Steel imports from the European Economic Community into the United States increased 66.8 percent last year over 1980, adding fuel to arguments by U.S. steel makers that the Europeans are hurting their business.

Imports of all steel products from the EEC--except pipe, tube and semifinished products--increased 27.4 percent over shipments in 1980, the Commerce Department said.

Pipe and tube goods are in great demand in the United States because they are used in the booming oil drilling business and cannot be supplied adequately by U.S. steel makers.

The American firms also import large amounts of semifinished steel products to reduce costs in making finished steel products.

Next week, European steel makers will defend themselves in proceedings before the International Trade Commission against complaints by U.S. steel makers that the Europeans dumped steel here, that it is sold at less than fair value, and that Europeans sold government-subsidized steel in the United States, hurting U.S. steel makers in the process.

A steel industry analyst said yesterday the large increases in EEC imports will not help the Europeans next week. Imports from the EEC rose while U.S. industry steel shipments declined, the analyst said. Most of the domestic industry's business was made in the beginning of the year and declined precipitously during the second half, the analyst said.

Total steel imports, excluding pipe, tube and semifinished products, increased by 981,000 tons, or 8.5 percent from 1980 to 1981, Commerce said. "That increase was accounted for by the EEC," according to a Commerce statement. Imports from the EEC increased 989,000 tons, or 27.4 percent during that period, Commerce said.

While steel imports from the EEC increased, those from Japan last year dropped 13.9 percent, and those from Canada declined 2.9 percent, Commerce said.

Total steel imports, including pipe, tube and semifinished steel, were 19.9 million net tons, a 28.4 percent increase over 15.5 million net tons in 1980. The record for imports was set in 1978 when they reached 21.1 million net tons, 5.9 percent below last year's levels, Commerce said.