As hundreds of thousands of steelworkers voted nationwide today to decide a bitter power struggle for control of their huge union, a 25-year maintenance man at Bethlehem Steel's plant here lingered outside the polling place, musing about the cost of his new car. A third man glared at a woman passing out literature nearby and grumbled about "Commie agitators."

The election had been billed as an epic struggle, pitting Lloyd McBride, 60, tapped by the union heirarchy to succeed retiring United Steelworkers President I. W. Abel, against a 38-year-old insurgent, Edward Sadlowski, an advocate of more democracy and militancy in the 1.4 million-member union, the AFL-CIO's largest.

Both government and industry wer watching nervously from the sidelines, fearful that an indecisive or contested result - leaving in doubt the union's stand on such major issues as its "no-strike" policy - could complicate steel industry negotiations scheduled to begin Monday.

Concern about voting irregularities was running so strong that Joseph Kotelchuck, president of Baltimore Local 2610, decided to call the steelworkers' international headquarters in Pittsburgh before admitting a television crew to the room where workers were voting.

But the rank and file of Local 2610, whose 10,000 members man the coke ovens and blast furnaces at Bethlehem's massive Sparrows Point plant here, was taking it all in stride as workers turned out to vote at the union hall this morning.

Upstairs in the union's small coffee room, John Fair, a grievance committeeman who supports Sadlowski, and Joe Black, a shop steward wearing a McBride button, reflected on the apparently apathy.

"I've been in the steel mills 30 years and in the union here 30 years," said Black, "but people who've been here 15 years think everything they've got is a gift from the company, not the work of the union . . . They're making good money, their pockets are full, their bellies are full, and they don't care about the union anymore."

"That's right; Joe's right," said Fair. "Years ago, when the boss was on our backs, they caree. Now they say, 'John, you do.' They've grown lazy."

Black and Fair also agreed that the union's international leadership had lost touch with the rank and file.

"The international is really bad news at Sparrows Point," conceded Black, although he was backing its chosen candidate, McBride, for president. "I think our international people are so busy they don't have time to go into the [union] halls and really talk to poeple. It's too big a job, I guess." Black said this estrangement, which Sadlowski has hammered upon, is one reason that Sadlowski was apparently pulling heavy support in Local 2610.

What brought Fair and Black into sharpest disagreement was what Fair referred to as Sadlowski's "radicalism."

Sadlowski once joined actress Jane Fonda in a Vietnam war protest match on the White House. Said Black: "as far as I'm concerned, Jane Fonda that's a person who shouldn't even be allowed in the country."

But Fair retorted, "More of us should have been radical and spoken up. Then not so may people would have been killed . . . Some people look at radicalism as bad. I look on it as a way of getting things changed that need to be changed."

Fair, despite his support for Sadlwoski, conceded that he was "satisfied to a degree with the way the union's been run." What bothered him, he said, was the idea that Abel could handpick his successor.

"Nobody's born to be president," he said. "Anyone who does his homework should be able to run and win. If we ever get to the point we don't have a democratic union, we might well fold up."

Fair and Black agreed, however, that probably not much would change, no matter who was elected. "Can anyone make much change?" asked Fair pessimistically.

Informal early returns from the union's more than 5,000 locals began trickling in tonight but official tallies are not required to be sent to the union's Pittsburg headquarters until Feb. 18. Complaints about voting irregularities may be filed during that period, and appeals from union decisions can be taken to the Labor Department which can call a new election if laws governing union election are violated.

Meanwhile, contract negotiations - starting with a formal presentation of position by the union on Monday - are expected to proceed on schedule, partly because the "no-strike" agreement calls for arbitration of issues that remain unresolved as of April 7. Both industry and the union are understood to want to avoid arbitration.