I need a list of all the cities in the world that are - or were -
based around the production steel. i.e Sheffield, UK. Anshan City,
China. Fagersta, Sweden. The Ruhr Cities, Germany. Pittsburgh, US.
Hamilton, Canada. The fact that they are (or were) centred on steel is
more important than their size. I need a list of around 30 cities -
covering the whole world. Maybe the main steel city in most of the
major countries, or the 2/3 main ones in big countries (China/US). The
list should be just the name of the city and then the country.

I think Newcastle in New South Wales, Australia may have been centred
around the steel industry.
However, BHP has pulled out of there.

http://locopage.railpage.org.au/bhp.html

Port Kembla and Whyalla are still operating.

Bethlehem, PA was one of the original homes of steelmaking in the U.S.
and was the primary industry there until the 90's.

Misratah, Lybia
http://lexicorient.com/e.o/misratah.htm

Panzhihua, China
http://en.wikipedia.org/wiki/Panzhihua


Ooops- gotta go, kid is crying. Try your local library's subscription
databases. If they have a subscription to a good business database you
can do a company search for SIC code 3312 and extrapolate from there
for current leaders.

Good luck!

Eisenhüttenstadt on the eastern border of Germany certainly qualifies.
http://www.ff.uni-lj.si/oddelki/geo/publikacije/dela/files/dela_21/035%20loetcherer.pdf

Significant is that Eisenhüttenstadt ("Iron Foundry City") is not a
natural place for such an industry.  The iron ore and coal necessary
were shipped from Russia and Poland, respectively, the Russian/Soviet
Zone of Germany being short of an existing source for iron and steel. 
The original name of Stalinstadt suggests the close cooperation with
the Soviet Union.

Newport in South Wales has the Llanwern steelworks and the Whitehead's
strip mill, now both gone.

Cardiff had the East Moors plant.

And Blaenavon was famous as an iron town.

Gary, Indiana
Weirton, West Virginia
Aliquippa, Pennsylvania
Granite City, Illinois
Homestead, Pennsylvania
Panzhihua, China
Liège, Belgium
Charleroi, Belgium
Misratah, Lybia
Dunkirk, France
Fos-sur-Mer, France
Rotterdam, Netherlands 
Eisenhüttenstadt, Germany
Gwangyang, South Korea
Port Talbot, South Wales
Scunthorpe, England

Beaumont, Texas
Cherepovets, Russia
Bhilai, India
Rourkela, India


Okay, I am tired now, but it was fun helping you out.  Hope someone
answers you.  And by the way, to check the validity of the cities I
provided you with all you need to do it go to Wikipedia... they'll do
the rest.

If size doesn't matter that much I could always recomend the little
known town of Peine in northern Germany to round out your list. It
mostly came to my mind when I read your querry because it used to bill
itself as the "Stahlstadt im Wandel" or a "Steel City in
Transformation" to reflect the fact that the steel industry was no
longer as impoartant there as it used to be. They still got a big
modern electro-steel-works in the center of the city though.

Netherlands: IJmuiden (corus) not Rotterdam