Arc Furnace

Best? if that's working for you, then it's the best.

Or, do you mean fastest way to melt iron as the best?

Or, do you mean cheapest way to melt iron as the best?

or, do you mean most environmentally friendly way as the best?

For us sales are less and 1 furnace out of 3 is working so not fastest.cheapest sounds good how is the method because our electricity bills are very high. I hope economic friendly is always of costly method. Just out of curiosity is it direct arc furnace you people use?

Be nice if this gentleman got a decent answer.

Firstly, let's establish some facts.

1. What type of iron are you trying to make into steel, Fe2o3, Fe3o4, pellets, lump, direct reduced iron, scrap steel, scrap iron, pig iron, etc., etc?

2. Is the furnace an electric arc furnace? Is the furnacea DC arc? Is the furnace an induction furnace?

3. Do you have steady power supply and at the max rating for the transformers.

4. Would you consider converting the melting practice to a different furnace type, such as oxygen, if you cannot get steady power supply?

5. What is the practice of feeding the furnace, what is the size of the furnace, what materials are you adding to the melt, such as carbon, alumina, alloys?

6. What is the practice of making steel? Do you use ladle refining or do you do it in the melting furnace?

7. What is your tap to tap time from beginning putting materials in the furnace to pouring the hot metal or steel?

8. What products are you making? Rebar, angles, construction grade mat'l or are you making cast parts? Are you making any stainless?

9. Do you use oxygen lancing to control carbon and frothing or a carbon boil? What type of carbon is used?

Please send this information and we will mull it over to see where we stand. Then perhaps we will be able to point the direction.

What part of Kerrala are you in? We adopted a family from Kerrala, northeast, near Cochin. they now live in Bangalore where we lived for 4 years, and in Mangalore.

1.Scrap iron/mild iron using scrap with .1 to .2% carbon and .7% manganese. 2.The furnace is thyrister controlled direct arc furnace. 3.Yes we have steady power supply 15MVA transformer in substation and 5MVA for each furnace.some times the electrode gets dipped and supply trips with an OCB. 4.No 5.We charge the pre heated furnace (15tonne) in 4 to 5 steps 4000kg,3000kg..etc.limestone is added 400kg, After melting we do blocking,taking slag out checking sample with spectrometry 3 times each time if carbon is less coke is added if carbon is more iron ore is added,manganese,silica,limestone is also added as required.Everything is manual with tools and with the help of crane. 6.After tapping to get 1645 degree molten metal is pored in ladle lifted by crane 15ton capacity and billet is made. 7.tap to tap time is 1hr from melting to casting. 8.making billet only. 9.now we are not doing oxygen lancing. well our plant is a govt. Company with a technolngy of 70 's,called Steel Complex Ltd. Feroke,in kozhikode.North side of kerala. looking forward for your suggestion.

1) Almost certainly operating one furnace is more economical than operating two or three part time - heat losses call for using each furnace that is online to the maximum before bring a second furnace on. 2) The last place İ worked operated 4 each 150 mt DC arc furnaces (now more) Of course those transformers were a bit larger! 3) İ assume that being in Kerala you are mainly melting scrap? İf not then you are buying HBİ from one of the İndian plants? 4) İnconsistent power supply is often a problem there - or do you have captive generation? İ expect you are using DC arcs due to insufficient grid available for AC furnaces? Other questions Tom asked would be excellent input to allow us to make suggestions.

Yeah insufficient electrical supply is always a problem.When monthly tariff is exceeded we simply stop production.We dont have a generating plant and DC storage facility.We are depending on KSEB(NALLALAM SUBSTATION).

Do you have a natural gas supply available?

Sir i think we should talk about power later. please tell me is direct arc furnace an efficient technology considering above facts i mentened initially?

They are what you have (the DC arc furnaces) and work perfectly fine. They are what Essar Steel in Gujarat uses and you have no reason to change. What are your specific consumptions? kWh, O2, C in the arc furnace only

Hello Russ. We can't seem to get away from this can we? Drawn to it like bees to honey.

Russ and I use to work together from I guess it 1969/70 at the first commercial DRI Midrex plant. It was part of my job to work with the steel makers in how to use DRI in the EAF, plus as part of the start up engineering group and finish construction super stuff and run the plant, blah, blah, then on to the next plant in Germany, then Canada, then Corporate to head up all the next generation of plants, plus pellet plants, agglomeration plants, steel mills, mines and so on.

It has been our interest to conduct technology transfer or training in all these activities and we've done that ever since and can't let go, after 40 years.

Now we even do it for free in forums like these as it keeps our mind going. The development of the internet is a God's send as we can do it worldwide and open some doors for all.

Thanks everyone for participating.

Tom

tcinc002@aol.com

Right Tom - Can't get away from it! Hard to beşieve the Portland plant was 40 years back! Still enjoy the technology and the potential for improvements - the capacity in the first plants was 20 mtph once in a while - now it is in the 250 mtph range for over 8000 hours per year. Specific consumption of materials has dropped like a rock over time.

I wish to thank you for your input and answers in #6 to my questions in #4.

The short answer to your original question is "if you have sufficient scrap materials, power supply, sources of other feeds, alloys, carbon, etc. And if you have a small market for a limited product line, equal to the availability of scrap, then EAF steel making is considered to be the most efficient, less costly in terms of capital and operating costs. I think our market and steel requirements in the USA and Canada are a good example of this. Whereas, 50 years ago, about the time I became involved in this field of interest, less than 20% of steel was made with EAF. Today over 50% is made with EAF operations. Worldwide the EAF figure, I think may be about 40% and climbing.

There is a need still for the big plants using conventional steel making, the BF, BOF, Sinter plant, Coke plants, Pellet plants, Casting shops and the like, mainly where manufacturing of autos or appliances are done because of the concentrated additional facilities, rolling mills and associated manufacturing lines are needed, making large shops to be more cost effective.

I think that in India the same reasons that exist in the USA for going to the EAF will also be true. As the auto market and appliances market will evidently increase in India, there will also be the increase in scrap. As the scrap availability increases there will be ready made cheap feed for the steel maker. As the growth requirements increase there will be a need for localized smaller steel mills making the required products and using the locally available scrap. So goes the circle.

Their have been major cost saving methods in all steel making technologies over the last 50 years. In the EAF power consumption has krept down from 600 to less than 400 Kw/ton, electrode consumption down by 50 or 60%, EAF use as a melter and the ladle used for refining, quality separation of scrap for known inputs, scrap preheating, use of lower quality scrap with the use of DRI, automated electrics, use of foamy slag to reduce electrode damage and refractory consumption with increased control over gangue removal, and hundreds of other changes to increase efficiency, reduce costs and increase quality. I have also seen manpower reduced in the EAF shop from 1000 people for a complete shop to perhaps 400.

All the while during these changes, there has also been good effective changes for environmental control, "going green" to increased safety and training for personnel. These have been found, finally, to have an effect on increases in production & quality and decreased costs.

There are numerous papers written on all these subjects, available on line as well. If I knew how to add a copy of some of these, I would send some. Perhaps you can look into some of these. A pretty good article or short story for EAF scrap melting is "AISI Electric Arc Furnace Steelmaking" by Jones/Nupro Corp. You can also send to AIST for a copy of the 2 volume books called "Making, Shaping and Treating of Steel". If you cannot find these on line, I will be glad to send them or other information. Ask CR4 for my email address, as they frown on us giving it out.

Hope this helps!

Regards