Few people remember the clash with Canada several years ago, started by three U.S. companies claiming they were treated unfairly by their northern neighbors.

Months of feuding centered around an item nearing apple pie in American patriotism -- ice cream sandwiches.

Then there was the attack against the Australians, which almost drew in the Italians, over canned Bartlett pears and the more celebrated battle of the Polish golf carts, which gave the Carter administration much heat and little humor.

What kind of conflicts are these? They are all dumping cases, which have increased more rapidly in the past six years than at any time since the International Trade Commission was given partial authority over them in 1954.

Dumping is the importing of goods at prices below their production costs that subsequently materially injure or threaten to injure the domestic market.

The cases have increased partly because trade has become an important aspect of American life, the public is concerned with reducing the trade deficit and the nation's business owners feel they need more protection from imports to earn profits and reduce unemployment, particularly during bleak economic times, trade experts said. Also, agencies hearing these cases recently have tended to side more with American firms filing complaints because of relaxed rules, government officials said.

More companies are also aware that they may get some protection from foreign competition by filing complaints and even some lawyers specializing in trade see months of bureaucratic disputes as a way to ease competition for their clients.

"There are some lawyers who will file a case to gum up trade for six months or so," one government trade official said.

The products involved range from chemicals from Japan to water circulating pumps from the United Kingdom, from dried eggs and bicycle speedomoters to plastic mattress handles, dehydrated mashed potatoes and automobiles.

While some items in dispute may appear frivolous, many can result in heightened tensions between nations, informal recriminations, enormous financial consequences that eventually are passed on to consumers and "ill feelings," as one government trade expert put it.

"There is always a country that cares about a case and they'll tell the State Department about it or the office of the U.S. Trade Representative to 'fix it'," said John Greenwald, a deputy assistant secretary for import administration at the Commerce Department, which shares dumping authority with ITC.

"These cables" between the governments "go on all the time. But, you shouldn't leap to the conclusion that we fix these cases, because we don't."

Commerce gets calls from the White House, the Ways and Means committees and others, Greenwald said. "Sen. X is interested in this. Make sure you apply the law," meaning in favor of the senator's side, Greenwald said he is told. "It happens on both sides. Our job is not to pay attention to these things."

For overall turmoil and disruption, no dumping case can top the current stirrings between U.S. Steel and steel producers in seven European Economic Community countries, who U.S. Steel accused of dumping. An ITC official called the steel case the most complicated case to come before the commission.

Dumping and the rather obscure ITC, which determines the injury part of dumping, have come to the forefront in the news lately because of the steel case, dumping charges surrounding the importation of Mexican tomatoes and other winter vegetables and Japanese color television sets.

The Mexicans were cleared of dumping charges and the Commerce Department, which assesses dumping duties, last week ordered Japanese television importers to pay about $66 million in dumping duties accrued from 1971 to April 1, 1979.

The current conflict between U.S. Steel and seven European countries is threatening to induce a trade war and is creating tensions between the U.S. and the Common Market. The final outcome of the steel battle, which is not expected for months, will affect millions of dollars in possible dumping duties against importers and could raise the price of steel products here.

The ITC last Thursday said that it found a "reasonable indication" that the U.S. steel industry was injured by low-priced imports. The case now goes to the Commerce Department to determine whether the imports were brought in at prices below their fair value.

Since 1954 when some of the authority for investigating dumping cases was given to the ITC, 170 cases have been completed, 117 of which have occurred in the past 10 years. The country with the most dumping complaints against it is Japan with 52, followed by Canada with 38. More than half of the dumping complaints against Japan have been made since 1973.

The companies filing the complaints must first file them with the ITC and the Commerce Department. The case goes back and forth between the ITC, which preliminarily and finally determines injury, and Commerce, which decides whether the products were introduced at prices below their fair value and assesses dumping duties.

These often lengthy battles are fought not with bullets and bombardiers but with battalions of lawbooks and lawyers bludgeoning each other with facts, figures and finesse.

For example, in the 1971 dispute over ice cream sandwich wafers, which the U.S. companies claimed were being dumped here by the Canadians, the Americans introduced facts such as: "It is undisputed that ice cream sandwich wafers have no close substitutes," and, "An ice cream sandwich manufacturer does not switch to Ritz crackers or chocolate chip cookies" when economic conditions change.

On the other hand, these cases also involve sensitive relations between nations although decisions are supposed to be based solely on the facts and not foreign policy or politics.

For example, during recent filings by American firms in the 1975 Polish golf cart case, lawyers introduced a letter from Assistant Treasury Secretary Gerald L. Parsky to the Polish vice minister of foreign trade and shipping that the U.S. government officials "understand your concern over the antidumping case involving golf carts from Poland and are sympathetic. We too hope that a mutually acceptable solution to this case will be forthcoming. . . . Let me again assure you, however, that the U.S. antidumping statute is applied in a nondiscriminatory manner with every care given to ensuring due process to all parties concerned and that we will make every effort to reach an acceptable solution in this case. We attach a great importance to the continued expansion of U.S.-Polish economic relations."

The Poles have asked for a review of the 1975 dumping decision against them, claiming that circumstances have changed and the U.S. firms oppose it.

While trade experts are speculating that a trade war may result from the ITC's ruling in the steel case, the countries involved are prohibited from retaliating in dumping cases under the General Agreement on Tariffs and Trade.

While foreign producers may not retaliate officially, they may claim that the antidumping action was illegal or the decision-making by the U.S. agencies was faulty and then turn around and impose trade actions on our exports of soybeans and textiles, Greenwald said. The United States is big in soybean exports, he added.

One government official recalled the Great Chicken War, which didn't start from a dumping dispute, but is illustrative of what can happen. When Europeans removed certain tariff concessions from imported U.S. frozen chickens the United States, in return, removed concessions from imported European brandy and Volkswagen cars, the official said. "Enormous amounts of money were involved," he said.

Some of the dumping cases begin when economic conditions change here and abroad. For example, traditionally, when the economic climate worsens here, U.S. firms seek more protection, trade experts said. When other markets are closed to foreign producers, they often seek out Americans, some domestic producers claim.

The Bartlett pear affair is a good example. U.S. canned Bartlett pear producers claimed in 1971 that the Australians were dumping their pears on East Coast markets because the United Kingdom, with which it did most of its pear trade, increased its tariffs on Australian pears from 0.0 to 24 percent when it joined the European Economic Community.

But the Australians claimed their pears were cheaper because they were inferior to those grown here and the Americans were suffering not from their product but from competition from canned cling peaches.

But the domestic pears won against their foreign peers when a pair of ITC commissioners voted for them, a pair against them and a pair abstained.