The European Common Market and Japan will announce an agreement in Brussels today setting minimum import prices for Japanese steel imports by the community, and ending European charges that Japan has been "dumping" steel.

The agreement is similar to a recent decision by the United States to publish a schedule of "reference prices" for steel imports. That was designed to give the U.S. steel industry a measure of protection from foreign imports.

Steel imported below the U.S. "trigger" prices is open to "dumping" charges. "Dumping" refers to sales in an export market either below actual cost, or below the price quoted in the home market of the exporting country.

Under the EC-Japan agreement, Japan agrees not to undercut the so-called "Crisis" minimum prices set by the community by more than 6 percent for ordinary steel products, or 4 percent for speciality steels.

These differentials are allowed to compensate for the additional costs of transportation and insurance and are similar to an agreement signed recently by the EC with the six countries making up the European Free Trade Association.

The EC-Japan agreement is one more sign of a protectionist trend sweeping the industrialized world. Japan also has agreed to voluntary quotas on its auto shipments to Britain and has signed "orderly marketing agreements" with the United States on color television sets. Multilateral agreements bypassing open trading arrangements are in effect for textiles.

Currently, in Geneva, negotiations among the EC, Japan, the United States and other nations for a new round of trade concessions may actually, lead to so-called "selective safeguards," which could extend discriminatory provisions.

The EC-Japan agreement, negotiated betwen Viscount, Davignonof the European Commission and Na ohiro Amaya of the Japanese Ministry of International Trade and Industry, will be explained in terms of "the extraordinary difficulties" currently faced by the European Steel industry.

The two sides plan to say today in a joint announcement that the steel industries in both Japan and Europe have been affected by their head-to-head competition in third markets, and promise unspecified efforts to deal with that situation.

They are expected to consult on all problems arising in steel trade affairs and to avoid any unilateral actions.

The surplus of steel capacity in Europe led to anti-dumping procedures against Japan and other countries. Under the agreement, the suits already initiated against Japan will be dropped, and provisional duties assessed will be refunded.

Japanese authorities have agreed, sources said, to cooperate with the EC to assure successful operation of crisis measures adopted by the community.

Both the Japanese and the Europeans put their stamp of approval on the U.S. trigger price system, and express the hope that it wll lead to a "normalization" of the U.S. steel market, sources said.