When the Commerce Department last week ruled that European governments had unfairly subsidized their steel companies, the ailing U.S. steel industry may have interpreted the decision as an elixir for better health.

But industry analysts are cautioning that the Commerce Department's prescription may turn out to be only a placebo, or that it could set up the industry for a relapse later on.

"By winning these cases, the steel industry makes it less likely that they can solve their other problems" because there will be less pressure to do so, said Charles Bradford, an analyst for Merrill Lynch. Instead of unfairly priced imports, the steel industry's problem "is the shape of the U.S. economy and the recession," said Drexel Burnham Lambert analyst David Healy.

Analysts said the decision favoring the steel industry relieves the pressure on steelworkers to reopen negotiations and accept lower wages and benefits. One of the industry's major problems is high labor costs, which average $22 an hour per worker, the highest for U.S. manufacturing workers, the analysts said.

While the labor union and the company management recognize that old, unproductive work rules and high wages are a great problem, "I don't think the average blue-collar steel-mill workers believe they are the problem," Bradford said.

A larger problem, however, is that Canadian or Korean steel companies, which are extremely efficient and have been relatively prudent in their exports to the United States, could fill the void left by the European companies affected by Commerce's action. If the Canadians or Koreans don't take over, those companies that are effectively barred from shipping steel here can change their product mix to goods, not covered by Commerce's action, which are more sophisticated and generate more profit to the foreign steelmakers, analysts said.

Commerce filed its decision against the nine countries at midnight Thursday after 11th-hour talks with the U.S. steel industry and the European Economic Community failed to produce a settlement on 28 cases that accused the foreign companies of illegally subsidizing their steel industries. The complaints had been filed by seven of the nation's largest steelmakers, led by U.S. Steel Corp.

The unprecedented complaints were filed following high levels of market penetration by foreign steelmakers last year. Steel imports were at a record high in January, but have declined in the last four months. Still, steelmakers said foreign producers unfairly captured a record 22.8 percent of the U.S. market during the first quarter this year and contributed to the layoffs, as of last week, of at least 106,000 steelworkers. An additional 28,000 were working short weeks.

The Commerce action affects 3.9 million tons of 1981 steel imports valued at $1.4 billion; that is, about 20 percent of U.S. steel imports and about 4 percent of U.S. steel consumption.

The Commerce action requires U.S. importers to immediately post cash or a bond equal to the estimated subsidy to ensure that payment of the countervailing duties is made after a final determination this fall. The subsidies range from less than one percent to more than 40 percent.

The cases now go to the International Trade Commission, which will decide whether the domestic industry was injured by the foreign trade practices. In addition, the government still has to decide other steel-subsidy cases and complaints that foreign steelmakers violated U.S. antidumping statutes by selling steel here at prices below those they charge in their home countries.

The effect of the decision is to make foreign steel prohibitive in price and make importers wary of buying products affected by the decision.

"Most steel producers are currently losing money on each ton of steel they sell and the industry is operating at only 42.5 percent of capacity, the lowest rate since 1938," Commerce Secretary Malcolm Baldrige said in announcing the decision. Steel mills should operate at about 70 percent capacity to make a profit, analysts have said.

But Baldrige also acknowledged that the administration's decision last week will not be enough to make a sick industry well.

"Offsetting the subsidized advantages certain foreign competitors enjoy will not by itself restore the U.S. steel industry to health," Baldrige said. "The industry must increase its productivity and competitiveness."

Bradford said a result of the decision could be the emergence of more German products sold here, which were found to have little or no subsidies, to replace the British part of the market. British Steel Corp. was found to have the largest government subsidy, exceeding 40 percent. The Dutch, who also had low levels of subsidy, could also fill the British void, Bradford said.

Another scenario painted by Bradford is a switch by foreign producers affected by the decision from less sophisticated products, such as plate, to nails, bolts, nuts and other goods that provide more profit per item to steelmakers. "In this particular case" of nails and bolts, "we have already seen foreign producers make inroads," Bradford said. The decision "could accentuate that trend."

On the other hand, as a result of the decision steel companies should be able to raise their prices, which Bradford said they need to do badly. American producers have been discounting their prices to match those of the unfairly priced imports. Analysts said steel price increases wouldn't cause much of a change in the cost of goods such as appliances, cars or housing, whose steel costs are a small percentage of their prices.

However, the American Institute for Imported Steel estimates that American consumers will pay more than $5 billion more annually because of the duties. "This action has eliminated the only competition faced by domestic steel mills," said Marcel Loeb, institute president. The subsidy action "will embargo certain steel imports by pricing them out of the market and increase prices of both imports and American steel products."

Drexel's Healy said some production may shift back to American steelmakers, but it will probably have no effect because of the recession. "It may raise import prices to some extent and shift some tonnage back" to American producers, Healy said. If some business shifted back to the United States, "it wouldn't make much difference."

The industry's major problem besides high labor costs and low productivity is the economic recession, Healy said.

"U.S. steel workers and steel producers have long stated they can compete with anyone on a fair basis," Deputy Assistant Secretary of Commerce Gary Horlick said. Now, with the beginning of actions to eliminate unfair foreign trade, the U.S. industry may have the chance to prove it was right.