What was going on when I was born?

President Reagan's decision Tuesday to ask other countries to limit their steel shipments to the United States was presented by the White House as upholding the principles of free trade. But the recent history of ''voluntary'' export restraint suggests it is potentially the most protectionist action this Administration has yet taken. Although the White House said the President was rejecting the mandatory quotas sought by American steel producers and the United Steelworkers, the practical effect of Mr. Reagan's decision will be little different. ''We are moving toward globally managed trade in steel, similar to what already exists in textiles,'' commented Robert Z. Lawrence, senior fellow at the Brookings Institution. Barely noticed among documents handed out by the White House Tuesday in connection with the Presidential decision was a 12-page list of all the ''unfair'' trade practices of just about every steel-producing nation.

The worst cheating scandal in nearly 20 years at the Air Force Academy has prompted the Air Force to suspend the cadet-run system of discipline for honor code violations pending a thorough review of the academy's strict honor system. The re-examination of the academy's honor code, in which cadets pledge neither to lie, cheat nor steal nor to tolerate those who do, stemmed from evidence of large-scale cheating on a senior-class physics test last spring. In June, 19 seniors were suspended for a year and the cadet-run Honor Boards, which investigate possible violations of the code, were suspended. Academy officials are certain, however, that more cadets cheated than the 19 who were suspended, and that the cadet-run trials acquitted a number of cadets despite what one official called ''overwhelming evidence'' that they had cheated.

From his cornfield, James Lombardi can see just the tip of the silo. ''The tower,'' as it is called here, is only 165 feet tall, but it has cast a long shadow across this community of 3,325 people by the swift Niagara River. Inside the crumbling concrete structure are packed tons of radioactive waste from the Manhattan Project - the World War II research effort that led to the development of the atomic bomb. Now, after years of denying that there was any radioactive material at the site, the Federal Government is beginning to talk publicly about its plans for more secure storage of the waste in the silo and in other areas of the 190-acre Government reservation that juts into the town of Lewiston. The radioactivity has contaminated large amounts of land on the reservation and patches off it that once were part of the reservation, according to a Federal evironmental report.

The people of Brownsville, like those in other poor neighborhoods, believe that their community lies somewhere beyond America's line of vision. It comes into view only occasionally, when cries over some perceived wrong mount into screams, when riot-sparked fires illuminate rage or when a criminal act makes news. It is a community that outsiders, and some residents, often define by negative highs: The high number of abandoned buildings and vacant lots. The high degree of devastation. The high concentration of welfare recipients. High unemployment. High crime. Children and adults getting high on the high concentration of drugs. Yet, in some ways, the Brownsville section of Brooklyn is like any other place that people call home. Its inhabitants include everyday people who lead everyday lives, putting one foot in front of the other in search of possibilities. Sometimes life is good, sometimes it is bad, sometimes it just is. William Anthony is rearing a family there.

The Florida Agriculture Commissioner approved an emergency measure today empowering state agents to decide on the spot whether to burn citrus trees and destroy crops that they suspect of carrying a virulent disease. In a second move to control the citrus canker that imperils the state's $2.5 billion orange and grapefruit industry, his department banned all shipping of uninspected citrus fruit within the state. Scientists today reported two new outbreaks of canker, bringing the number of nurseries affected to five. But while evidence of the spread of the bacterial disease is building with each passing day, no one can say how far it has ranged or how many trees will have to be burned to halt its progress. Disease Highly Contagious The highly contagious disease apparently attacks all varieties of oranges, grapefruits, tangerines, lemons and limes. Canker scars fruit with a yellowish-brownish lesion and can defoliate and kill trees. But scientists say it is harmless to people and animals.

THURSDAY, SEPTEMBER 20, 1984 International The sovereignty of Hong Kong would be transferred from Britain to China in 1997 under a draft agreement reached by London and Peking after two years of sometimes contentious negotiations. The accord may be initialed soon. (Page A1, Column 1.) A budget-cutting plan by Israel must be presented before Washington will consider a big increase in economic aid for the new Israeli Government, according to State Department officials. (A12:4-6.)

Construction of new houses skidded 12.8 percent in August, to an annual rate of 1,537,000 units, the lowest since December 1982, the Commerce Department reported today. The decline, which was steeper than most analysts expected, was mainly attributed to rising interest rates that, for conventional mortgages, briefly exceeded 15 percent this summer. August was the second consecutive month of falling housing starts, representing further evidence of an overall slowing of the economic expansion dating from late 1982. The Commerce Department also reported today that personal income and spending rose by smaller amounts last month than in July. The department is to publish Thursday its initial, or ''flash,'' estimate of third- quarter gross national product, the broadest measure of the nation's output of goods and services. The estimate is certain to be well below the 7.6 percent annual growth rate of the second quarter.

The Sports of The Times column yesterday quoted an incorrect chronology of events in the Korean War. MacArthur's landing at Inchon occurred in September 1950 and was followed, in order, by the Chinese intervention and the retreat of the United Nations forces to Pusan.

The method by which local television stations are charged for the right to use copyrighted music has been declared legal by a Federal appeals court. In a decision reached late Tuesday, the United States Court of Appeals for the Second Circuit reversed a 1982 decision that found that the arrangement violated antitrust laws. The ruling came in a suit filed on behalf of 750 local television stations that challenged the blanket licensing system used by the American Society of Composers, Authors and Publishers and by Broadcast Music Inc. Stations Pay Blanket Fee Under the arrangement, Ascap and B.M.I. permit a local station to use whatever songs it wishes in exchange for an annual fee based on a fixed percentage of the station's revenues. The stations have complained that the blanket fee constitutes an anticompetitive tax on revenues and does not reflect the quantity or quality of music that they play.

The Dow Jones industrial average plunged yesterday as a late selloff erased its earlier gains. However, the general market finished with only minor losses in heavy trading. The Dow average, which is composed of 30 blue-chip issues, fell 13.25 points, to 1,213.01, after being ahead more than 2 points at 3 P.M. In the overall market, declining issues narrowly outnumbered advancing ones by 804 to 778, with the blue-chip and technology issues the main casualties. Turnover on the New York Stock Exchange, fueled by accelerated selling from insurance, bank and mutual funds, climbed to 120 million shares, from 107.8 million shares on Tuesday.

High school graduates scored an average of four points higher on the major test that colleges use in making admissions decisions than graduates of a year earlier, the College Board reported yesterday. It was the largest gain since the Scholastic Aptitude Test scores began their much-discussed decline in 1963. The averages rose by one point on the verbal section, to 426, and by three points on the mathematics section, to 471. The highest score is 800 and the lowest is 200.

A report in the Executive Changes column of Business Day yesterday misidentified the new positions of two officials at CPC International Inc. David Newstadt and Robert J. Gillespie were named executive vice presidents of CPC's Best Foods North America division.