In West Germany, 230,000 members of the world's largest union are locked in a bitter labor struggle that poses a serious challenge to the traditional base of support of Chancellor Helmut Schmidt's Social Democratic Government.

Concern is mounting in Bonn that a long strike in the key metal industry could cost West Germany business billions of dollars, exacerbate the country's rate of inflation and have a negative effect on West Germany exports.

Since World War II, West Germany many's highly disciplined unions traditionally have earned a reputation for responsibility, and strikes of more than a few days have been rare. In fact, the German record for labor peace had been unparalleled in the West.

In the past three years, West German industry lost an average of 25 working days per 1,000 workers due to strikes. In Japan and France, the rate was 10 times higher and 20 times higher in Uniter States. Italy lost an average of 70 times as many working days per 1,000 workers.

This type of labor stability has helped West German industry gain a reputation for reliability. And largely without restoring to strike, West German workers have been able to increase their wages and fringe benefits to the point that they are among the highest paid in the industrialized West.

West German employers insist that their labor costs are already the highest in the world, and in an effort to keep their products competitive, have pledged to grant only minimal increases this year. Amid such brewing labor unrest, there are signs that West Germany's traditional "social partnership" is eroding.

At the heart of the current labor struggle is the 2.6-million strong IG Metall union, which represents steel, auto, electrical workers and machinist. The metal workers' contracts usually set the trend for all of West German industry.

The metal strike has had its most devastating effect in the Stuttgart from the Daimler-Benz and Porsche auto works and the Bosch electrical plant,walked off their jobs March 15.

Nearly 80 company managers in the northern part of Baden-Wuerttemberg, where IG Metall is concentrating the strike effort, responded with by immediately locking out another 150,000 workers.

Another development is evident in West Germany's current labor difficulties, according to informed observeds: for the first time in postwar history job security appears to have overtaken wages demands as the unions' main concern, as companies are putting more money into labor-saving devices.

"We are especially concerned about technological changes that are becoming more and more threatening for a lot of workers," said Eugen Loderer, the head of IG Metall, in an interview last week with the newsmagazine Der Spiegel.

A recent one-week German newspaper strike had as its central issue job security in the face of expected advances in the use of computerized editing any typesetting systems.

Wages, however, are in the foreground of hte metal strike, and IG Metall's militant Baden-Wuerttemberg district leader Frank Steinkuehler is pressing for wage increases of 8 percent; employers have offered 3.5 percent.

The strike already has begun to have an impact outside the Stuttgart area, especially in the key auto industry. Volkswagen and Ford of Cologne have both announced shorter hours for some workers and other plants have announced layoffs.

Labor Minister Herbert Ehrenberg, in Washington recently to met with U.S. Cabinet officials, minimixed the impact of the metal workers' strike.

"At little short-time work at Volkswagen won't cause the German auto industry to go bankrupt, with its good resources," Bhreberg said. "I don't see . . . and great catastrpe because of a strike in the metal industry."

Despite Ehrenberg's public optimism, however, observers feel there is growing concern in the Cabinet over the potential economic disruption.

Last year, West Germany ran up a trade surplus of $18 billion, and much of this came through auto and machine-tool exports. Even before the strike, however, West German exports were feeling the pressure of increased foreign competition, and were also being affected by the rise in the value of the West German mark.

Experts fear that a long strike and rising labor costs in general will discourage investment, harm exports and slow down economic growth. The Bonn government has projected a modest 3.5 percent growth rate for the current year.

There have been recent signs that the economy is expanding somewhat more rapidly, and before the metal strike, one respected research organization predicted a first-quarter growth rate closer to 6 percent.