Union Carbide Corp. yesterday reported a record $582 million loss for 1985, reflecting the heavy cost of the company's reorganization and recent successful fight to avoid a hostile takeover.

The petrochemical firm, which is based in Danbury, Conn., also estimated that it will spend $185 million on legal costs, including the more than 125 lawsuits stemming from the poison-gas disaster in Bhopal, India, in December 1984. This estimate, which was charged against the company's earnings during the last three months of 1985, represented the first time that Carbide has placed a price tag on the accident that killed more than 2,000 Indians.

Stanley Chesley, one of the lawyers representing Bhopal victims, said the figure is "absurdly low" and "doesn't even come close" to what would be needed for a just settlement to compensate his clients.

The earnings report -- the worst in Carbide's history -- follows a tumultuous year that included the fallout from the Bhopal disaster, a widely publicized chemical leak in Institute, W. Va., a major internal restructuring that is resulting in the layoff of 4,000 white-collar workers and a costly hostile takeover bid launched by GAF Corp.

Carbide said its 1985 loss, which amounted to $8.35 a share, reflected $1.19 billion in pretax charges stemming from write-offs and write-downs of assets and other costs associated with the restructuring program, as well as $57.6 million for a stock share-exchange program designed to stave off the takeover bid by GAF.

In addition, Carbide reported that its 1985 sales declined 5 percent from 1984 to $9 billion, because of what it called "weak pricing and divestitures" completed during the year. Only the industrial gases and consumer products divisions reported sales increases, and the latter is being sold as a result of the GAF fight.

Carbide said its net income before the special charges was $341 million, compared with $323 million in 1984. For the fourth quarter, Carbide posted a $211 million loss, compared with net income of $13 million in the fourth quarter of 1984.

A Carbide spokesman said the $185 million charge for legal costs -- which included estimates for Bhopal as well as patent, product-liability and trade-regulation cases -- was included because of accounting principles that require a company to include such estimates when a case has progressed to a point where it could have a material impact on the company. The spokesman said that it does not mean that Carbide expects an imminent settlement of the case, but he noted that further settlement negotiations have been scheduled with the plaintiffs for early next month.

News services also reported the following earnings reports yesterday:

*Transworld Corp. reported sharply higher net income for the fourth quarter and all of 1985, with much of the increase coming from the sale of its Century 21 Real Estate Corp. subsidiary.

In the fourth quarter, the food and lodging company's net income was $133.6 million ($3.49 a share), up from $29.6 million (70 cents) in the corresponding 1984 period.

Income for the quarter and the year was boosted by a $102.8 million after-tax gain on the sale of Century 21 to Metropolitan Life Insurance Co.

Fourth-quarter revenue was $654.7 million, up from $507.2 million in the last 1984 period.

In 1985, Transworld earned $217.5 million ($5.60) compared with $115 million ($3.00) the previous year.

Revenue in 1985 was $2.2 billion, up from $1.9 billion.

*Delta Air Lines reported a 39 percent decline in profits for its 1985 fiscal year, which it blamed on a long-term fare war and competition from low-cost carriers.

The airline, which is based in Atlanta, showed net income for 1985 of $156.7 million ($3.92 a share), compared with $258.6 million ($6.50) in 1984.

Fourth-quarter net income totaled $1.8 million (5 cents), 97 percent less than the $73.9 million ($1.85) earned in the last 1984 quarter.

*Union Pacific Corp., a transportation and energy company, reported that its fourth-quarter earnings increased 5 percent, to $135 million ($1.13 a share) from $128 million ($1.05) in 1984.

The company, which is based in New York, said revenue in the fourth quarter was $2.1 billion, compared with $1.9 billion.

For the year, earnings totaled $501 million (4.18), compared with $494 million ($4.01) in the previous year.

Revenue for the year totaled $7.9 billion, level with last year.

*American Express Co. said its fourth-quarter earnings increased 61 percent, to $273 million, with all of its divisions posting higher profits.

For the year, earnings increased 33 percent, to $810 million.

Last October, the company spun off 59 percent of its Fireman's Fund's insurance business in the biggest initial public offering in U.S. history and reported a gain of $52 million from the offering.

*Dow Jones & Co. Inc. said its fourth-quarter profits climbed 18.7 percent from a year earlier despite a 9.1 percent drop in advertising linage in the company's flagship newspaper, The Wall Street Journal.

Dow Jones, which also publishes the financial magazine Barron's and has interests in book publishing and information services, said fourth-quarter net income rose to $40.9 million (63 cents a share) from $34.4 million (54 cents) a year earlier. Revenue rose 8.4 percent, to $278.7 million from $257.1 million.

For the full year, net income climbed 7.3 percent, to $138.6 million ($2.15) from $129.1 million ($2.01) in 1984, the company said. Annual revenue was up 7.6 percent to $1.04 billion from $965.6 million.