Six members of the Washington Capitals will be on the ice here Wednesday night when the United States and Sweden meet in the semifinals of the Canada Cup.

Defenseman Rod Langway and forwards Dave Christian, Bob Carpenter and Bryan Erickson have played important roles for Team USA, runner-up to the unbeaten Soviet Union in the round-robin segment.

Defenseman Peter Andersson and center Bengt Gustafsson represent surprising Sweden, which rebounded from an opening 7-1 rout by Team USA to finish third in the six-team round robin.

The seventh Capital in the Cup, right wing Mike Gartner, will see his next action Thursday in Calgary, when Team Canada faces the Soviets in the other semifinal.

The two winners begin a best-of-three final series in Calgary Sunday. The Canadians, following their 6-3 loss to the Soviet Union Monday night, felt that a one-game semifinal shot against the powerful U.S.S.R. team might provide a better chance of success than the need to win twice in the final.

"It might be a blessing in disguise, having a one-game thing against the Russians," Gartner said. "It's the opposite of 1981, when Canada was unbeaten in the tournament until the final and the Russians won it (8-1).

"Now the pressure's on them. We have our backs against the wall, but that seems to be when we play best."

Team Canada certainly was not at its best Monday. It was limited to 17 shots by the Soviets and became disorganized after Irek Gimaev and Anatoli Semyonov scored 19 seconds apart in the second period to dissolve a 2-2 tie.

Nevertheless, Coach Glen Sather purported to be pleased. He joked about pregame speculation that the Soviets might throw the game to obtain a more favorable semifinal matchup against Sweden.

"We fixed the game tonight; that was our strategy. We just wanted to play them one game," Sather said, obviously in jest. "It is a positive way to look at it, though. We only have to play them once and if we win, we're in the final.

"You've got to feel good about the situation. Our team came out of the game with a positive outlook. We got better as the game went on and we had a lot of good chances to score. Mike Bossy had three chances in the third period and missed them. I don't think he'll miss three like that again."

Although Canada has scored 23 goals, high for the tournament, it repeatedly struggles in its own end. Kevin Lowe is the only one of four Edmonton defensemen who seems able to cope with the Soviets' free-wheeling moves. Montreal's Larry Robinson is lacking in speed and even Boston's Ray Bourque, an NHL first-team all-star, was made to look like a rookie by Sergei Yashin as he set up Semyonov's goal.

The seventh defender, Doug Wilson of Chicago, missed Monday's game with bruised knees and is doubtful for Thursday.

Defense, on the other hand, is the strength for Team USA, which has permitted only 13 goals in five games. Goalie Tom Barrasso of Buffalo and defenseman Langway are probably the only non-Soviet players who would make an all-tournament team at this stage. Although Barrasso sat out Monday's 6-4 victory over West Germany resting a bruised knee, he is expected to be ready for Sweden.

Gustafsson also enjoyed a night off Monday as Sweden rallied to beat Czechoslovakia, 4-2. Gustafsson, averaging a point a game, has been a key figure in the Swedes' resurgence.

Gustafsson tangled with Edmonton's Wayne Gretzky during Sweden's earlier 4-2 upset of Canada. The result lifted the spirits of the Swedes, generally regarded as the pacifists of international hockey.

If the Swedes have restored lost pride, the United States has established itself as a world power, seemingly more fitted than Canada to challenge the powerful Soviets.

"We have a great defensive club," Langway said. "We have the best goalie in the world and our defense is solid, even though we're missing some key players (injured defensemen Mark Howe of Philadelphia and the New York Islanders' Ken Morrow). The guys we have are very mobile.

"And our forwards are very responsible and unselfish. We have the talent and we can outwork anybody."

Team USA has impressed Soviet Coach Victor Tikhonov.

"The American team in this tournament is at a very high level," Tikhonov said. "Any game with this team is an exciting and interesting game. I have always had this opinion of American hockey teams."