Bethlehem Steel Corp. reported a sharp decline in fourth-quarter profits compared to 1978, but said yesterday that it earned a near-record $276 million for the full year of 1979.

Company Chairman Lewis Foy said the year-end performance was the second best in Bethlehem's 75-year history and was exceeded only in 1974, when a profit of $342 million was reported.

Per-share earnings for the year amounted to $6.31 on sales of $7.1 billion. In 1978, Bethlehem earned $225.1 million ($5.15 a share) on sales of $6.2 billion.

The board of directors also declared a dividend of 40 cents a common share.

For the quarter, Bethlehem had net income of $38.6 million (88 cents), a 48 percent drop from the same period in 1978 when net income was $74.5 million ($1.70). Sales for the 1979 quarter were $1.76 billion versus $1.64 billion in 1978.

A day earlier, U.S. Steel Corp. reported a year-end loss of $293 million and a fourth-quarter deficit of $561.7 million, the largest quarterly loss in American corporate history.

The red ink reflects U.S. Steel's decision in late 1979 to shut down more than a dozen unprofitable facilities, affecting about 13,000 employes.

U.S. Steel is the nation's largest steel producer, Bethlehem is ranked second. In 1977, Bethlehem posted a net loss of $448 million, largely due to its own retrenchment that cost about $750 million.

Foy said earnings showed a strong upward trend through the first three quarters of last year and declined as expected in the last quarter because of the economic slowdown and continued inflation.

Bethlehem's return on equity for 199 was 11.7 percent, an improvement over the 10.3 percent reported in 1978, but still below the average for all U.S. manufacturing, Foy said.

Foy said the company expects business to be weaker in 1980 than it was in 1979, both in terms of shipments and profits. The company shipped 13.4 million tons in 1979.

Foy said he expects industry shipments in 1980 to be between 90 million and 93 million tons, down from the 100 million tons shipped in 1979. He predicted imports will be about 16 million tons for 1980 compared with 17 million tons last year.

Westinghouse Electric Corp., which was plagued by a seven-week strike last summer, lost $73.9 million in 1979 in sharp contrast to the $243.4 million ($2.81 a share) it earned in 1978, Westinghouse said yesterday.

The company's sales increased from $6.7 billion to $7.3 billion.

Although Westinghouse said the strike adversely affected operations, it didn't disclose a dollar figure on the impact. However, the company attributed a good part of the loss to costs of settling eight uranium supply lawsuits.

In the fourth quarter, the loss was $116.8 million in contrast with net income of $75.1 million (87 cents) in the like period of 1978. Sales increased from $1.8 billion to $2 billion.

"Westinghouse has now accounted for the estimated cost of settling 14 of the 17 lawsuits brought by electric utilities in 1975 and has made a provision to cover the remaining cases and related uranium litigation," said Chairman Robert Kirby.

Westinghouse would have earned $331.1 million ($3.85) in 1979 if not for the uranium settlements and its fourth-quarter earnings would have been $106 million ($1.24), the company said.

In 1978, earnings before the uranium losses were $311.3 million ($3.59).

Kirby said the company's three operating units -- power systems, industry products and public systems -- all posted higher sales during the year.

Philip Morris Inc. announced a 20.7 percent gain in profits last year on a rise of 25.2 percent in sales.

Net income was $507.88 million ($4.08 a share) on sales of $8.303 billion compared with $408.58 million ($3.38) in 1978 on sales of $6.632 billion.

In the final quarter, Philip Morris earned $122.95 million (99 cents) on sales of $2.156 billion compared with $101.56 million (84 cents) a year earlier on sales of $1.752 billion.

Chairman George Weissman said the company's cigarette brands again outperformed the industry with sales gains of 13.5 percent and an operating income rise of 23.4 percent. The Miller Brewing subsidiary had a 21.9 percent sales gain and a 20.4 percent rise in profit. Seven-Up soft drink sales were up 58.4 percent but operating earnings from the division were down sharply because of large outlays on expansion.