What was going on when I was born?

The West Coast steel business has long been ruled by Japanese and Korean producers, whose low labor costs and technical skills long ago brought the once-reigning Kaiser Steel Corporation to its knees. Now, though, a British-born entrepreneur who is about to take over the Kaiser Works 45 miles east of here is confidently predicting that the combination of low costs and proximity to customers will enable him to overtake the leaders. ''We're looking for something on the order of 25 percent of the market within the first year, with most of it replacing imports,'' said Michael Wilkinson, president of newly formed California Steel Industries. Many steel analysts think that Mr. Wilkinson, 46 years old, who is a successful distributor and fabricator but untested in production, has a good chance to succeed. There are many reasons, they say, not the least of which is a tough, new stance at the International Trade Commission against subsidized imports.

Senior military officers, countering the view of some civilian leaders, have expressed reservations about the need for a low-altitude antisatellite weapon, according to Administration sources. Important segments of the Navy, in particular, are said to believe that ships at sea can evade detection by Soviet satellites, making it unnecessary to shoot them down. Given Navy attitudes, the Air Force, which is responsible for financing the $4 billion antisatellite program, has proposed that the number of weapons to be procured be cut by half, to 21. But civilian leaders in the Pentagon and in the Arms Control and Disarmament Agency have rejected these views and have sustained the program. They have opposed a Soviet proposal for a moratorium on testing antisatellite weapons that would accompany the start of talks suggested by the Russians for September in Vienna.

Treasury note and bond prices surged yesterday, fueled by strong demand from investors and traders who are growing more confident that interest rates might decline as evidence mounts that economic growth is moderating and inflation will remain in check. Including yesterday's gains of as much as 1 5/8 points, prices of long- term Treasury bonds have increased nearly 3 points since late Tuesday, or $30 per $1,000 bond, and about 7 1/2 points in the last four weeks. During the four-week period, the yield on 30- year Treasury bonds has fallen by slightly more than a percentage point, to 12.56 percent. Currently, bond yields are closer to the year's low of 11.6 percent in mid-January than to the year's high of 14 percent set in late May.

Wall Street turned in a record trading day yesterday, as the view took hold that economic growth had moderated to a sustainable pace. On the New York Stock Exchange, 172.8 million shares changed hands, exceeding the previous record of 159.99 million set on Jan. 5. The widely followed Dow Jones industrial average, which climbed 19.33 points on Wednesday, soared a further 31.47 points, to close at 1,166.08. It was the largest gain in 20 months. (Page D1.)

The House of Representatives voted today to take away $5 billion of spending authority from the embattled Synthetic Fuels Corporation, and it prohibited the corporation from using any of its remaining money to support two of the largest and most controversial projects it has considered. The vote, 236 to 177, was hailed by opponents of the corporation as ''an important first step,'' although they lost their effort to reduce its financing by $10 billion, from the $13.2 billion first approved by Congress in 1980. The voting came on amendments to the appropriations bill for the Interior Department. Before approving the entire bill, the House voted, 212 to 181, to cut the $8.5 billion appropriations bill for the fiscal year 1985 by 3 percent, or $247 million, across the board. This cut was proposed by Representative Joseph M. McDade, Republican of Pennsylvania, who also co-sponsored the smaller $5 billion cut in the Synthetic Fuels Corporation amount. The amended bill was then approved, 336 to 57.

''We are cautiously optimistic. But we are not sitting back and saying, 'Hey, this is great.'

Stock prices exploded yesterday in the heaviest trading on record, fueled by heavy buying from pension funds and other large institutions. At the close, the Dow Jones industrial average was up 31.47 points, to 1,166.08, after having soared 19.33 points Wednesday. Yesterday's advance in the average was its biggest since it climbed 36.43 points on Nov. 30, 1982. Volume on the New York Stock Exchange climbed to 172.8 million shares, from 127.5 million shares the day before. The previous record was 159.99 million share on Jan. 5 of this year.

The I.B.M. Settlement I.B.M. and the Common Market settled antitrust complaints in the first case of such scope and complexity. Under the agreement, I.B.M. will disclose to its rivals some advance information about its mainframe computer models that hold about 70 percent of the European market. The agreement, which is intended to give compeptitors a chance to catch up with I.B.M., can be repudiated after 1990, however. (Page A1.)

An obituary on Wednesday of Floyd E. McKee, a former senior vice president of the Bankers Trust Company, omitted the name of one survivor. She is Elizabeth Werlinich, a daughter.

He has been no stranger to illness. Perhaps no one appreciates better than he the frustrations of diagnoses, the limitations of cures. That he has become a physician, Dr. Theodore Kessler says, is linked to the fact that, at the age of 29, he is seriously ill and has no hope of recovering. Yet, he has focused his attention on other things.

Major crimes reported in New York City in the first six months of this year declined 3.1 percent from the number in the first half of 1983, according to statistics made public yesterday by the Police Department. But one of the major crimes, assault, was significantly higher. There were 22,446 reported assaults from January through June of this year, an 8.7 percent increase over the the number in the same period last year. ''We don't know why this is so,'' said Inspector James J. Trainor, the head of the Police Department's office of management analysis and planning. ''We are taking a close look at the situation.''

The International Business Machines Corporation, the world's largest computer manufacturer, today settled a decade-old antitrust case brought against it by the European Economic Community. Under the settlement, I.B.M. has agreed to alter its European marketing strategy for its most powerful range of computers and give rival European manufacturers more information about them. The case, handled by the community's Commission, its administrative arm, was the first in which the Common Market questioned the business practices of a company of I.B.M.'s size and sophistication. The pact also marks the first time the Common Market has negotiated so complicated a technical agreement on the way a company will conduct its business.