United States Steel Corp., the nation's largest steel maker, yesterday reported what its chairman called "very disappointing" earnings and sales figures for the second quarter of 1977.

Net income was $76.3 million (91 cents a share) compared with $119.6 million ($1.47) a year ago. Sales rose slightly, however, to $2.58 billion from $2.40 billion.

U.S. Steel chairman Edgar B. Speer attributed the decline in earnings to the high level of steel imports and a "continuing lag in recovery of demand from the capital-goods sector of the market."

Speer lashed out at subsidies given by foreign governments to their nations' steel companies, which he said allow the firms to sell steel in America for less than it costs them.

U.S. Steel has filed suit in federal court seeking to force the government to impose duties on imported steel to make the situation more equitable.

Shell Oil Co., Continental Oil Co., Phillips Petroluem Co., and Marathon Oil Co. yesterday announced improved second-quarter results, reflecting the generally upbeat financial reports released recently by major oil producers.

Shell, the seventh-target U.S. oil firm, said second-quarter net income was $172 million ($1.21 a share) compared with $165 million (1.18) in the same period of 1976. Second-quarter revenue was $2.5 billion, up 12 per cent from last year's $2.3 billion.

Shell's second-quarter share net reflects a 2-for-1 stock split on May 6.

No. 9, Continental, listed quarterly net income as $117.4 million ($1.09 a share) compared with $113 million ($1.08). Sales were $2.3 billion up from $2.1 billion a year ago.

Phillips No. 11 in oil, had a 2-for-1 stock split on May 7, 1976.Second-quarter net income was $125 million (82 cents a share), up from $39.6 million (59 cents) in 1976. Revenues were $1.58 billion against $1.43 billion in 1976.

Marathon, the 17th largest oil producer, listed second-quarter net income as $49.6 million ($1.65 a share) this year compared with $37.1 million ($1.24) in the second quarter of 1976. Revenues increased from $888.9 million to $1.100 billion.

Rockwell Internationl Corp., the prime contractor for the canceled B1 bomber program, yesterday reported higher sales and earnings for its third fiscal quarter.

Earnings of $37 million ($1.07 a share) were 18 per cent above 1976's restated third-quarter earnings of $31.3 million (92 cents). Sales were $1.47 billion, a 12 per cent increase over sales of $1.31 billion a year ago.

Eastern Airlines had a loss of $2.6 million in June and lower earnings for the second quarter and first six months despite increased revenues.

The June loss compared with a profit of $3.96 million (20 cents a share) a year earlier.

In the second quarter, the airline had a profit of $3.2 million (16 cents) on operating revenues of $498.8 million compared with $19.3 million ($1) a year earlier on revenues of $457.3 million.

Profits for the first half dropped to $21.8 million ($1.10) on revenues of $1.02 billion from $37.1 million ($1.93) a year ago on revenues of $929.6 million.

Borden, Inc., a dairy food and chemical combine, had a 15.3 per cent gain in per share profits in the second quarter to $1.22 from $1.06 a year earlier.

Net income was $37.93 million on revenue of $915.05 million compared with $32.91 million a year earlier on revenues of $899.26 million.