The six Americans who escaped from Tehran last weekend with Canadian help returned to Washington yesterday for a warm welcome from President Carter and an exuberant outpouring by their State Department colleagues.

The president praised them as "six brave Americans" who he said did not fully realize how much "the people of our country loved them" Carter said after a brief, private talk with them at the White House.

The four men and two women, wearing maple leaf pins to show their gratitude to Canada, were loudly applauded by State Department employes who packed the building's C Street lobby, stairway and balconies to celebrate the homecoming. The crowd waved placards that read "Thanks Canada" in both English and French.

In a brief, solemn statement read by one of the six, consular official Robert G. Anders, the escapees expressed gratitude to the American people and the U.S. government for their support, to Canada for "the risks" it took in helping them escape and to those reporters who knew that the Americans were hiding in Tehran but kept that knowledge secret.

"We are glad to be home and grateful for your concern," Anders said.

In their first public statement since arriving back in the United States on Wednesday, the six Americans provided only what Anders termed a "bare outline" of how they escaped when the U.S. Embassy was stormed by Iranian militants Nov. 4, and how they managed to avoid capture in the three months that followed.

"When the embassy was overrun . . . five of us were working in the consular section at the rear of the embassy compound, some distance from the chancery, where the main attack was centered. Thus, we were able to leave the premises unobserved," Anders said.

"We made our way to our homes or the homes of friends," Anders added. "As the situation became more intense, we were able to move to Canadaian premises, where we remained in hiding.

"Lee Schatz, the agricultural attache, worked in an office off the compound in a building on the same street as the embassy. Thus, he was not trapped with the others and he, too, joined us at the Canadians."

While sketchy, Anders' statement appeared to confirm, at least in broad outline, an account given to The Washington Post by Kim King, an American tourist who also escaped from the consular section Nov. 4 and returned to the United States shortly afterward.

Recalling the events as a "nightmare," King said a group of Americans, including several of those who departed last weekend, were barricaded for 3 1/2 hours in a dimly lit, second-floor consular section before they escaped through a rear door into a deserted back alley.

Anders said the six Americans had agreed not to provide further details of their escape because they wanted "to do nothing which would jeopardize the hostages or our benefactors." Fifty Americans are being held by the militants and three U.S. diplomats are under virtual house arrest at the Iranian Foreign Ministry, according to the State Department.

In addition to Anders and Schatz, the Americans who escaped are consular official Mark J. Lijek; his wife, Cora, a consular assistant; consular official Joseph D. Stafford, and his wife, Kathleen, a consular assistant.

The six, who used Canadian passports and forged Iranian visas in their escape, appeared relaxed yesterday as they spoke briefly with reporters and received their colleagues' welcome, but the brief statement provided little insight into the psychological impact of spending almost three months in hiding.

Amid the ceremonial homecoming were a few notes of humor and some somber reminders of the continuing U.S.-Iran crisis.

Anders drew laughter when he remarked that, during their months in hiding, the diplomats "played Scrabble to the point where some of us could identify the letter on the front by the shape of the grain on the back of the tile."

Canadian charge d'affaires Gilles Mathieu, who was cheered amid shouts of "bravo" in the State Department lobby, also struck a light note when he said, "This morning we got two letters still to transmit" from the U.S. diplomats' families to their hideout in Tehran, "but it won't be necessary, I think, now." The crowd burst into renewed applause.

Anders later spoke of "friends and colleagues" still captive in Tehran, saying, "We must not and will not forget them."

At the White House, Anders handed Carter a maple leaf pin like the ones the returning six were wearing, and the president pinned it on. "They are wearing the maple leaf to express their gratitude to the Canadians who treated them so well and who helped them so much in a courageous way," Carter said.

The six also met privately with Secretary of State Cyrus R. Vance. His wife, Gay, had welcomed them earlier in the day at Andrews Air Force Base as U.S. and Canadian flags flapped in the background.