnaces that melt steel. The arc furnaces can be single phase where the potential is from the electrode to the shell of the furnace or they can be three phase where the potential is between 3 electrodes. The heat that is generated by the arc is at a high enough temperature to melt most steel.

Electrodes are manufactured in sizes ranging from 18" in diameter to 72" in diameter, depending on the application. The length can range from 48" to 72". Once the electrode is formed and baked in a furnace for hardness, it is machined with female threads at both ends. A matching socket is also machined and sold with the electrode to attach two electrodes together while the electrode is being consumed within the arc furnace.

Consumption rates and life are difficult to determine because of the following variables:

Applied voltage

Applied current

Distance from electrode to electrode or electrode to furnace shell

Type of steel that is being melted

Amount of air or oxygen that is applied

A good comparison would be like trying to determine how long it takes to burn a welding rod down to the end.

I hope this answers your question.

Take care and good luck!

Jeff

Just to keep it simple;....... Graphite is a structure of conductive carbon atoms. Sort of like diamond but in a different molecular shape. Graphite is a conductor of electricity and typically used in high voltage applications. As far as its life span goes, it depends on the application. Typical rule of thumb, would be if it exposed to an electric arc it will not last too long. What ever your application is I would sugest keep spares! try the first set to failure and then develope your own time line of usage to failure results. Ta!

Your question is referring to the graphite electrodes and nippels used in arc furnaces of the steel making plants as described by above responders.we are the supplier of graphite electrodes and nippels.

Actually,consumption rate of the graphite electrode consumed during production of one ton of steel reflects the quality of the graphite electrode.It depends on many variables including the type,quality, level of current of the arc furnace as well.The less consumption of electrode per ton of steel produces,the better quality the electrode is.

Electrodes are mainly classified as UHP(Ultra High Power), HP(High Power), RP,SP...etc.quality grades.UHPs are best quality and expensive, HP is cheaper with moderate quality,RP,SP and others with lower quality and not widely used.UHP can sustain maximum current values, HP, RP,SP can stand with moderate current values.Using HP or lower grade under high current values will result with the breakage of the graphite electrode in the furnace during steel production and will harm the production considerably.

In average one arc furnace spends 400-500Tons of graphite electrode per year under continuous steel production.Nippel is the threaded attachement at the end of the graphite electrode.

Great response. Never saw nipples on EDM electrodes, so your presumption of question dealing with steelmaking arc furnace electrodes is probably spot on.

Consumption of electrodes per ton of steel used might be better metric than tons of electrodes per year, its the tonnage and mix/morphology of the scrap to be melted that are the cost drivers of electrode consumption.

You are right on with the importance of the quality of electrodes as well.

milo

we are the leading supplier in isostatic graphite industry.

A graphite electrode is also used for arc gouging of cast iron and other metals. This is an old technology but effective where other methods are not available or effective.

Electrodes made out of graphite. Usually used when metal electrodes cannot be used, such as when the electrodes need to be in contact with acids, or where friction with moving parts will result in rapid wear of metal electrodes. Graphite electrodes are self lubricating as graphite itself is a good natural lubricant.

A good point made here as MOTOR BRUSHES are made of GRAPHITE! Those days of yesteryear are now behind us where we all had to watch the length/condition of our GENERATOR BRUSHES for any need for replacement, many miniature DC motor makers still are using graphite brushes. "MG" power sets use them as well. Alternators also make use of GRAPHITE brushes and many a good alternator has been discarded only because brushes were worn, lost spring tension, or were simply "Stuck" in their holders.due to atmospheric/airborne contaminants.

is this the same graphite electrode used in cupola melt? or is this the same graphite used in foundry to raise carbon content in cast iron melts?