AMERICAN steel changed the world over the past century - and now the world is changing American steel. Both statements are true. But the last half of the equation may not mean what most pundits think.
Instead of a world in which cheap South Korean and Brazilian steel doom the great blast furnaces of America and Europe, we may be moving toward a world revolutionized by new steel casting processes. It's a world in which the winners are likely to be manufacturers of specialty steels made in relatively low-cost, small foundries close to local markets.
Like many modern factories, these sheet steel casting foundries will be able to change quickly from one product to another. Some are already able to cast steel as thin as foil. They are able to produce ribbons or sheets of it at the prodigious rate of 20 football-field lengths per minute - and able to cool down the molten metal in milliseconds. Other factories will tackle thicker steel sheets cast to order.
The face of civilization has been radically altered since the mid-19th century by skyscrapers, cars, trains, harvesters, supertankers, pipelines, bridges, tanks, submarines, refrigerators, ball bearings, and myriad other steel-dependent products. And now global steel overproduction, along with wide steelworker wage differences, apparently are altering the strategic map of steel power. The common wisdom is that South Korea (average steelworker hourly wage plus fringe benefits: $1.96) is beating the socks off the old steel giant, America (equivalent wage plus benefits: $22.24). Uncle Sam is supposedly losing his rust belt.
Those aren't the only figures on which the common wisdom is built. Steel imports are rising in the US (19.6 percent of the total supply in the first nine months of 1983; 26.1 percent in the same period of 1984, climbing to 28.9 percent in September). Steel jobs are declining, despite occasional ups among the downs. White-collar jobs have shrunk at a more rapid rate than blue-collar ones.
Dramatic stories abound of reinforcing rods traveling 7,000 miles and still being cheaper than the same product made by American competitors located within a few miles of a construction site.
But those statistics and stories are likely to change in the next decade or two. The reason: a Rube Goldberg array of machine designs with spinning rollers, drums, spray jets of molten steel, fast-moving belts, and high-velocity cooling water. These new prototype machines are designed to produce extraordinarily thin sheets, continuous slabs, or better-quality alloy sheets faster and at lower cost than the old process of pouring thick slabs or ingots from a giant cauldron , then hot-rolling and cold-rolling them to smaller size.
Some of the new thin-strip casters are in commercial operation. Most are still in the laboratory test stage. There are still technical problems to be solved with some of the thicker gauges of metal - problems of impurities, granular structure, edge cracking, and surface flaws. But the outlook is decidedly hopeful. The US Department of Energy signed a contract this summer with Bethlehem Steel and US Steel to develop and build a prototype system to cast one-inch-thick sheets using a system of twin moving belts. This design will be based on the existing Hazlett process, developed by a Vermont inventor and currently in use in Japan. Other processes - some newly invented, some that are improvements on earlier ideas that fell by the wayside - are being tested by other steel firms.
In addition to their implications for world trade competitiveness, the new casting machines promise to cut dramatically both energy costs and the number of man hours per ton of steel.
Credit for my awareness of this revolution-in-the-making is owed to Bruce Merrifield, assistant secretary of commerce for productivity, technology, and innovation; George McManus, steel editor of Iron Age Magazine; and Robert E. Maringer, who is doing high-speed casting research at Battelle Columbus Laboratories in Ohio.
This space is too limited to examine all of the experimental and production processes now being tried in the US, Japan, and Germany. But it may be useful to look at two approaches that show a range of possibilities.
The first is a process that is both dramatic and operational: the so-called rapid solidification technology used by Allied Corporation to cast foil-thin strips only 0.002 of an inch thick. It is this technique that instantly ''freezes'' and rolls the molten metal at speeds of up to 6,000 feet per minute. Imagine a substance thinner than the newspaper in your hand supercooling at a rate of more than a million degrees C. in little more than a second and spewing a foil-like sheet across your living room in perhaps one-fifth of a second.
Then take a look at its qualities: It solidifies so fast that it is in essence a solid liquid with a glassy quality, rather than a large-grained metal. The foil has unusual electrical conducting properties that should make it effective in transformers. A test involving 1,000 transformers is planned. If they behave well and the price for the steel can be brought under $2 a pound, according to Mr. Maringer, there should be a rapid switch to their use.
The second process is the above-mentioned Hazlett method of thin casting. It would aim at effecting labor, cost, and energy savings in steel used in high volume on more prosaic products such as auto bodies and structural parts. In the Hazlett system, molten steel from a furnace is drawn between two steel belts that are cooled by high-velocity streams of water. The capital cost of building a plant may be sharply reduced. Production savings of $35 to $45 a ton are forecast. Energy savings are estimated to be about 3.9 million British thermal units per ton - which explains the Energy Department's interest in the Bethlehem-US Steel project. The two companies see commercial production from the technique about five to 10 years from now.
When American research and development teams began working with the new casting processes, the steel industry hoped for a ''breakthrough'' that would ''leapfrog'' past world competitors. They hoped thus to make the kind of quantum leap that other nations did when they adopted the Austrian-originated oxygen-reduction process in the 1950s. A more realistic appraisal holds that the new processes are more likely to change the future of steel in a way that creates smaller, local, specialized production in many advanced nations. That should still mean a better future for US and European steel.