Armand Hammer, who had a 1 1/2-hour private interview in December with the Soviet leader, said last night in a speech that Konstantin Chernenko indicated to him that the Soviets were likely to agree to arms-control inspections. Hammer, at a black-tie dinner for 180 in his honor at the Corcoran Gallery of Art, called for a summit meeting between Chernenko and President Reagan because "the danger is so great, so unthinkable.

"President Reagan is at the height of his power," Hammer said. "President Chernenko is at the height of his. If they met, the history of the world would be changed."

His remark on arms-control inspections came quickly in off-the-cuff remarks at the end of a prepared speech. He did not elaborate.

Hammer, the 86-year-old American capitalist and philanthropist, has, with the exception of the Stalin years, been a close friend of Soviet leaders since he made a fast friend of Lenin by bringing wheat to feed the starving Russians after the Revolution. Last night, Hammer was honored by being named a Corcoran lifetime trustee and awarded the William Wilson Corcoran gold medal, the sixth person in the gallery's 116 years to be so honored. In 1979, Hammer gave the Corcoran $1.15 million, and in the '80s, Daumier bronzes and lithographs.

"Cherneko is a warm, human person," Hammer said. "He said he would be willing to meet with President Reagan but that there was no use unless they could have something to show for it. He pointed out that the countries have agreed on three treaties, but none have ever been ratified. If only one was ratified, and that the arms control treaty, he thought it would be worthwhile to have a summit.

"I am convinced Reagan wants peace. If we can get them to sit down together, learn to like and trust each other, the problems between us can be solved." Hammer said he thought "our great secretary of State, George Shultz" and Soviet Foreign Minister Andrei Gromyko had laid the groundwork for a summit. And Hammer urged not just one summit, but two a year, in Moscow and Washington.

Earlier, in a conversation, Hammer said he thought chances for peace were "much better than a year ago." As for Chernenko's ill health, Hammer said, "He has emphysema, but he's in good shape."

David Lloyd Kreeger, president of the Corcoran board, announced that he and four other Corcoran life trustees (Frank Saul, John Firestone, Michael Rea and Gilbert Kinney) had matched an additional gift of $500,000 by Hammer with $1,750,000 of their own money.

Trial lawyer Louis Nizer, a longtime friend of Hammer's, said, "I suggest to Defense Secretary Caspar Weinberger who was sitting at a nearby table that he take the suggestion to President Reagan that he follow Corcoran President Kreeger's example and pay the U.S. deficit himself."