Arcelor's board supports the deal and it is expected to be finalized at the end of July, although there is some opposition from shareholders and investors.
Severstal, which is valued at $16.6 billion, is one of several Russian companies seeking a new international role and also supported by the Kremlin.
Meet The New Boss
Until now, Aleksei Mordashov was largely unknown in the West. In his forties, a billionaire son of steel workers, he has headed Severstal since 1996.
If the merger takes place, Mordashov will acquire more than one-third of what would be the biggest steelmaker in the world. In return, Arcelor will buy the nearly 90 percent stake in Severstal owned by Mordashov. The move would most likely prevent a hostile bid for Arcelor by Rotterdam-based Mittal Steel.
As the non-executive president of the Arcelor board, Mordashov would have the right to nominate six of the total of 18 directors.
Arcelor's Chairman and CEO Guy Dolle portrays the deal as a consolidation of the steel industry in a globalized world.
"We, Severstal and Arcelor, have both shown that we are much stronger together than apart," he said. "We have shown that together Arcelor and Severstal we could become even stronger, to give an answer to the challenge, challenge of globalization."
Ambitious Plans
Mordashov told Reuters news agency that the new company has ambitious plans to carry out further mergers and takeovers.
It's the latest example of what some analysts are saying is Russia seeking to expand its business influence abroad.
And it's not only Mordashov who is purchasing stakes of Western steel companies. According to the "Financial Times" on May 30, another Russian oligarch, Roman Abramovich, is thinking along the same lines.
Abramovich, Russia's richest man and owner of the British Chelsea soccer club, is due to buy a 40 percent stake in Russia's largest steel producer Evraz. Reports say the purchase could hasten talks between Evraz and Corus, the Anglo-Dutch steelmaker.