President Carter yesterday turned down a request from domestic producers of high-carbon ferrochromium, a chrome alloy used in stainless steel production, for higher tariffs against foreign competition.

Carter overruled a recommendation by the U.S. International Trade Commission, which makes initial tariff determinations, that a 30 percent duty be imposed on sharply rising imports of the chrome alloy from South Africa, Brazil and Yugoslavia.

In a formal notification to Congress which has the power to override the president's determinatiuon. Carter said the tariff increases would not be in the national economic interest because they would add to consumer costs and could prompt other countries to retaliate against U.S. products.

The domestic chrome producers had sought balance the political impact of the issue by reminding Carter of his administration's repeated pledges to increase world pressure on South Africa unless the white minority government changed its apartheid policies.

Sen. Dick Clark (D-Iowa), who called on the Carter administration last week to "actively discourage" American investment in South Africa, said yesterday that he was "very disappointed. The decision is not a step in the direction of putting some distance between ourselves and South Africa, which has certainly not moved toward full participation for all of its citizens."

Clark asserted that imports of the strategic alloy have doubled in five years, in large part because American firms have moved production facilities to South Africa, where black labor is tightly regulated and paid lower wages than white workers receive. The United States imported $70 million worth of the alloy last year, half from South Africa.

The President stressed the free trade aspects of his decision, arguing that the proposed higher tariffs would weaken U.S. leadership in international efforts to reduce trade barriers and make it more difficult for other governments to deny increased protection to their industries.