The jury in the first Abscam bribery trial heard testimony today that Sen. Harrison A. Williams Jr. (D-N.J.) agreed last year to use his influence as a senator to obtain government contracts for a company in which he would have a hidden interest.

Under questioning by prosecutor Thomas P. Puccio, a convicted con man testified that Williams "said he could get government contracts for titanium," the sole product of the company, in an effort to convince a phony Arab sheik to lend the firm $100 million.

The loan was to buy a mine in Virginia and plant at Savannah, Ga., according to testimony by Melvin Weinberg, the con man who played a key role in the undercover investigation.

The jury in the Brooklyn bribery trial of Rep. Michael (Ozzie) Myers (D-Pa.) also heard a complete tape recording of a June 28, 1979, meeting in which Winberg described how the senator would get an 18 percent share in the titanium company. The undercover informer told the senator how an associate, Alex Feinberg, would take the shares in his name and then endorse them over to the senator.

"When you leave the Senate, whatever time you leave, you put your name. You're the owner, okay?" Weinberg said.

On the tape, Williams answered, "Yea."

Williams, 60, who has not been charged in the Abscam cases, is not heard making promises on the tape to trade his influence for the loan. Neither does he disagree with Weinberg's statements about his role in obtaining the government contracts. In fact he is heard several times on the tape saying "uh-huh" as Weinberg describes the scheme. Weinberg's statements today were the first sworn testimony that the senator was a participant in an Abscam scheme.

Weinberg said he first met the senator on a yacht in Florida in March 1979, and later at a meeting at the Pierre Hotel in New York, before the June 28 meeting with the "sheik" -- actually an undercover FBI agent -- at the Marriott Hotel in Arlington.

At a June 24 meeting, Weinberg testified that Feinberg told him that the senator, who is chairman of the Senate Committee on Labor and Human Resources, was "ready and willing to go."

Sources have said that Williams did attend the June 28 meeting with the "sheik" and did receive stock in the titanium company from FBI agents at a meeting at Kennedy International Airport in New York on Aug. 5, 1979.

Titanium is an extremely valuable element used in aircraft, jet engines, missiles and chemical equipment.

Williams' spokesman said today that the senator thought at the time that the meeting was to discuss a "normal business transaction." Williams has denied any wrongdoing.

Attorneys for Myers and three codefendants played part of the June 28 tape Wednesday in an effort to show that Weinberg set up the senator by coaching him on what to say to the "sheik."

They claim Weinberg did the same to their clients. This is part of their defense that the defendants had no intention of breaking federal bribery laws even though they accepted and split $50,000 in cash.

Defense attorneys objected continuously throughout prosecutor Puccio's questioning of Weinberg, especially when the prosecutor asked the witness if he'd ever heard of the saying "you can't con an honest man."

U.S. District Court Judge George C. Pratt said he regretted being unable to keep out evidence that might be unfair to other parties. But he said he was allowing Puccio to question Weinberg about Williams' involvement to help the jury understand the taped conversation they had heard the day before.

Weinberg told Raymond A. Brown, attorney for defendant Angelo Errichetti, that Williams was nervous about the June 28 meeting with the "sheik." "He was worried about the suit he wore. What name he called him," Weinberg said.

Weinberg said the senator's meeting with the "sheik" "was all part of the act, to get him to say what he would do to get the money" (loan money). But the witness insisted that Williams wasn't set up. "He knew exactly what he was coming there for.

"The whole deal relied upon [whether] he could get government contracts," Weinberg said.

Informer Weinberg did most of the talking during the meeting, telling Williams to come on strong and tell the "sheik" that he had the influence to guarantee the government contracts.

"That's why it comes down to metal [titanium is a metallic element] is the big thing," Williams responded, somewhat obscurely. "That's the government area."

At another point, the senator said, "What's the deal with Yassir [the "sheik"] gonna be, just strictly loans?"

Weinberg replied that the loan would be at the prime rate, and added that the "best part -- why you gotta sell like mad" -- is that the "sheik" would give the investment group carte blanche if they wanted to buy anything besides the mine and plant.

On the tape, just before Williams was sent in to meet the sheik, Weinberg said, "Come on as strong as possible. It won't offend him. This is the Arab way."

In a final word, he added "So are you ready to go on stage?"

"Yea," Williams said.