Gerdau Ameristeel owns and operates 15 steel mini mills in North America.
Some big steel makers have tried to see off the threat by running their own mini-mills.
The big, integrated steel makers pooh-poohed the tiny mini-mills when they started up in the 1970s.
Mini-mills have been doing well: their share of the market has quintupled over the past 25 years.
ECONOMIST: Why protecting American steel is such a rotten idea
The non-union mini-mills have grown fivefold, and now claim nearly half the market.
Nucor ( NUE) is the largest U.S. operator of mini-mills, smaller steel facilities that use scrap as their raw material.
On top of their lower labour costs, the mini-mills' electric-arc furnaces are much cheaper to build than iron-ore blast furnaces.
Over the past 25 years, steel from domestic mini-mills has taken far more of the integrated giants' market share than have foreigners.
American steel is really two industries: a group of low-cost, non-unionised mini-mills and an array of unionised, capital- and labour-intensive integrated steel producers.
ECONOMIST: Why protecting American steel is such a rotten idea
Mini-mills still cannot produce the best grades of steel satisfactorily.
Yet mini-mills cannot do it all: there is not enough scrap to satisfy all steel demand, and steel made from scrap is not high enough quality for all uses.
On average, according to World Steel Dynamics, a consultancy, the mini-mills use less than one-third of the labour that the integrated mills need to make a tonne of sheet steel.
Best of all, the mini-mills have a natural hedge against a downturn in steel prices, because the price of scrap steel, their input, rises and falls with their finished product.
应用推荐